templater: ability to display diffstat for log-like commands

mercurial/cmdutil.py

@@ -830,6 +830,15 b' class changeset_templater(changeset_prin'
                              node=hex(ctx.changeset()[0])))
             return self.t('manifest', **args)
 
+        def showdiffstat(**args):
+            diff = patch.diff(self.repo, ctx.parents()[0].node(), ctx.node())
+            files, adds, removes = 0, 0, 0
+            for i in patch.diffstatdata(util.iterlines(diff)):
+                files += 1
+                adds += i[1]
+                removes += i[2]
+            return '%s: +%s/-%s' % (files, adds, removes)
+
         defprops = {
             'author': ctx.user(),
             'branches': showbranches,
@@ -846,6 +855,7 b' class changeset_templater(changeset_prin'
             'rev': ctx.rev(),
             'tags': showtags,
             'extras': showextras,
+            'diffstat': showdiffstat,
             }
         props = props.copy()
         props.update(defprops)

mercurial/help.py

@@ -286,6 +286,8 b' PYTHONPATH::'
           was committed. Will be empty if the branch name was default.
     - date: Date information. The date when the changeset was committed.
     - desc: String. The text of the changeset description.
+    - diffstat: String. Statistics of changes with the following format:
+          "modified files: +added/-removed lines"
     - files: List of strings. All files modified, added, or removed by
           this changeset.
     - file_adds: List of strings. Files added by this changeset.

mercurial/util.py

@@ -2017,3 +2017,8 b' def termwidth():'
     except ImportError:
         pass
     return 80
+
+def iterlines(iterator):
+    for chunk in iterator:
+        for line in chunk.splitlines():
+            yield line

tests/test-command-template

@@ -93,7 +93,7 b' cat changelog'
 
 echo "# keys work"
 for key in author branches date desc file_adds file_dels file_mods \
-        files manifest node parents rev tags; do
+        files manifest node parents rev tags diffstat; do
     for mode in '' --verbose --debug; do
         hg log $mode --template "$key$mode: {$key}\n"
     done

tests/test-command-template.out

@@ -534,6 +534,33 b' tags--debug:'
 tags--debug: 
 tags--debug: 
 tags--debug: 
+diffstat: 1: +1/-0
+diffstat: 1: +1/-0
+diffstat: 0: +0/-0
+diffstat: 1: +1/-0
+diffstat: 0: +0/-0
+diffstat: 1: +1/-0
+diffstat: 1: +4/-0
+diffstat: 1: +2/-0
+diffstat: 1: +1/-0
+diffstat--verbose: 1: +1/-0
+diffstat--verbose: 1: +1/-0
+diffstat--verbose: 0: +0/-0
+diffstat--verbose: 1: +1/-0
+diffstat--verbose: 0: +0/-0
+diffstat--verbose: 1: +1/-0
+diffstat--verbose: 1: +4/-0
+diffstat--verbose: 1: +2/-0
+diffstat--verbose: 1: +1/-0
+diffstat--debug: 1: +1/-0
+diffstat--debug: 1: +1/-0
+diffstat--debug: 0: +0/-0
+diffstat--debug: 1: +1/-0
+diffstat--debug: 0: +0/-0
+diffstat--debug: 1: +1/-0
+diffstat--debug: 1: +4/-0
+diffstat--debug: 1: +2/-0
+diffstat--debug: 1: +1/-0
 # filters work
 
 hostname