[PATCH WIP] help: show help content for disabled extension

[liscju]

# HG changeset patch
# User liscju <piotr.listkiewicz at gmail.com>
# Date 1475926049 -7200
#      Sat Oct 08 13:27:29 2016 +0200
# Node ID 5497a92be82db414f6913f869d5acd18b205cb2b
# Parent  91a3c58ecf938ed675f5364b88f0d663f12b0047
help: show help content for disabled extension

So far for disabled extension help showed only extension
summary. This commit makes help read content of the help
comments in extension module without actually loading
the module.

diff --git a/mercurial/help.py b/mercurial/help.py
--- a/mercurial/help.py
+++ b/mercurial/help.py
@@ -7,6 +7,7 @@
 
 from __future__ import absolute_import
 
+import ast
 import itertools
 import os
 import textwrap
@@ -300,6 +301,38 @@ addtopicsymbols('templates', '.. functio
 addtopicsymbols('hgweb', '.. webcommandsmarker', webcommands.commands,
                 dedent=True)
 
+def parsedisabledext(modname):
+    # return list of (command_name, command_module, command_doc)
+    def finddisabledext(name):
+        paths = extensions._disabledpaths()
+        if name in paths:
+            return paths[name]
+        return None
+
+    def iscmd(funast):
+        for decorator in funast.decorator_list:
+            if isinstance(decorator, ast.Call) and decorator.func.id == 'command':
+                return True
+        return False
+
+    def extractcmds(extast):
+        return [funast.name for funast in extast.body if isinstance(funast, ast.FunctionDef) and iscmd(funast)]
+
+    def extractcmddoc(extast, cmd):
+        funasts = [funast for funast in extast.body
+                  if isinstance(funast, ast.FunctionDef) and iscmd(funast) and funast.name == cmd]
+        if len(funasts) > 0:
+            return ast.get_docstring(funasts[0])
+        else:
+            return None
+
+    extfile = open(finddisabledext(modname), 'r')
+    try:
+        extast = ast.parse(extfile.read())
+        return [(cmdname, modname, extractcmddoc(extast, cmdname)) for cmdname in extractcmds(extast)]
+    except SyntaxError:
+        return []
+
 def help_(ui, name, unknowncmd=False, full=True, subtopic=None, **opts):
     '''
     Generate the help for 'name' as unformatted restructured text. If
@@ -395,7 +428,7 @@ def help_(ui, name, unknowncmd=False, fu
         return rst
 
 
-    def helplist(select=None, **opts):
+    def helplist(select=None, disabledext=None, **opts):
         # list of commands
         if name == "shortlist":
             header = _('basic commands:\n\n')
@@ -406,17 +439,24 @@ def help_(ui, name, unknowncmd=False, fu
 
         h = {}
         cmds = {}
-        for c, e in commands.table.iteritems():
+
+        if not disabledext:
+            commandinfos = [(c, e[0].__module__, e[0].__doc__) for c, e in commands.table.iteritems()]
+        else:
+            commandinfos = parsedisabledext(disabledext)
+
+        for cmdname, cmdmod, cmddoc in commandinfos:
+            c = cmdname
             f = c.partition("|")[0]
             if select and not select(f):
                 continue
             if (not select and name != 'shortlist' and
-                e[0].__module__ != commands.__name__):
+                cmdmod != commands.__name__):
                 continue
             if name == "shortlist" and not f.startswith("^"):
                 continue
             f = f.lstrip("^")
-            doc = e[0].__doc__
+            doc = cmddoc
             if filtercmd(ui, f, name, doc):
                 continue
             doc = gettext(doc)
@@ -548,7 +588,8 @@ def help_(ui, name, unknowncmd=False, fu
             modcmds = set([c.partition('|')[0] for c in ct])
             rst.extend(helplist(modcmds.__contains__))
         else:
-            rst.append(_("(use 'hg help extensions' for information on enabling"
+            rst.extend(helplist(lambda w: True, disabledext=name))
+            rst.append(_("\n(use 'hg help extensions' for information on enabling"
                        " extensions)\n"))
         return rst
 
diff --git a/tests/test-extension.t b/tests/test-extension.t
--- a/tests/test-extension.t
+++ b/tests/test-extension.t
@@ -1040,11 +1040,23 @@ Disabled extensions:
   $ hg help churn
   churn extension - command to display statistics about repository history
   
+  list of commands:
+  
+   churn         histogram of changes to the repository
+  
+  (use 'hg help -v -e churn' to show built-in aliases and global options)
+  
   (use 'hg help extensions' for information on enabling extensions)
 
   $ hg help patchbomb
   patchbomb extension - command to send changesets as (a series of) patch emails
   
+  list of commands:
+  
+   email         send changesets by email
+  
+  (use 'hg help -v patchbomb' to show built-in aliases and global options)
+  
   (use 'hg help extensions' for information on enabling extensions)
 
 
@@ -1065,6 +1077,8 @@ Broken disabled extension and command:
   $ hg --config extensions.path=./path.py help broken
   broken extension - (no help text available)
   
+  no commands defined
+  
   (use 'hg help extensions' for information on enabling extensions)
 
 
diff --git a/tests/test-help.t b/tests/test-help.t
--- a/tests/test-help.t
+++ b/tests/test-help.t
@@ -1636,6 +1636,8 @@ Show help content of disabled extensions
   $ hg help -e ambiguous
   ambiguous extension - (no help text available)
   
+  no commands defined
+  
   (use 'hg help extensions' for information on enabling extensions)
 
 Test dynamic list of merge tools only shows up once
diff --git a/tests/test-qrecord.t b/tests/test-qrecord.t
--- a/tests/test-qrecord.t
+++ b/tests/test-qrecord.t
@@ -9,6 +9,13 @@ help record (no record)
   record extension - commands to interactively select changes for
   commit/qrefresh (DEPRECATED)
   
+  list of commands:
+  
+   qrecord       interactively record a new patch
+   record        interactively select changes to commit
+  
+  (use 'hg help -v -e record' to show built-in aliases and global options)
+  
   (use 'hg help extensions' for information on enabling extensions)
 
 help qrecord (no record)