alias: only allow global options before a shell alias, pass later ones through

This patch refactors the dispatch code to change how arguments to shell aliases
are handled.

A separate "pass" to determine whether a command is a shell alias has been
added. The rough steps dispatch now performs when a command is given are these:

* Parse all arguments up to the command name.

* If any arguments such as --repository or --cwd are given (which could change
  the config file used, and therefore the definition of aliases), they are
  taken into account.

* We determine whether the command is a shell alias.

    * If so, execute the alias. The --repo and --cwd arguments are still in effect.
      Any arguments *after* the command name are passed unchanged through to the
      shell command (and interpolated as normal.

    * If the command is *not* a shell alias, the dispatching is effectively "reset"
      and reparsed as normal in its entirety.

The net effect of this patch is to make shell alias commands behave as you
would expect.

Any arguments you give to a shell alias *after* the alias name are passed
through unchanged. This lets you do something like the following:

    [alias]
    filereleased = !$HG log -r 'descendants(adds("$1")) and tagged()' -l1 $2 $3 $4 $5

    $ hg filereleased hgext/bookmarks.py --style compact

Previously the `--style compact` part would fail because Mercurial would
interpret those arguments as arguments to the alias command itself (which
doesn't take any arguments).

Also: running something like `hg -R ~/src/hg-crew filereleased
hgext/bookmarks.py` when `filereleased` is only defined in that repo's config
will now work.

These global arguments can *only* be given to a shell alias *before* the alias
name.  For example, this will *not* work in the above situation:

    $ hg filereleased -R ~/src/hg-crew hgext/bookmarks.py

The reason for this is that you may want to pass arguments like --repository to
the alias (or, more likely, their short versions like -R):

    [alias]
    own = !chown $@ `$HG root`

    $ hg own steve
    $ hg own -R steve

mercurial/dispatch.py

@@ -218,6 +218,7 b' class cmdalias(object):'
             return
 
         if self.definition.startswith('!'):
+            self.shell = True
             def fn(ui, *args):
                 env = {'HG_ARGS': ' '.join((self.name,) + args)}
                 def _checkvar(m):
@@ -404,18 +405,11 b' def runcommand(lui, repo, cmd, fullargs,'
               result=ret, pats=cmdpats, opts=cmdoptions)
     return ret
 
-_loaded = set()
-def _dispatch(ui, args):
-    # read --config before doing anything else
-    # (e.g. to change trust settings for reading .hg/hgrc)
-    _parseconfig(ui, _earlygetopt(['--config'], args))
-
-    # check for cwd
-    cwd = _earlygetopt(['--cwd'], args)
-    if cwd:
-        os.chdir(cwd[-1])
-
-    # read the local repository .hgrc into a local ui object
+def _getlocal(ui, rpath):
+    """Return (path, local ui object) for the given target path.
+    
+    Takes paths in [cwd]/.hg/hgrc into account."
+    """
     try:
         wd = os.getcwd()
     except OSError, e:
@@ -431,13 +425,64 b' def _dispatch(ui, args):'
         except IOError:
             pass
 
-    # now we can expand paths, even ones in .hg/hgrc
-    rpath = _earlygetopt(["-R", "--repository", "--repo"], args)
     if rpath:
         path = lui.expandpath(rpath[-1])
         lui = ui.copy()
         lui.readconfig(os.path.join(path, ".hg", "hgrc"))
 
+    return path, lui
+
+def _checkshellalias(ui, args):
+    cwd = os.getcwd()
+    options = {}
+    args = fancyopts.fancyopts(args, commands.globalopts, options)
+
+    if not args:
+        return
+
+    _parseconfig(ui, options['config'])
+    if options['cwd']:
+        os.chdir(options['cwd'])
+
+    path, lui = _getlocal(ui, [options['repository']])
+
+    cmdtable = commands.table.copy()
+    addaliases(lui, cmdtable)
+
+    cmd = args[0]
+    try:
+        aliases, entry = cmdutil.findcmd(cmd, cmdtable, lui.config("ui", "strict"))
+    except error.UnknownCommand:
+        os.chdir(cwd)
+        return
+
+    cmd = aliases[0]
+    fn = entry[0]
+
+    if cmd and hasattr(fn, 'shell'):
+        d = lambda: fn(ui, *args[1:])
+        return lambda: runcommand(lui, None, cmd, args[:1], ui, options, d, [], {})
+
+    os.chdir(cwd)
+
+_loaded = set()
+def _dispatch(ui, args):
+    shellaliasfn = _checkshellalias(ui, args)
+    if shellaliasfn:
+        return shellaliasfn()
+
+    # read --config before doing anything else
+    # (e.g. to change trust settings for reading .hg/hgrc)
+    _parseconfig(ui, _earlygetopt(['--config'], args))
+
+    # check for cwd
+    cwd = _earlygetopt(['--cwd'], args)
+    if cwd:
+        os.chdir(cwd[-1])
+
+    rpath = _earlygetopt(["-R", "--repository", "--repo"], args)
+    path, lui = _getlocal(ui, rpath)
+
     # Configure extensions in phases: uisetup, extsetup, cmdtable, and
     # reposetup. Programs like TortoiseHg will call _dispatch several
     # times so we keep track of configured extensions in _loaded.

tests/test-alias.t

@@ -23,6 +23,7 b''
   > echo2 = !echo '\$2'
   > echo13 = !echo '\$1' '\$3'
   > count = !hg log -r '\$@' --template='.' | wc -c | sed -e 's/ //g'
+  > mcount = !hg log \$@ --template='.' | wc -c | sed -e 's/ //g'
   > rt = root
   > 
   > [defaults]
@@ -158,10 +159,10 b' simple shell aliases'
   
   $ hg blank foo
   
+  $ hg self
+  self
   $ hg echo
   
-  $ hg self
-  self
   $ hg echo foo
   foo
   $ hg echo 'test $2' foo
@@ -180,6 +181,59 b' simple shell aliases'
   1
   $ hg count 'branch(default)'
   2
+  $ hg mcount -r '"branch(default)"'
+  2
+
+
+shell aliases with global options
+
+  $ hg init sub
+  $ cd sub
+  $ hg count 'branch(default)'
+  0
+  $ hg -v count 'branch(default)'
+  0
+  $ hg -R .. count 'branch(default)'
+  0
+  $ hg --cwd .. count 'branch(default)'
+  2
+  $ hg echo --cwd ..
+  --cwd ..
+
+
+repo specific shell aliases
+
+  $ cat >> .hg/hgrc <<EOF
+  > [alias]
+  > subalias = !echo sub \$@
+  > EOF
+  $ cat >> ../.hg/hgrc <<EOF
+  > [alias]
+  > mainalias = !echo main \$@
+  > EOF
+
+
+shell alias defined in current repo
+
+  $ hg subalias
+  sub
+  $ hg --cwd .. subalias > /dev/null
+  hg: unknown command 'subalias'
+  [255]
+  $ hg -R .. subalias > /dev/null
+  hg: unknown command 'subalias'
+  [255]
+
+
+shell alias defined in other repo
+
+  $ hg mainalias > /dev/null
+  hg: unknown command 'mainalias'
+  [255]
+  $ hg -R .. mainalias
+  main
+  $ hg --cwd .. mainalias
+  main
 
 
 invalid arguments