log: include unmodified-in-merge files in log diff/stat (issue2383)

f02da4369319 assumed that walkchangerevs called prep with all relevant matched
filenames, but actually it only contains the names of files changed in the
relevant changeset. That meant that log diff/stat of merges missed the diff for
files only changed in the other branch.

This is a minimal fix for making sure we only use fns when we are following and
thus will have problems with merges anyway ...

mercurial/commands.py

@@ -2533,7 +2533,11 @@ def log(ui, repo, *pats, **opts):
 
         revmatchfn = None
         if opts.get('patch') or opts.get('stat'):
-            revmatchfn = cmdutil.match(repo, fns, default='path')
+            if opts.get('follow') or opts.get('follow_first'):
+                # note: this might be wrong when following through merges
+                revmatchfn = cmdutil.match(repo, fns, default='path')
+            else:
+                revmatchfn = matchfn
 
         displayer.show(ctx, copies=copies, matchfn=revmatchfn)
 

tests/test-log

@@ -194,5 +194,26 @@ echo '% log -p -R repo'
 cd dir
 hg log -p -R .. ../a
 
+cd ..
 
-exit 0
+echo '% issue2383'
+
+hg init issue2383
+cd issue2383
+echo a > a
+hg ci -Am0
+echo b > b
+hg ci -Am1
+hg co 0
+echo b > a
+hg ci -m2
+hg merge
+echo c > a
+hg ci -m3
+echo
+echo % diff
+hg diff --rev 2:3
+echo
+echo % log
+hg log -vpr 3
+cd ..

tests/test-log.out

@@ -585,3 +585,48 @@ diff -r 000000000000 -r 24427303d56f a
 @@ -0,0 +1,1 @@
 +a
 
+% issue2383
+adding a
+adding b
+0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+created new head
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+(branch merge, don't forget to commit)
+
+% diff
+diff -r b09be438c43a -r 8e07aafe1edc a
+--- a/a	Thu Jan 01 00:00:00 1970 +0000
++++ b/a	Thu Jan 01 00:00:00 1970 +0000
+@@ -1,1 +1,1 @@
+-b
++c
+diff -r b09be438c43a -r 8e07aafe1edc b
+--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
++++ b/b	Thu Jan 01 00:00:00 1970 +0000
+@@ -0,0 +1,1 @@
++b
+
+% log
+changeset:   3:8e07aafe1edc
+tag:         tip
+parent:      2:b09be438c43a
+parent:      1:925d80f479bb
+user:        test
+date:        Thu Jan 01 00:00:00 1970 +0000
+files:       a
+description:
+3
+
+
+diff -r b09be438c43a -r 8e07aafe1edc a
+--- a/a	Thu Jan 01 00:00:00 1970 +0000
++++ b/a	Thu Jan 01 00:00:00 1970 +0000
+@@ -1,1 +1,1 @@
+-b
++c
+diff -r b09be438c43a -r 8e07aafe1edc b
+--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
++++ b/b	Thu Jan 01 00:00:00 1970 +0000
+@@ -0,0 +1,1 @@
++b
+