subrepo: add argument to "diff()" to pass "ui" of caller side (issue3712) (API)

Color extension achieves colorization by overriding the class of
"ui" object just before command execution.

Before this patch, "diff()" of abstractsubrepo and classes
derived from it has no "ui" argument, so "diff()" of hgsubrepo
uses "self._repo.ui" to invoke "cmdutil.diffordiffstat()".

For separation of configuration between repositories, revision
573bec4ab7ba changed the initialization source of "self._repo.ui"
from "ui"(overridden) to "baseui"(plain) of parent repository.
And this caused break of colorization.

This patch adds "ui" argument to "diff()" of abstractsubrepo and
classes derived from it to pass "ui" object of caller side.

mercurial/cmdutil.py

@@ -627,7 +627,7 b' def diffordiffstat(ui, repo, diffopts, n'
                 # subpath. The best we can do is to ignore it.
                 tempnode2 = None
             submatch = matchmod.narrowmatcher(subpath, match)
-            sub.diff(diffopts, tempnode2, submatch, changes=changes,
+            sub.diff(ui, diffopts, tempnode2, submatch, changes=changes,
                      stat=stat, fp=fp, prefix=prefix)
 
 class changeset_printer(object):

mercurial/subrepo.py

@@ -330,7 +330,7 b' class abstractsubrepo(object):'
     def status(self, rev2, **opts):
         return [], [], [], [], [], [], []
 
-    def diff(self, diffopts, node2, match, prefix, **opts):
+    def diff(self, ui, diffopts, node2, match, prefix, **opts):
         pass
 
     def outgoing(self, ui, dest, opts):
@@ -437,14 +437,14 b' class hgsubrepo(abstractsubrepo):'
                                % (inst, subrelpath(self)))
             return [], [], [], [], [], [], []
 
-    def diff(self, diffopts, node2, match, prefix, **opts):
+    def diff(self, ui, diffopts, node2, match, prefix, **opts):
         try:
             node1 = node.bin(self._state[1])
             # We currently expect node2 to come from substate and be
             # in hex format
             if node2 is not None:
                 node2 = node.bin(node2)
-            cmdutil.diffordiffstat(self._repo.ui, self._repo, diffopts,
+            cmdutil.diffordiffstat(ui, self._repo, diffopts,
                                    node1, node2, match,
                                    prefix=os.path.join(prefix, self._path),
                                    listsubrepos=True, **opts)

tests/test-diff-color.t

@@ -125,6 +125,38 b' qrecord'
    c
   \x1b[0;33mrecord this change to 'a'? [Ynesfdaq?]\x1b[0m  (esc)
 
+  $ hg qpop -a
+  popping patch
+  patch queue now empty
+
 #endif
 
+issue3712: test colorization of subrepo diff
+
+  $ hg init sub
+  $ echo b > sub/b
+  $ hg -R sub commit -Am 'create sub'
+  adding b
+  $ echo 'sub = sub' > .hgsub
+  $ hg add .hgsub
+  $ hg commit -m 'add subrepo sub'
+  $ echo aa >> a
+  $ echo bb >> sub/b
+
+  $ hg diff --color=always -S
+  \x1b[0;1mdiff --git a/a b/a\x1b[0m (esc)
+  \x1b[0;31;1m--- a/a\x1b[0m (esc)
+  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
+  \x1b[0;35m@@ -7,3 +7,4 @@\x1b[0m (esc)
+   a
+   c
+   c
+  \x1b[0;32m+aa\x1b[0m (esc)
+  \x1b[0;1mdiff --git a/sub/b b/sub/b\x1b[0m (esc)
+  \x1b[0;31;1m--- a/sub/b\x1b[0m (esc)
+  \x1b[0;32;1m+++ b/sub/b\x1b[0m (esc)
+  \x1b[0;35m@@ -1,1 +1,2 @@\x1b[0m (esc)
+   b
+  \x1b[0;32m+bb\x1b[0m (esc)
+
   $ cd ..