dispatch: load shared source repository config in share-safe mode

dispatch: load shared source repository config in share-safe mode

It seems to me now that there are two steps when config is loaded:

1) on dispatch
2) repository object creation

Recent patches added functionality that there can be shares in share-safe mode
where config of the source repository is shared with the the shares. However we
missed adding logic to read the source config on dispatch. This leads to
extensions not being loaded on dispatch and hence extensions command not being
recognized.

This patch fixes it by reading the shared source config on dispatch.

Differential Revision: https://phab.mercurial-scm.org/D9047

--- a/mercurial/dispatch.py	Fri Sep 18 17:28:22 2020 +0530
+++ b/mercurial/dispatch.py	Fri Sep 18 18:52:38 2020 +0530
@@ -36,13 +36,16 @@
     help,
     hg,
     hook,
+    localrepo,
     profiling,
     pycompat,
     rcutil,
     registrar,
+    requirements as requirementsmod,
     scmutil,
     ui as uimod,
     util,
+    vfs,
 )
 
 from .utils import (
@@ -939,6 +942,29 @@
     return ret
 
 
+def _readsharedsourceconfig(ui, path):
+    """if the current repository is shared one, this tries to read
+    .hg/hgrc of shared source if we are in share-safe mode
+
+    Config read is loaded into the ui object passed
+
+    This should be called before reading .hg/hgrc or the main repo
+    as that overrides config set in shared source"""
+    try:
+        with open(os.path.join(path, b".hg", b"requires"), "rb") as fp:
+            requirements = set(fp.read().splitlines())
+            if not (
+                requirementsmod.SHARESAFE_REQUIREMENT in requirements
+                and requirementsmod.SHARED_REQUIREMENT in requirements
+            ):
+                return
+            hgvfs = vfs.vfs(os.path.join(path, b".hg"))
+            sharedvfs = localrepo._getsharedvfs(hgvfs, requirements)
+            ui.readconfig(sharedvfs.join(b"hgrc"), path)
+    except IOError:
+        pass
+
+
 def _getlocal(ui, rpath, wd=None):
     """Return (path, local ui object) for the given target path.
 
@@ -959,12 +985,14 @@
     else:
         lui = ui.copy()
         if rcutil.use_repo_hgrc():
+            _readsharedsourceconfig(lui, path)
             lui.readconfig(os.path.join(path, b".hg", b"hgrc"), path)
 
     if rpath:
         path = lui.expandpath(rpath)
         lui = ui.copy()
         if rcutil.use_repo_hgrc():
+            _readsharedsourceconfig(lui, path)
             lui.readconfig(os.path.join(path, b".hg", b"hgrc"), path)
 
     return path, lui

--- a/tests/test-share-safe.t	Fri Sep 18 17:28:22 2020 +0530
+++ b/tests/test-share-safe.t	Fri Sep 18 18:52:38 2020 +0530
@@ -102,21 +102,14 @@
   share
   $ hg extdiff -R ../source -p echo
 
-BROKEN: the command below does not work but debugextensions says that extension
+BROKEN: the command below will not work if config of shared source is not loaded
+on dispatch but debugextensions says that extension
 is loaded
   $ hg debugextensions
   extdiff
   share
 
-BROKEN: extdiff command should work here
   $ hg extdiff -p echo
-  hg: unknown command 'extdiff'
-  'extdiff' is provided by the following extension:
-  
-      extdiff       command to allow external programs to compare revisions
-  
-  (use 'hg help extensions' for information on enabling extensions)
-  [255]
 
 However, local .hg/hgrc should override the config set by share source