demandimport: delay loading for "from a import b" with absolute_import

Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.

For example:

  - it is assumed that extension X has "from P import M" for module M
    under package P with absolute_import feature

  - if importing module M is already delayed before loading extension
    X, loading module M in extension X is delayed until actually
    referring

    util, cmdutil, scmutil or so of Mercurial itself should be
    imported by "from . import M" style before loading extension X

  - otherwise, module M is loaded immediately at loading extension X,
    even if extension X itself isn't used at that "hg" command invocation

    Some minor modules (e.g. filemerge or so) of Mercurial itself
    aren't imported by "from . import M" style before loading
    extension X. And of course, external libraries aren't, too.

This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.

To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:

  1. import root module of "name" by system built-in __import__
     (referred as _origimport)

  2. recurse down the module chain for hierarchical "name"

     This logic can be shared with non absolute_import
     case. Therefore, this patch also centralizes it into chainmodules().

  3. and fall through to process elements in "fromlist" for the leaf
     module of "name"

     Processing elements in "fromlist" is executed in the code path
     after "if _pypy: .... else: ..." clause. Therefore, this patch
     replaces "if _pypy:" with "elif _pypy:" to share it.

At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.

IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.

This is reason why this patch removes "errors for unknown reasons"
comment.

mercurial/demandimport.py

@@ -1,288 +1,291 b''
 # demandimport.py - global demand-loading of modules for Mercurial
 #
 # Copyright 2006, 2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 '''
 demandimport - automatic demandloading of modules
 
 To enable this module, do:
 
   import demandimport; demandimport.enable()
 
 Imports of the following forms will be demand-loaded:
 
   import a, b.c
   import a.b as c
   from a import b,c # a will be loaded immediately
 
 These imports will not be delayed:
 
   from a import *
   b = __import__(a)
 '''
 
 from __future__ import absolute_import
 
 import contextlib
 import os
 import sys
 
 # __builtin__ in Python 2, builtins in Python 3.
 try:
     import __builtin__ as builtins
 except ImportError:
     import builtins
 
 contextmanager = contextlib.contextmanager
 
 _origimport = __import__
 
 nothing = object()
 
 # Python 3 doesn't have relative imports nor level -1.
 level = -1
 if sys.version_info[0] >= 3:
     level = 0
 _import = _origimport
 
 def _hgextimport(importfunc, name, globals, *args, **kwargs):
     try:
         return importfunc(name, globals, *args, **kwargs)
     except ImportError:
         if not globals:
             raise
         # extensions are loaded with "hgext_" prefix
         hgextname = 'hgext_%s' % name
         nameroot = hgextname.split('.', 1)[0]
         contextroot = globals.get('__name__', '').split('.', 1)[0]
         if nameroot != contextroot:
             raise
         # retry to import with "hgext_" prefix
         return importfunc(hgextname, globals, *args, **kwargs)
 
 class _demandmod(object):
     """module demand-loader and proxy"""
     def __init__(self, name, globals, locals, level=level):
         if '.' in name:
             head, rest = name.split('.', 1)
             after = [rest]
         else:
             head = name
             after = []
         object.__setattr__(self, "_data",
                            (head, globals, locals, after, level, set()))
         object.__setattr__(self, "_module", None)
     def _extend(self, name):
         """add to the list of submodules to load"""
         self._data[3].append(name)
 
     def _addref(self, name):
         """Record that the named module ``name`` imports this module.
 
         References to this proxy class having the name of this module will be
         replaced at module load time. We assume the symbol inside the importing
         module is identical to the "head" name of this module. We don't
         actually know if "as X" syntax is being used to change the symbol name
         because this information isn't exposed to __import__.
         """
         self._data[5].add(name)
 
     def _load(self):
         if not self._module:
             head, globals, locals, after, level, modrefs = self._data
             mod = _hgextimport(_import, head, globals, locals, None, level)
             # load submodules
             def subload(mod, p):
                 h, t = p, None
                 if '.' in p:
                     h, t = p.split('.', 1)
                 if getattr(mod, h, nothing) is nothing:
                     setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__))
                 elif t:
                     subload(getattr(mod, h), t)
 
             for x in after:
                 subload(mod, x)
 
             # Replace references to this proxy instance with the actual module.
             if locals and locals.get(head) == self:
                 locals[head] = mod
 
             for modname in modrefs:
                 modref = sys.modules.get(modname, None)
                 if modref and getattr(modref, head, None) == self:
                     setattr(modref, head, mod)
 
             object.__setattr__(self, "_module", mod)
 
     def __repr__(self):
         if self._module:
             return "<proxied module '%s'>" % self._data[0]
         return "<unloaded module '%s'>" % self._data[0]
     def __call__(self, *args, **kwargs):
         raise TypeError("%s object is not callable" % repr(self))
     def __getattribute__(self, attr):
         if attr in ('_data', '_extend', '_load', '_module', '_addref'):
             return object.__getattribute__(self, attr)
         self._load()
         return getattr(self._module, attr)
     def __setattr__(self, attr, val):
         self._load()
         setattr(self._module, attr, val)
 
 _pypy = '__pypy__' in sys.builtin_module_names
 
 def _demandimport(name, globals=None, locals=None, fromlist=None, level=level):
     if not locals or name in ignore or fromlist == ('*',):
         # these cases we can't really delay
         return _hgextimport(_import, name, globals, locals, fromlist, level)
     elif not fromlist:
         # import a [as b]
         if '.' in name: # a.b
             base, rest = name.split('.', 1)
             # email.__init__ loading email.mime
             if globals and globals.get('__name__', None) == base:
                 return _import(name, globals, locals, fromlist, level)
             # if a is already demand-loaded, add b to its submodule list
             if base in locals:
                 if isinstance(locals[base], _demandmod):
                     locals[base]._extend(rest)
                 return locals[base]
         return _demandmod(name, globals, locals, level)
     else:
         # There is a fromlist.
         # from a import b,c,d
         # from . import b,c,d
         # from .a import b,c,d
 
         # level == -1: relative and absolute attempted (Python 2 only).
         # level >= 0: absolute only (Python 2 w/ absolute_import and Python 3).
         # The modern Mercurial convention is to use absolute_import everywhere,
         # so modern Mercurial code will have level >= 0.
 
         # The name of the module the import statement is located in.
         globalname = globals.get('__name__')
 
         def processfromitem(mod, attr):
             """Process an imported symbol in the import statement.
 
             If the symbol doesn't exist in the parent module, it must be a
             module. We set missing modules up as _demandmod instances.
             """
             symbol = getattr(mod, attr, nothing)
             if symbol is nothing:
                 mn = '%s.%s' % (mod.__name__, attr)
                 if mn in ignore:
                     importfunc = _origimport
                 else:
                     importfunc = _demandmod
                 symbol = importfunc(attr, mod.__dict__, locals, level=1)
                 setattr(mod, attr, symbol)
 
             # Record the importing module references this symbol so we can
             # replace the symbol with the actual module instance at load
             # time.
             if globalname and isinstance(symbol, _demandmod):
                 symbol._addref(globalname)
 
+        def chainmodules(rootmod, modname):
+            # recurse down the module chain, and return the leaf module
+            mod = rootmod
+            for comp in modname.split('.')[1:]:
+                if getattr(mod, comp, nothing) is nothing:
+                    setattr(mod, comp,
+                            _demandmod(comp, mod.__dict__, mod.__dict__))
+                mod = getattr(mod, comp)
+            return mod
+
         if level >= 0:
-            # The "from a import b,c,d" or "from .a import b,c,d"
-            # syntax gives errors with some modules for unknown
-            # reasons. Work around the problem.
             if name:
-                return _hgextimport(_origimport, name, globals, locals,
-                                    fromlist, level)
-
-            if _pypy:
+                # "from a import b" or "from .a import b" style
+                rootmod = _hgextimport(_origimport, name, globals, locals,
+                                       level=level)
+                mod = chainmodules(rootmod, name)
+            elif _pypy:
                 # PyPy's __import__ throws an exception if invoked
                 # with an empty name and no fromlist.  Recreate the
                 # desired behaviour by hand.
                 mn = globalname
                 mod = sys.modules[mn]
                 if getattr(mod, '__path__', nothing) is nothing:
                     mn = mn.rsplit('.', 1)[0]
                     mod = sys.modules[mn]
                 if level > 1:
                     mn = mn.rsplit('.', level - 1)[0]
                     mod = sys.modules[mn]
             else:
                 mod = _hgextimport(_origimport, name, globals, locals,
                                    level=level)
 
             for x in fromlist:
                 processfromitem(mod, x)
 
             return mod
 
         # But, we still need to support lazy loading of standard library and 3rd
         # party modules. So handle level == -1.
         mod = _hgextimport(_origimport, name, globals, locals)
-        # recurse down the module chain
-        for comp in name.split('.')[1:]:
-            if getattr(mod, comp, nothing) is nothing:
-                setattr(mod, comp,
-                        _demandmod(comp, mod.__dict__, mod.__dict__))
-            mod = getattr(mod, comp)
+        mod = chainmodules(mod, name)
 
         for x in fromlist:
             processfromitem(mod, x)
 
         return mod
 
 ignore = [
     '__future__',
     '_hashlib',
     # ImportError during pkg_resources/__init__.py:fixup_namespace_package
     '_imp',
     '_xmlplus',
     'fcntl',
     'win32com.gen_py',
     '_winreg', # 2.7 mimetypes needs immediate ImportError
     'pythoncom',
     # imported by tarfile, not available under Windows
     'pwd',
     'grp',
     # imported by profile, itself imported by hotshot.stats,
     # not available under Windows
     'resource',
     # this trips up many extension authors
     'gtk',
     # setuptools' pkg_resources.py expects "from __main__ import x" to
     # raise ImportError if x not defined
     '__main__',
     '_ssl', # conditional imports in the stdlib, issue1964
     '_sre', # issue4920
     'rfc822',
     'mimetools',
     'sqlalchemy.events', # has import-time side effects (issue5085)
     # setuptools 8 expects this module to explode early when not on windows
     'distutils.msvc9compiler'
     ]
 
 def isenabled():
     return builtins.__import__ == _demandimport
 
 def enable():
     "enable global demand-loading of modules"
     if os.environ.get('HGDEMANDIMPORT') != 'disable':
         builtins.__import__ = _demandimport
 
 def disable():
     "disable global demand-loading of modules"
     builtins.__import__ = _origimport
 
 @contextmanager
 def deactivated():
     "context manager for disabling demandimport in 'with' blocks"
     demandenabled = isenabled()
     if demandenabled:
         disable()
 
     try:
         yield
     finally:
         if demandenabled:
             enable()

tests/test-extension.t

@@ -1,1270 +1,1455 b''
 Test basic extension support
 
   $ cat > foobar.py <<EOF
   > import os
   > from mercurial import cmdutil, commands
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > def uisetup(ui):
   >     ui.write("uisetup called\\n")
   >     ui.flush()
   > def reposetup(ui, repo):
   >     ui.write("reposetup called for %s\\n" % os.path.basename(repo.root))
   >     ui.write("ui %s= repo.ui\\n" % (ui == repo.ui and "=" or "!"))
   >     ui.flush()
   > @command('foo', [], 'hg foo')
   > def foo(ui, *args, **kwargs):
   >     ui.write("Foo\\n")
   > @command('bar', [], 'hg bar', norepo=True)
   > def bar(ui, *args, **kwargs):
   >     ui.write("Bar\\n")
   > EOF
   $ abspath=`pwd`/foobar.py
 
   $ mkdir barfoo
   $ cp foobar.py barfoo/__init__.py
   $ barfoopath=`pwd`/barfoo
 
   $ hg init a
   $ cd a
   $ echo foo > file
   $ hg add file
   $ hg commit -m 'add file'
 
   $ echo '[extensions]' >> $HGRCPATH
   $ echo "foobar = $abspath" >> $HGRCPATH
   $ hg foo
   uisetup called
   reposetup called for a
   ui == repo.ui
   Foo
 
   $ cd ..
   $ hg clone a b
   uisetup called
   reposetup called for a
   ui == repo.ui
   reposetup called for b
   ui == repo.ui
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ hg bar
   uisetup called
   Bar
   $ echo 'foobar = !' >> $HGRCPATH
 
 module/__init__.py-style
 
   $ echo "barfoo = $barfoopath" >> $HGRCPATH
   $ cd a
   $ hg foo
   uisetup called
   reposetup called for a
   ui == repo.ui
   Foo
   $ echo 'barfoo = !' >> $HGRCPATH
 
 Check that extensions are loaded in phases:
 
   $ cat > foo.py <<EOF
   > import os
   > name = os.path.basename(__file__).rsplit('.', 1)[0]
   > print "1) %s imported" % name
   > def uisetup(ui):
   >     print "2) %s uisetup" % name
   > def extsetup():
   >     print "3) %s extsetup" % name
   > def reposetup(ui, repo):
   >    print "4) %s reposetup" % name
   > EOF
 
   $ cp foo.py bar.py
   $ echo 'foo = foo.py' >> $HGRCPATH
   $ echo 'bar = bar.py' >> $HGRCPATH
 
 Command with no output, we just want to see the extensions loaded:
 
   $ hg paths
   1) foo imported
   1) bar imported
   2) foo uisetup
   2) bar uisetup
   3) foo extsetup
   3) bar extsetup
   4) foo reposetup
   4) bar reposetup
 
 Check hgweb's load order:
 
   $ cat > hgweb.cgi <<EOF
   > #!/usr/bin/env python
   > from mercurial import demandimport; demandimport.enable()
   > from mercurial.hgweb import hgweb
   > from mercurial.hgweb import wsgicgi
   > application = hgweb('.', 'test repo')
   > wsgicgi.launch(application)
   > EOF
 
   $ REQUEST_METHOD='GET' PATH_INFO='/' SCRIPT_NAME='' QUERY_STRING='' \
   >    SERVER_PORT='80' SERVER_NAME='localhost' python hgweb.cgi \
   >    | grep '^[0-9]) ' # ignores HTML output
   1) foo imported
   1) bar imported
   2) foo uisetup
   2) bar uisetup
   3) foo extsetup
   3) bar extsetup
   4) foo reposetup
   4) bar reposetup
 
   $ echo 'foo = !' >> $HGRCPATH
   $ echo 'bar = !' >> $HGRCPATH
 
 Check "from __future__ import absolute_import" support for external libraries
 
 #if windows
   $ PATHSEP=";"
 #else
   $ PATHSEP=":"
 #endif
   $ export PATHSEP
 
   $ mkdir $TESTTMP/libroot
   $ echo "s = 'libroot/ambig.py'" > $TESTTMP/libroot/ambig.py
   $ mkdir $TESTTMP/libroot/mod
   $ touch $TESTTMP/libroot/mod/__init__.py
   $ echo "s = 'libroot/mod/ambig.py'" > $TESTTMP/libroot/mod/ambig.py
 
 #if absimport
   $ cat > $TESTTMP/libroot/mod/ambigabs.py <<EOF
   > from __future__ import absolute_import
   > import ambig # should load "libroot/ambig.py"
   > s = ambig.s
   > EOF
   $ cat > loadabs.py <<EOF
   > import mod.ambigabs as ambigabs
   > def extsetup():
   >     print 'ambigabs.s=%s' % ambigabs.s
   > EOF
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}/libroot; hg --config extensions.loadabs=loadabs.py root)
   ambigabs.s=libroot/ambig.py
   $TESTTMP/a (glob)
 #endif
 
 #if no-py3k
   $ cat > $TESTTMP/libroot/mod/ambigrel.py <<EOF
   > import ambig # should load "libroot/mod/ambig.py"
   > s = ambig.s
   > EOF
   $ cat > loadrel.py <<EOF
   > import mod.ambigrel as ambigrel
   > def extsetup():
   >     print 'ambigrel.s=%s' % ambigrel.s
   > EOF
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}/libroot; hg --config extensions.loadrel=loadrel.py root)
   ambigrel.s=libroot/mod/ambig.py
   $TESTTMP/a (glob)
 #endif
 
 Check absolute/relative import of extension specific modules
 
   $ mkdir $TESTTMP/extroot
   $ cat > $TESTTMP/extroot/bar.py <<EOF
   > s = 'this is extroot.bar'
   > EOF
   $ mkdir $TESTTMP/extroot/sub1
   $ cat > $TESTTMP/extroot/sub1/__init__.py <<EOF
   > s = 'this is extroot.sub1.__init__'
   > EOF
   $ cat > $TESTTMP/extroot/sub1/baz.py <<EOF
   > s = 'this is extroot.sub1.baz'
   > EOF
   $ cat > $TESTTMP/extroot/__init__.py <<EOF
   > s = 'this is extroot.__init__'
   > import foo
   > def extsetup(ui):
   >     ui.write('(extroot) ', foo.func(), '\n')
   >     ui.flush()
   > EOF
 
   $ cat > $TESTTMP/extroot/foo.py <<EOF
   > # test absolute import
   > buf = []
   > def func():
   >     # "not locals" case
   >     import extroot.bar
   >     buf.append('import extroot.bar in func(): %s' % extroot.bar.s)
   >     return '\n(extroot) '.join(buf)
   > # "fromlist == ('*',)" case
   > from extroot.bar import *
   > buf.append('from extroot.bar import *: %s' % s)
   > # "not fromlist" and "if '.' in name" case
   > import extroot.sub1.baz
   > buf.append('import extroot.sub1.baz: %s' % extroot.sub1.baz.s)
   > # "not fromlist" and NOT "if '.' in name" case
   > import extroot
   > buf.append('import extroot: %s' % extroot.s)
   > # NOT "not fromlist" and NOT "level != -1" case
   > from extroot.bar import s
   > buf.append('from extroot.bar import s: %s' % s)
   > EOF
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.extroot=$TESTTMP/extroot root)
   (extroot) from extroot.bar import *: this is extroot.bar
   (extroot) import extroot.sub1.baz: this is extroot.sub1.baz
   (extroot) import extroot: this is extroot.__init__
   (extroot) from extroot.bar import s: this is extroot.bar
   (extroot) import extroot.bar in func(): this is extroot.bar
   $TESTTMP/a (glob)
 
 #if no-py3k
   $ rm "$TESTTMP"/extroot/foo.*
   $ cat > $TESTTMP/extroot/foo.py <<EOF
   > # test relative import
   > buf = []
   > def func():
   >     # "not locals" case
   >     import bar
   >     buf.append('import bar in func(): %s' % bar.s)
   >     return '\n(extroot) '.join(buf)
   > # "fromlist == ('*',)" case
   > from bar import *
   > buf.append('from bar import *: %s' % s)
   > # "not fromlist" and "if '.' in name" case
   > import sub1.baz
   > buf.append('import sub1.baz: %s' % sub1.baz.s)
   > # "not fromlist" and NOT "if '.' in name" case
   > import sub1
   > buf.append('import sub1: %s' % sub1.s)
   > # NOT "not fromlist" and NOT "level != -1" case
   > from bar import s
   > buf.append('from bar import s: %s' % s)
   > EOF
   $ hg --config extensions.extroot=$TESTTMP/extroot root
   (extroot) from bar import *: this is extroot.bar
   (extroot) import sub1.baz: this is extroot.sub1.baz
   (extroot) import sub1: this is extroot.sub1.__init__
   (extroot) from bar import s: this is extroot.bar
   (extroot) import bar in func(): this is extroot.bar
   $TESTTMP/a (glob)
 #endif
 
+#if absimport
+
+Examine whether module loading is delayed until actual refering, even
+though module is imported with "absolute_import" feature.
+
+Files below in each packages are used for descirbed purpose:
+
+- "called": examine whether "from MODULE import ATTR" works correctly
+- "unused": examine whether loading is delayed correctly
+- "used":   examine whether "from PACKAGE import MODULE" works correctly
+
+Package hierarchy is needed to examine whether demand importing works
+as expected for "from SUB.PACK.AGE import MODULE".
+
+Setup "external library" to be imported with "absolute_import"
+feature.
+
+  $ mkdir -p $TESTTMP/extlibroot/lsub1/lsub2
+  $ touch $TESTTMP/extlibroot/__init__.py
+  $ touch $TESTTMP/extlibroot/lsub1/__init__.py
+  $ touch $TESTTMP/extlibroot/lsub1/lsub2/__init__.py
+
+  $ cat > $TESTTMP/extlibroot/lsub1/lsub2/called.py <<EOF
+  > def func():
+  >     return "this is extlibroot.lsub1.lsub2.called.func()"
+  > EOF
+  $ cat > $TESTTMP/extlibroot/lsub1/lsub2/unused.py <<EOF
+  > raise Exception("extlibroot.lsub1.lsub2.unused is loaded unintentionally")
+  > EOF
+  $ cat > $TESTTMP/extlibroot/lsub1/lsub2/used.py <<EOF
+  > detail = "this is extlibroot.lsub1.lsub2.used"
+  > EOF
+
+Setup sub-package of "external library", which causes instantiation of
+demandmod in "recurse down the module chain" code path. Relative
+importing with "absolute_import" feature isn't tested, because "level
+>=1 " doesn't cause instantiation of demandmod.
+
+  $ mkdir -p $TESTTMP/extlibroot/recursedown/abs
+  $ cat > $TESTTMP/extlibroot/recursedown/abs/used.py <<EOF
+  > detail = "this is extlibroot.recursedown.abs.used"
+  > EOF
+  $ cat > $TESTTMP/extlibroot/recursedown/abs/__init__.py <<EOF
+  > from __future__ import absolute_import
+  > from extlibroot.recursedown.abs.used import detail
+  > EOF
+
+  $ mkdir -p $TESTTMP/extlibroot/recursedown/legacy
+  $ cat > $TESTTMP/extlibroot/recursedown/legacy/used.py <<EOF
+  > detail = "this is extlibroot.recursedown.legacy.used"
+  > EOF
+  $ cat > $TESTTMP/extlibroot/recursedown/legacy/__init__.py <<EOF
+  > # legacy style (level == -1) import
+  > from extlibroot.recursedown.legacy.used import detail
+  > EOF
+
+  $ cat > $TESTTMP/extlibroot/recursedown/__init__.py <<EOF
+  > from __future__ import absolute_import
+  > from extlibroot.recursedown.abs import detail as absdetail
+  > from .legacy import detail as legacydetail
+  > EOF
+
+Setup extension local modules to be imported with "absolute_import"
+feature.
+
+  $ mkdir -p $TESTTMP/absextroot/xsub1/xsub2
+  $ touch $TESTTMP/absextroot/xsub1/__init__.py
+  $ touch $TESTTMP/absextroot/xsub1/xsub2/__init__.py
+
+  $ cat > $TESTTMP/absextroot/xsub1/xsub2/called.py <<EOF
+  > def func():
+  >     return "this is absextroot.xsub1.xsub2.called.func()"
+  > EOF
+  $ cat > $TESTTMP/absextroot/xsub1/xsub2/unused.py <<EOF
+  > raise Exception("absextroot.xsub1.xsub2.unused is loaded unintentionally")
+  > EOF
+  $ cat > $TESTTMP/absextroot/xsub1/xsub2/used.py <<EOF
+  > detail = "this is absextroot.xsub1.xsub2.used"
+  > EOF
+
+Setup extension local modules to examine whether demand importing
+works as expected in "level > 1" case.
+
+  $ cat > $TESTTMP/absextroot/relimportee.py <<EOF
+  > detail = "this is absextroot.relimportee"
+  > EOF
+  $ cat > $TESTTMP/absextroot/xsub1/xsub2/relimporter.py <<EOF
+  > from __future__ import absolute_import
+  > from ... import relimportee
+  > detail = "this relimporter imports %r" % (relimportee.detail)
+  > EOF
+
+Setup modules, which actually import extension local modules at
+runtime.
+
+  $ cat > $TESTTMP/absextroot/absolute.py << EOF
+  > from __future__ import absolute_import
+  > 
+  > # import extension local modules absolutely (level = 0)
+  > from absextroot.xsub1.xsub2 import used, unused
+  > from absextroot.xsub1.xsub2.called import func
+  > 
+  > def getresult():
+  >     result = []
+  >     result.append(used.detail)
+  >     result.append(func())
+  >     return result
+  > EOF
+
+  $ cat > $TESTTMP/absextroot/relative.py << EOF
+  > from __future__ import absolute_import
+  > 
+  > # import extension local modules relatively (level == 1)
+  > from .xsub1.xsub2 import used, unused
+  > from .xsub1.xsub2.called import func
+  > 
+  > # import a module, which implies "importing with level > 1"
+  > from .xsub1.xsub2 import relimporter
+  > 
+  > def getresult():
+  >     result = []
+  >     result.append(used.detail)
+  >     result.append(func())
+  >     result.append(relimporter.detail)
+  >     return result
+  > EOF
+
+Setup main procedure of extension.
+
+  $ cat > $TESTTMP/absextroot/__init__.py <<EOF
+  > from __future__ import absolute_import
+  > from mercurial import cmdutil
+  > cmdtable = {}
+  > command = cmdutil.command(cmdtable)
+  > 
+  > # "absolute" and "relative" shouldn't be imported before actual
+  > # command execution, because (1) they import same modules, and (2)
+  > # preceding import (= instantiate "demandmod" object instead of
+  > # real "module" object) might hide problem of succeeding import.
+  > 
+  > @command('showabsolute', [], norepo=True)
+  > def showabsolute(ui, *args, **opts):
+  >     from absextroot import absolute
+  >     ui.write('ABS: %s\n' % '\nABS: '.join(absolute.getresult()))
+  > 
+  > @command('showrelative', [], norepo=True)
+  > def showrelative(ui, *args, **opts):
+  >     from . import relative
+  >     ui.write('REL: %s\n' % '\nREL: '.join(relative.getresult()))
+  > 
+  > # import modules from external library
+  > from extlibroot.lsub1.lsub2 import used as lused, unused as lunused
+  > from extlibroot.lsub1.lsub2.called import func as lfunc
+  > from extlibroot.recursedown import absdetail, legacydetail
+  > 
+  > def uisetup(ui):
+  >     result = []
+  >     result.append(lused.detail)
+  >     result.append(lfunc())
+  >     result.append(absdetail)
+  >     result.append(legacydetail)
+  >     ui.write('LIB: %s\n' % '\nLIB: '.join(result))
+  > EOF
+
+Examine module importing.
+
+  $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.absextroot=$TESTTMP/absextroot showabsolute)
+  LIB: this is extlibroot.lsub1.lsub2.used
+  LIB: this is extlibroot.lsub1.lsub2.called.func()
+  LIB: this is extlibroot.recursedown.abs.used
+  LIB: this is extlibroot.recursedown.legacy.used
+  ABS: this is absextroot.xsub1.xsub2.used
+  ABS: this is absextroot.xsub1.xsub2.called.func()
+
+  $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.absextroot=$TESTTMP/absextroot showrelative)
+  LIB: this is extlibroot.lsub1.lsub2.used
+  LIB: this is extlibroot.lsub1.lsub2.called.func()
+  LIB: this is extlibroot.recursedown.abs.used
+  LIB: this is extlibroot.recursedown.legacy.used
+  REL: this is absextroot.xsub1.xsub2.used
+  REL: this is absextroot.xsub1.xsub2.called.func()
+  REL: this relimporter imports 'this is absextroot.relimportee'
+
+#endif
+
   $ cd ..
 
 hide outer repo
   $ hg init
 
   $ cat > empty.py <<EOF
   > '''empty cmdtable
   > '''
   > cmdtable = {}
   > EOF
   $ emptypath=`pwd`/empty.py
   $ echo "empty = $emptypath" >> $HGRCPATH
   $ hg help empty
   empty extension - empty cmdtable
   
   no commands defined
 
 
   $ echo 'empty = !' >> $HGRCPATH
 
   $ cat > debugextension.py <<EOF
   > '''only debugcommands
   > '''
   > from mercurial import cmdutil
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > @command('debugfoobar', [], 'hg debugfoobar')
   > def debugfoobar(ui, repo, *args, **opts):
   >     "yet another debug command"
   >     pass
   > @command('foo', [], 'hg foo')
   > def foo(ui, repo, *args, **opts):
   >     """yet another foo command
   >     This command has been DEPRECATED since forever.
   >     """
   >     pass
   > EOF
   $ debugpath=`pwd`/debugextension.py
   $ echo "debugextension = $debugpath" >> $HGRCPATH
 
   $ hg help debugextension
   hg debugextensions
   
   show information about active extensions
   
   options:
   
   (some details hidden, use --verbose to show complete help)
 
 
   $ hg --verbose help debugextension
   hg debugextensions
   
   show information about active extensions
   
   options:
   
    -T --template TEMPLATE display with template (EXPERIMENTAL)
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
 
 
 
 
 
 
   $ hg --debug help debugextension
   hg debugextensions
   
   show information about active extensions
   
   options:
   
    -T --template TEMPLATE display with template (EXPERIMENTAL)
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
 
 
 
 
 
   $ echo 'debugextension = !' >> $HGRCPATH
 
 Asking for help about a deprecated extension should do something useful:
 
   $ hg help glog
   'glog' is provided by the following extension:
   
       graphlog      command to view revision graphs from a shell (DEPRECATED)
   
   (use "hg help extensions" for information on enabling extensions)
 
 Extension module help vs command help:
 
   $ echo 'extdiff =' >> $HGRCPATH
   $ hg help extdiff
   hg extdiff [OPT]... [FILE]...
   
   use external program to diff repository (or selected files)
   
       Show differences between revisions for the specified files, using an
       external program. The default program used is diff, with default options
       "-Npru".
   
       To select a different program, use the -p/--program option. The program
       will be passed the names of two directories to compare. To pass additional
       options to the program, use -o/--option. These will be passed before the
       names of the directories to compare.
   
       When two revision arguments are given, then changes are shown between
       those revisions. If only one revision is specified then that revision is
       compared to the working directory, and, when no revisions are specified,
       the working directory files are compared to its parent.
   
   (use "hg help -e extdiff" to show help for the extdiff extension)
   
   options ([+] can be repeated):
   
    -p --program CMD         comparison program to run
    -o --option OPT [+]      pass option to comparison program
    -r --rev REV [+]         revision
    -c --change REV          change made by revision
       --patch               compare patches for two revisions
    -I --include PATTERN [+] include names matching the given patterns
    -X --exclude PATTERN [+] exclude names matching the given patterns
    -S --subrepos            recurse into subrepositories
   
   (some details hidden, use --verbose to show complete help)
 
 
 
 
 
 
 
 
 
 
   $ hg help --extension extdiff
   extdiff extension - command to allow external programs to compare revisions
   
   The extdiff Mercurial extension allows you to use external programs to compare
   revisions, or revision with working directory. The external diff programs are
   called with a configurable set of options and two non-option arguments: paths
   to directories containing snapshots of files to compare.
   
   The extdiff extension also allows you to configure new diff commands, so you
   do not need to type 'hg extdiff -p kdiff3' always.
   
     [extdiff]
     # add new command that runs GNU diff(1) in 'context diff' mode
     cdiff = gdiff -Nprc5
     ## or the old way:
     #cmd.cdiff = gdiff
     #opts.cdiff = -Nprc5
   
     # add new command called meld, runs meld (no need to name twice).  If
     # the meld executable is not available, the meld tool in [merge-tools]
     # will be used, if available
     meld =
   
     # add new command called vimdiff, runs gvimdiff with DirDiff plugin
     # (see http://www.vim.org/scripts/script.php?script_id=102) Non
     # English user, be sure to put "let g:DirDiffDynamicDiffText = 1" in
     # your .vimrc
     vimdiff = gvim -f "+next" \
               "+execute 'DirDiff' fnameescape(argv(0)) fnameescape(argv(1))"
   
   Tool arguments can include variables that are expanded at runtime:
   
     $parent1, $plabel1 - filename, descriptive label of first parent
     $child,   $clabel  - filename, descriptive label of child revision
     $parent2, $plabel2 - filename, descriptive label of second parent
     $root              - repository root
     $parent is an alias for $parent1.
   
   The extdiff extension will look in your [diff-tools] and [merge-tools]
   sections for diff tool arguments, when none are specified in [extdiff].
   
     [extdiff]
     kdiff3 =
   
     [diff-tools]
     kdiff3.diffargs=--L1 '$plabel1' --L2 '$clabel' $parent $child
   
   You can use -I/-X and list of file or directory names like normal 'hg diff'
   command. The extdiff extension makes snapshots of only needed files, so
   running the external diff program will actually be pretty fast (at least
   faster than having to compare the entire tree).
   
   list of commands:
   
    extdiff       use external program to diff repository (or selected files)
   
   (use "hg help -v -e extdiff" to show built-in aliases and global options)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   $ echo 'extdiff = !' >> $HGRCPATH
 
 Test help topic with same name as extension
 
   $ cat > multirevs.py <<EOF
   > from mercurial import cmdutil, commands
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > """multirevs extension
   > Big multi-line module docstring."""
   > @command('multirevs', [], 'ARG', norepo=True)
   > def multirevs(ui, repo, arg, *args, **opts):
   >     """multirevs command"""
   >     pass
   > EOF
   $ echo "multirevs = multirevs.py" >> $HGRCPATH
 
   $ hg help multirevs
   Specifying Multiple Revisions
   """""""""""""""""""""""""""""
   
       When Mercurial accepts more than one revision, they may be specified
       individually, or provided as a topologically continuous range, separated
       by the ":" character.
   
       The syntax of range notation is [BEGIN]:[END], where BEGIN and END are
       revision identifiers. Both BEGIN and END are optional. If BEGIN is not
       specified, it defaults to revision number 0. If END is not specified, it
       defaults to the tip. The range ":" thus means "all revisions".
   
       If BEGIN is greater than END, revisions are treated in reverse order.
   
       A range acts as a closed interval. This means that a range of 3:5 gives 3,
       4 and 5. Similarly, a range of 9:6 gives 9, 8, 7, and 6.
   
   use "hg help -c multirevs" to see help for the multirevs command
 
 
 
 
 
 
   $ hg help -c multirevs
   hg multirevs ARG
   
   multirevs command
   
   (some details hidden, use --verbose to show complete help)
 
 
 
   $ hg multirevs
   hg multirevs: invalid arguments
   hg multirevs ARG
   
   multirevs command
   
   (use "hg multirevs -h" to show more help)
   [255]
 
 
 
   $ echo "multirevs = !" >> $HGRCPATH
 
 Issue811: Problem loading extensions twice (by site and by user)
 
   $ cat <<EOF >> $HGRCPATH
   > mq =
   > strip =
   > hgext.mq =
   > hgext/mq =
   > EOF
 
 Show extensions:
 (note that mq force load strip, also checking it's not loaded twice)
 
   $ hg debugextensions
   mq
   strip
 
 For extensions, which name matches one of its commands, help
 message should ask '-v -e' to get list of built-in aliases
 along with extension help itself
 
   $ mkdir $TESTTMP/d
   $ cat > $TESTTMP/d/dodo.py <<EOF
   > """
   > This is an awesome 'dodo' extension. It does nothing and
   > writes 'Foo foo'
   > """
   > from mercurial import cmdutil, commands
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > @command('dodo', [], 'hg dodo')
   > def dodo(ui, *args, **kwargs):
   >     """Does nothing"""
   >     ui.write("I do nothing. Yay\\n")
   > @command('foofoo', [], 'hg foofoo')
   > def foofoo(ui, *args, **kwargs):
   >     """Writes 'Foo foo'"""
   >     ui.write("Foo foo\\n")
   > EOF
   $ dodopath=$TESTTMP/d/dodo.py
 
   $ echo "dodo = $dodopath" >> $HGRCPATH
 
 Make sure that user is asked to enter '-v -e' to get list of built-in aliases
   $ hg help -e dodo
   dodo extension -
   
   This is an awesome 'dodo' extension. It does nothing and writes 'Foo foo'
   
   list of commands:
   
    dodo          Does nothing
    foofoo        Writes 'Foo foo'
   
   (use "hg help -v -e dodo" to show built-in aliases and global options)
 
 Make sure that '-v -e' prints list of built-in aliases along with
 extension help itself
   $ hg help -v -e dodo
   dodo extension -
   
   This is an awesome 'dodo' extension. It does nothing and writes 'Foo foo'
   
   list of commands:
   
    dodo          Does nothing
    foofoo        Writes 'Foo foo'
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
 
 Make sure that single '-v' option shows help and built-ins only for 'dodo' command
   $ hg help -v dodo
   hg dodo
   
   Does nothing
   
   (use "hg help -e dodo" to show help for the dodo extension)
   
   options:
   
     --mq operate on patch repository
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
 
 In case when extension name doesn't match any of its commands,
 help message should ask for '-v' to get list of built-in aliases
 along with extension help
   $ cat > $TESTTMP/d/dudu.py <<EOF
   > """
   > This is an awesome 'dudu' extension. It does something and
   > also writes 'Beep beep'
   > """
   > from mercurial import cmdutil, commands
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > @command('something', [], 'hg something')
   > def something(ui, *args, **kwargs):
   >     """Does something"""
   >     ui.write("I do something. Yaaay\\n")
   > @command('beep', [], 'hg beep')
   > def beep(ui, *args, **kwargs):
   >     """Writes 'Beep beep'"""
   >     ui.write("Beep beep\\n")
   > EOF
   $ dudupath=$TESTTMP/d/dudu.py
 
   $ echo "dudu = $dudupath" >> $HGRCPATH
 
   $ hg help -e dudu
   dudu extension -
   
   This is an awesome 'dudu' extension. It does something and also writes 'Beep
   beep'
   
   list of commands:
   
    beep          Writes 'Beep beep'
    something     Does something
   
   (use "hg help -v dudu" to show built-in aliases and global options)
 
 In case when extension name doesn't match any of its commands,
 help options '-v' and '-v -e' should be equivalent
   $ hg help -v dudu
   dudu extension -
   
   This is an awesome 'dudu' extension. It does something and also writes 'Beep
   beep'
   
   list of commands:
   
    beep          Writes 'Beep beep'
    something     Does something
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
 
   $ hg help -v -e dudu
   dudu extension -
   
   This is an awesome 'dudu' extension. It does something and also writes 'Beep
   beep'
   
   list of commands:
   
    beep          Writes 'Beep beep'
    something     Does something
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
 
 Disabled extension commands:
 
   $ ORGHGRCPATH=$HGRCPATH
   $ HGRCPATH=
   $ export HGRCPATH
   $ hg help email
   'email' is provided by the following extension:
   
       patchbomb     command to send changesets as (a series of) patch emails
   
   (use "hg help extensions" for information on enabling extensions)
 
 
   $ hg qdel
   hg: unknown command 'qdel'
   'qdelete' is provided by the following extension:
   
       mq            manage a stack of patches
   
   (use "hg help extensions" for information on enabling extensions)
   [255]
 
 
   $ hg churn
   hg: unknown command 'churn'
   'churn' is provided by the following extension:
   
       churn         command to display statistics about repository history
   
   (use "hg help extensions" for information on enabling extensions)
   [255]
 
 
 
 Disabled extensions:
 
   $ hg help churn
   churn extension - command to display statistics about repository history
   
   (use "hg help extensions" for information on enabling extensions)
 
   $ hg help patchbomb
   patchbomb extension - command to send changesets as (a series of) patch emails
   
   (use "hg help extensions" for information on enabling extensions)
 
 
 Broken disabled extension and command:
 
   $ mkdir hgext
   $ echo > hgext/__init__.py
   $ cat > hgext/broken.py <<EOF
   > "broken extension'
   > EOF
   $ cat > path.py <<EOF
   > import os, sys
   > sys.path.insert(0, os.environ['HGEXTPATH'])
   > EOF
   $ HGEXTPATH=`pwd`
   $ export HGEXTPATH
 
   $ hg --config extensions.path=./path.py help broken
   broken extension - (no help text available)
   
   (use "hg help extensions" for information on enabling extensions)
 
 
   $ cat > hgext/forest.py <<EOF
   > cmdtable = None
   > EOF
   $ hg --config extensions.path=./path.py help foo > /dev/null
   warning: error finding commands in $TESTTMP/hgext/forest.py (glob)
   abort: no such help topic: foo
   (try "hg help --keyword foo")
   [255]
 
   $ cat > throw.py <<EOF
   > from mercurial import cmdutil, commands, util
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > class Bogon(Exception): pass
   > @command('throw', [], 'hg throw', norepo=True)
   > def throw(ui, **opts):
   >     """throws an exception"""
   >     raise Bogon()
   > EOF
 
 No declared supported version, extension complains:
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions unknown of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM * (glob)
   ** Extensions loaded: throw
 
 empty declaration of supported version, extension complains:
   $ echo "testedwith = ''" >> throw.py
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions unknown of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 If the extension specifies a buglink, show that:
   $ echo 'buglink = "http://example.com/bts"' >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions unknown of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to http://example.com/bts
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 If the extensions declare outdated versions, accuse the older extension first:
   $ echo "from mercurial import util" >> older.py
   $ echo "util.version = lambda:'2.2'" >> older.py
   $ echo "testedwith = '1.9.3'" >> older.py
   $ echo "testedwith = '2.1.1'" >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension older
   ** which supports versions 1.9 of Mercurial.
   ** Please disable older and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM (version 2.2)
   ** Extensions loaded: throw, older
 
 One extension only tested with older, one only with newer versions:
   $ echo "util.version = lambda:'2.1'" >> older.py
   $ rm -f older.pyc older.pyo
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension older
   ** which supports versions 1.9 of Mercurial.
   ** Please disable older and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM (version 2.1)
   ** Extensions loaded: throw, older
 
 Older extension is tested with current version, the other only with newer:
   $ echo "util.version = lambda:'1.9.3'" >> older.py
   $ rm -f older.pyc older.pyo
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions 2.1 of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to http://example.com/bts
   ** Python * (glob)
   ** Mercurial Distributed SCM (version 1.9.3)
   ** Extensions loaded: throw, older
 
 Ability to point to a different point
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   --config ui.supportcontact='Your Local Goat Lenders' throw 2>&1 | egrep '^\*\*'
   ** unknown exception encountered, please report by visiting
   ** Your Local Goat Lenders
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw, older
 
 Declare the version as supporting this hg version, show regular bts link:
   $ hgver=`hg debuginstall -T '{hgver}'`
   $ echo 'testedwith = """'"$hgver"'"""' >> throw.py
   $ if [ -z "$hgver" ]; then
   >   echo "unable to fetch a mercurial version. Make sure __version__ is correct";
   > fi
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** unknown exception encountered, please report by visiting
   ** https://mercurial-scm.org/wiki/BugTracker
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 Patch version is ignored during compatibility check
   $ echo "testedwith = '3.2'" >> throw.py
   $ echo "util.version = lambda:'3.2.2'" >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** unknown exception encountered, please report by visiting
   ** https://mercurial-scm.org/wiki/BugTracker
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 Test version number support in 'hg version':
   $ echo '__version__ = (1, 2, 3)' >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg version -v
   Mercurial Distributed SCM (version *) (glob)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   
   Enabled extensions:
   
 
   $ hg version -v --config extensions.throw=throw.py
   Mercurial Distributed SCM (version *) (glob)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   
   Enabled extensions:
   
     throw  external  1.2.3
   $ echo 'getversion = lambda: "1.twentythree"' >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg version -v --config extensions.throw=throw.py
   Mercurial Distributed SCM (version *) (glob)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   
   Enabled extensions:
   
     throw  external  1.twentythree
 
 Refuse to load extensions with minimum version requirements
 
   $ cat > minversion1.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.5.2'
   > minimumhgversion = '3.6'
   > EOF
   $ hg --config extensions.minversion=minversion1.py version
   (third party extension minversion requires version 3.6 or newer of Mercurial; disabling)
   Mercurial Distributed SCM (version 3.5.2)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
   $ cat > minversion2.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.6'
   > minimumhgversion = '3.7'
   > EOF
   $ hg --config extensions.minversion=minversion2.py version 2>&1 | egrep '\(third'
   (third party extension minversion requires version 3.7 or newer of Mercurial; disabling)
 
 Can load version that is only off by point release
 
   $ cat > minversion2.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.6.1'
   > minimumhgversion = '3.6'
   > EOF
   $ hg --config extensions.minversion=minversion3.py version 2>&1 | egrep '\(third'
   [1]
 
 Can load minimum version identical to current
 
   $ cat > minversion3.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.5'
   > minimumhgversion = '3.5'
   > EOF
   $ hg --config extensions.minversion=minversion3.py version 2>&1 | egrep '\(third'
   [1]
 
 Restore HGRCPATH
 
   $ HGRCPATH=$ORGHGRCPATH
   $ export HGRCPATH
 
 Commands handling multiple repositories at a time should invoke only
 "reposetup()" of extensions enabling in the target repository.
 
   $ mkdir reposetup-test
   $ cd reposetup-test
 
   $ cat > $TESTTMP/reposetuptest.py <<EOF
   > from mercurial import extensions
   > def reposetup(ui, repo):
   >     ui.write('reposetup() for %s\n' % (repo.root))
   >     ui.flush()
   > EOF
   $ hg init src
   $ echo a > src/a
   $ hg -R src commit -Am '#0 at src/a'
   adding a
   $ echo '[extensions]' >> src/.hg/hgrc
   $ echo '# enable extension locally' >> src/.hg/hgrc
   $ echo "reposetuptest = $TESTTMP/reposetuptest.py" >> src/.hg/hgrc
   $ hg -R src status
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ hg clone -U src clone-dst1
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init push-dst1
   $ hg -q -R src push push-dst1
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init pull-src1
   $ hg -q -R pull-src1 pull src
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > # disable extension globally and explicitly
   > reposetuptest = !
   > EOF
   $ hg clone -U src clone-dst2
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init push-dst2
   $ hg -q -R src push push-dst2
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init pull-src2
   $ hg -q -R pull-src2 pull src
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > # enable extension globally
   > reposetuptest = $TESTTMP/reposetuptest.py
   > EOF
   $ hg clone -U src clone-dst3
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   reposetup() for $TESTTMP/reposetup-test/clone-dst3 (glob)
   $ hg init push-dst3
   reposetup() for $TESTTMP/reposetup-test/push-dst3 (glob)
   $ hg -q -R src push push-dst3
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   reposetup() for $TESTTMP/reposetup-test/push-dst3 (glob)
   $ hg init pull-src3
   reposetup() for $TESTTMP/reposetup-test/pull-src3 (glob)
   $ hg -q -R pull-src3 pull src
   reposetup() for $TESTTMP/reposetup-test/pull-src3 (glob)
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ echo '[extensions]' >> src/.hg/hgrc
   $ echo '# disable extension locally' >> src/.hg/hgrc
   $ echo 'reposetuptest = !' >> src/.hg/hgrc
   $ hg clone -U src clone-dst4
   reposetup() for $TESTTMP/reposetup-test/clone-dst4 (glob)
   $ hg init push-dst4
   reposetup() for $TESTTMP/reposetup-test/push-dst4 (glob)
   $ hg -q -R src push push-dst4
   reposetup() for $TESTTMP/reposetup-test/push-dst4 (glob)
   $ hg init pull-src4
   reposetup() for $TESTTMP/reposetup-test/pull-src4 (glob)
   $ hg -q -R pull-src4 pull src
   reposetup() for $TESTTMP/reposetup-test/pull-src4 (glob)
 
 disabling in command line overlays with all configuration
   $ hg --config extensions.reposetuptest=! clone -U src clone-dst5
   $ hg --config extensions.reposetuptest=! init push-dst5
   $ hg --config extensions.reposetuptest=! -q -R src push push-dst5
   $ hg --config extensions.reposetuptest=! init pull-src5
   $ hg --config extensions.reposetuptest=! -q -R pull-src5 pull src
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > # disable extension globally and explicitly
   > reposetuptest = !
   > EOF
   $ hg init parent
   $ hg init parent/sub1
   $ echo 1 > parent/sub1/1
   $ hg -R parent/sub1 commit -Am '#0 at parent/sub1'
   adding 1
   $ hg init parent/sub2
   $ hg init parent/sub2/sub21
   $ echo 21 > parent/sub2/sub21/21
   $ hg -R parent/sub2/sub21 commit -Am '#0 at parent/sub2/sub21'
   adding 21
   $ cat > parent/sub2/.hgsub <<EOF
   > sub21 = sub21
   > EOF
   $ hg -R parent/sub2 commit -Am '#0 at parent/sub2'
   adding .hgsub
   $ hg init parent/sub3
   $ echo 3 > parent/sub3/3
   $ hg -R parent/sub3 commit -Am '#0 at parent/sub3'
   adding 3
   $ cat > parent/.hgsub <<EOF
   > sub1 = sub1
   > sub2 = sub2
   > sub3 = sub3
   > EOF
   $ hg -R parent commit -Am '#0 at parent'
   adding .hgsub
   $ echo '[extensions]' >> parent/.hg/hgrc
   $ echo '# enable extension locally' >> parent/.hg/hgrc
   $ echo "reposetuptest = $TESTTMP/reposetuptest.py" >> parent/.hg/hgrc
   $ cp parent/.hg/hgrc parent/sub2/.hg/hgrc
   $ hg -R parent status -S -A
   reposetup() for $TESTTMP/reposetup-test/parent (glob)
   reposetup() for $TESTTMP/reposetup-test/parent/sub2 (glob)
   C .hgsub
   C .hgsubstate
   C sub1/1
   C sub2/.hgsub
   C sub2/.hgsubstate
   C sub2/sub21/21
   C sub3/3
 
   $ cd ..
 
 Test compatibility with extension commands that don't use @command (issue5137)
 
   $ hg init deprecated
   $ cd deprecated
 
   $ cat <<EOF > deprecatedcmd.py
   > def deprecatedcmd(repo, ui):
   >     pass
   > cmdtable = {
   >     'deprecatedcmd': (deprecatedcmd, [], ''),
   > }
   > EOF
   $ cat <<EOF > .hg/hgrc
   > [extensions]
   > deprecatedcmd = `pwd`/deprecatedcmd.py
   > mq = !
   > hgext.mq = !
   > hgext/mq = !
   > [alias]
   > deprecatedalias = deprecatedcmd
   > EOF
 
   $ hg deprecatedcmd
   devel-warn: missing attribute 'norepo', use @command decorator to register 'deprecatedcmd'
   (compatibility will be dropped after Mercurial-3.8, update your code.) at: * (glob)
 
   $ hg deprecatedalias
   devel-warn: missing attribute 'norepo', use @command decorator to register 'deprecatedalias'
   (compatibility will be dropped after Mercurial-3.8, update your code.) at: * (glob)
 
  no warning unless command is executed:
 
   $ hg paths
 
  but mq iterates over command table:
 
   $ hg --config extensions.mq= paths
   devel-warn: missing attribute 'norepo', use @command decorator to register 'deprecatedcmd'
   (compatibility will be dropped after Mercurial-3.8, update your code.) at: * (glob)
 
   $ cd ..
 
 Test synopsis and docstring extending
 
   $ hg init exthelp
   $ cat > exthelp.py <<EOF
   > from mercurial import commands, extensions
   > def exbookmarks(orig, *args, **opts):
   >     return orig(*args, **opts)
   > def uisetup(ui):
   >     synopsis = ' GREPME [--foo] [-x]'
   >     docstring = '''
   >     GREPME make sure that this is in the help!
   >     '''
   >     extensions.wrapcommand(commands.table, 'bookmarks', exbookmarks,
   >                            synopsis, docstring)
   > EOF
   $ abspath=`pwd`/exthelp.py
   $ echo '[extensions]' >> $HGRCPATH
   $ echo "exthelp = $abspath" >> $HGRCPATH
   $ cd exthelp
   $ hg help bookmarks | grep GREPME
   hg bookmarks [OPTIONS]... [NAME]... GREPME [--foo] [-x]
       GREPME make sure that this is in the help!