[PATCH 2 of 4] hg: add --binary option for Git mode diffs

[Alexander Fomin]

# HG changeset patch
# User Alexander Fomin <afomin at fb.com>
# Date 1491334100 25200
#      Tue Apr 04 12:28:20 2017 -0700
# Node ID 27515c7e38db9d93e18b7df13149da7c0d88eeb2
# Parent  9be2b4ec19e846d2a95fe801ebe76f83fffd1ea9
hg: add --binary option for Git mode diffs

This patch adds --binary option to `hg diff` and `hg export` to allow more
control about when binary diffs are displayed in Git mode (issue5510).

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -160,6 +160,7 @@ logopts = [
 diffopts = [
     ('a', 'text', None, _('treat all files as text')),
     ('g', 'git', None, _('use git extended diff format')),
+    ('', 'binary', None, _('generate binary diffs in Git mode (default)')),
     ('', 'nodates', None, _('omit dates from diff headers'))
 ]
 
diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -2210,7 +2210,9 @@ def difffeatureopts(ui, opts=None, untru
                                             'ignoreblanklines')
     if formatchanging:
         buildopts['text'] = opts and opts.get('text')
-        buildopts['nobinary'] = get('nobinary', forceplain=False)
+        binary = None if opts is None else opts.get('binary')
+        buildopts['nobinary'] = (not binary if binary is not None
+                                 else get('nobinary', forceplain=False))
         buildopts['noprefix'] = get('noprefix', forceplain=False)
 
     return mdiff.diffopts(**buildopts)
diff --git a/tests/test-completion.t b/tests/test-completion.t
--- a/tests/test-completion.t
+++ b/tests/test-completion.t
@@ -216,8 +216,8 @@ Show all commands + options
   annotate: rev, follow, no-follow, text, user, file, date, number, changeset, line-number, ignore-all-space, ignore-space-change, ignore-blank-lines, include, exclude, template
   clone: noupdate, updaterev, rev, branch, pull, uncompressed, ssh, remotecmd, insecure
   commit: addremove, close-branch, amend, secret, edit, interactive, include, exclude, message, logfile, date, user, subrepos
-  diff: rev, change, text, git, nodates, noprefix, show-function, reverse, ignore-all-space, ignore-space-change, ignore-blank-lines, unified, stat, root, include, exclude, subrepos
-  export: output, switch-parent, rev, text, git, nodates
+  diff: rev, change, text, git, binary, nodates, noprefix, show-function, reverse, ignore-all-space, ignore-space-change, ignore-blank-lines, unified, stat, root, include, exclude, subrepos
+  export: output, switch-parent, rev, text, git, binary, nodates
   forget: include, exclude
   init: ssh, remotecmd, insecure
   log: follow, follow-first, date, copies, keyword, rev, removed, only-merges, user, only-branch, branch, prune, patch, git, limit, no-merges, stat, graph, style, template, include, exclude
diff --git a/tests/test-help.t b/tests/test-help.t
--- a/tests/test-help.t
+++ b/tests/test-help.t
@@ -543,6 +543,7 @@ Test command without options
    -c --change REV          change made by revision
    -a --text                treat all files as text
    -g --git                 use git extended diff format
+      --binary              generate binary diffs in Git mode (default)
       --nodates             omit dates from diff headers
       --noprefix            omit a/ and b/ prefixes from filenames
    -p --show-function       show which function each change is in