hook: for python hooks, also return whether an exception was raised

The hook code treats python hooks raising an exception and returning True as
the exact same. This is OK for hooks themselves, but other code that wants to
invoke external code using the same underlying code is a bit more interested in
making a distinction.

mercurial/hook.py

@@ -1,226 +1,228 b''
 # hook.py - hook support for mercurial
 #
 # Copyright 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.
 
 from __future__ import absolute_import
 
 import os
 import sys
 import time
 
 from .i18n import _
 from . import (
     demandimport,
     error,
     extensions,
     util,
 )
 
 def _pythonhook(ui, repo, name, hname, funcname, args, throw):
     '''call python hook. hook is callable object, looked up as
     name in python module. if callable returns "true", hook
     fails, else passes. if hook raises exception, treated as
     hook failure. exception propagates if throw is "true".
 
     reason for "true" meaning "hook failed" is so that
     unmodified commands (e.g. mercurial.commands.update) can
     be run as hooks without wrappers to convert return values.'''
 
     if callable(funcname):
         obj = funcname
         funcname = obj.__module__ + "." + obj.__name__
     else:
         d = funcname.rfind('.')
         if d == -1:
             raise error.HookLoadError(
                 _('%s hook is invalid ("%s" not in a module)')
                 % (hname, funcname))
         modname = funcname[:d]
         oldpaths = sys.path
         if util.mainfrozen():
             # binary installs require sys.path manipulation
             modpath, modfile = os.path.split(modname)
             if modpath and modfile:
                 sys.path = sys.path[:] + [modpath]
                 modname = modfile
         with demandimport.deactivated():
             try:
                 obj = __import__(modname)
             except ImportError:
                 e1 = sys.exc_type, sys.exc_value, sys.exc_traceback
                 try:
                     # extensions are loaded with hgext_ prefix
                     obj = __import__("hgext_%s" % modname)
                 except ImportError:
                     e2 = sys.exc_type, sys.exc_value, sys.exc_traceback
                     if ui.tracebackflag:
                         ui.warn(_('exception from first failed import '
                                   'attempt:\n'))
                     ui.traceback(e1)
                     if ui.tracebackflag:
                         ui.warn(_('exception from second failed import '
                                   'attempt:\n'))
                     ui.traceback(e2)
                     raise error.HookLoadError(
                         _('%s hook is invalid (import of "%s" failed)') %
                         (hname, modname))
         sys.path = oldpaths
         try:
             for p in funcname.split('.')[1:]:
                 obj = getattr(obj, p)
         except AttributeError:
             raise error.HookLoadError(
                 _('%s hook is invalid ("%s" is not defined)')
                 % (hname, funcname))
         if not callable(obj):
             raise error.HookLoadError(
                 _('%s hook is invalid ("%s" is not callable)')
                 % (hname, funcname))
 
     ui.note(_("calling hook %s: %s\n") % (hname, funcname))
     starttime = time.time()
 
     try:
         # redirect IO descriptors to the ui descriptors so hooks
         # that write directly to these don't mess up the command
         # protocol when running through the command server
         old = sys.stdout, sys.stderr, sys.stdin
         sys.stdout, sys.stderr, sys.stdin = ui.fout, ui.ferr, ui.fin
 
         r = obj(ui=ui, repo=repo, hooktype=name, **args)
     except Exception as exc:
         if isinstance(exc, error.Abort):
             ui.warn(_('error: %s hook failed: %s\n') %
                          (hname, exc.args[0]))
         else:
             ui.warn(_('error: %s hook raised an exception: '
                            '%s\n') % (hname, exc))
         if throw:
             raise
         ui.traceback()
-        return True
+        return True, True
     finally:
         sys.stdout, sys.stderr, sys.stdin = old
         duration = time.time() - starttime
         ui.log('pythonhook', 'pythonhook-%s: %s finished in %0.2f seconds\n',
                name, funcname, duration)
     if r:
         if throw:
             raise error.HookAbort(_('%s hook failed') % hname)
         ui.warn(_('warning: %s hook failed\n') % hname)
-    return r
+    return r, False
 
 def _exthook(ui, repo, name, cmd, args, throw):
     ui.note(_("running hook %s: %s\n") % (name, cmd))
 
     starttime = time.time()
     env = {}
     for k, v in args.iteritems():
         if callable(v):
             v = v()
         if isinstance(v, dict):
             # make the dictionary element order stable across Python
             # implementations
             v = ('{' +
                  ', '.join('%r: %r' % i for i in sorted(v.iteritems())) +
                  '}')
         env['HG_' + k.upper()] = v
 
     if repo:
         cwd = repo.root
     else:
         cwd = os.getcwd()
     r = ui.system(cmd, environ=env, cwd=cwd)
 
     duration = time.time() - starttime
     ui.log('exthook', 'exthook-%s: %s finished in %0.2f seconds\n',
            name, cmd, duration)
     if r:
         desc, r = util.explainexit(r)
         if throw:
             raise error.HookAbort(_('%s hook %s') % (name, desc))
         ui.warn(_('warning: %s hook %s\n') % (name, desc))
     return r
 
 def _allhooks(ui):
     hooks = []
     for name, cmd in ui.configitems('hooks'):
         if not name.startswith('priority'):
             priority = ui.configint('hooks', 'priority.%s' % name, 0)
             hooks.append((-priority, len(hooks), name, cmd))
     return [(k, v) for p, o, k, v in sorted(hooks)]
 
 _redirect = False
 def redirect(state):
     global _redirect
     _redirect = state
 
 def hook(ui, repo, name, throw=False, **args):
     if not ui.callhooks:
         return False
 
     hooks = []
     for hname, cmd in _allhooks(ui):
         if hname.split('.')[0] == name and cmd:
             hooks.append((hname, cmd))
 
     res = runhooks(ui, repo, name, hooks, throw=throw, **args)
     r = False
     for hname, cmd in hooks:
-        r = res[hname] or r
+        r = res[hname][0] or r
     return r
 
 def runhooks(ui, repo, name, hooks, throw=False, **args):
     res = {}
     oldstdout = -1
 
     try:
         for hname, cmd in hooks:
             if oldstdout == -1 and _redirect:
                 try:
                     stdoutno = sys.__stdout__.fileno()
                     stderrno = sys.__stderr__.fileno()
                     # temporarily redirect stdout to stderr, if possible
                     if stdoutno >= 0 and stderrno >= 0:
                         sys.__stdout__.flush()
                         oldstdout = os.dup(stdoutno)
                         os.dup2(stderrno, stdoutno)
                 except (OSError, AttributeError):
                     # files seem to be bogus, give up on redirecting (WSGI, etc)
                     pass
 
             if callable(cmd):
-                r = _pythonhook(ui, repo, name, hname, cmd, args, throw)
+                r, raised = _pythonhook(ui, repo, name, hname, cmd, args, throw)
             elif cmd.startswith('python:'):
                 if cmd.count(':') >= 2:
                     path, cmd = cmd[7:].rsplit(':', 1)
                     path = util.expandpath(path)
                     if repo:
                         path = os.path.join(repo.root, path)
                     try:
                         mod = extensions.loadpath(path, 'hghook.%s' % hname)
                     except Exception:
                         ui.write(_("loading %s hook failed:\n") % hname)
                         raise
                     hookfn = getattr(mod, cmd)
                 else:
                     hookfn = cmd[7:].strip()
-                r = _pythonhook(ui, repo, name, hname, hookfn, args, throw)
+                r, raised = _pythonhook(ui, repo, name, hname, hookfn, args,
+                                        throw)
             else:
                 r = _exthook(ui, repo, hname, cmd, args, throw)
+                raised = False
 
-            res[hname] = r
+            res[hname] = r, raised
 
             # The stderr is fully buffered on Windows when connected to a pipe.
             # A forcible flush is required to make small stderr data in the
             # remote side available to the client immediately.
             sys.stderr.flush()
     finally:
         if _redirect and oldstdout >= 0:
             os.dup2(oldstdout, stdoutno)
             os.close(oldstdout)
 
     return res