diff options
authorJunio C Hamano <>2012-03-01 02:14:16 (GMT)
committerJunio C Hamano <>2012-03-01 20:00:01 (GMT)
commitb3f01ff29f7131e959bcfdfd004744d74d5fa319 (patch)
parent5597e84b514454f18bba7b13eee2feea04f0165b (diff)
diff -p: squelch "diff --git" header for stat-dirty paths
The plumbing "diff" commands look at the working tree files without refreshing the index themselves for performance reasons (the calling script is expected to do that upfront just once, before calling one or more of them). In the early days of git, they showed the "diff --git" header before they actually ask the xdiff machinery to produce patches, and ended up showing only these headers if the real contents are the same and the difference they noticed was only because the stat info cached in the index did not match that of the working tree. It was too late for the implementation to take the header that it already emitted back. But 3e97c7c (No diff -b/-w output for all-whitespace changes, 2009-11-19) introduced necessary logic to keep the meta-information headers in a strbuf and delay their output until the xdiff machinery noticed actual changes. This was primarily in order to generate patches that ignore whitespaces. When operating under "-w" mode, we wouldn't know if the header is needed until we actually look at the resulting patch, so it was a sensible thing to do, but we did not realize that the same reasoning applies to stat-dirty paths. Later, 296c6bb (diff: fix "git show -C -C" output when renaming a binary file, 2010-05-26) generalized this machinery and added must_show_header toggle. This is turned on when the header must be shown even when there is no patch to be produced, e.g. only the mode was changed, or the path was renamed, without changing the contents. However, when it did so, it still kept the special case for the "-w" mode, which meant that the plumbing would keep showing these phantom changes. This corrects this historical inconsistency by allowing the plumbing to omit paths that are only stat-dirty from its output in the same way as it handles whitespace only changes under "-w" option. The change in the behaviour can be seen in the updated test. Signed-off-by: Junio C Hamano <>
2 files changed, 2 insertions, 5 deletions
diff --git a/diff.c b/diff.c
index c8e4366..0ecbf32 100644
--- a/diff.c
+++ b/diff.c
@@ -1972,7 +1972,7 @@ static void builtin_diff(const char *name_a,
struct emit_callback ecbdata;
const struct userdiff_funcname *pe;
- if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
+ if (must_show_header) {
fprintf(o->file, "%s", header.buf);
diff --git a/t/ b/t/
index 164f153..f0d5041 100755
--- a/t/
+++ b/t/
@@ -67,10 +67,7 @@ test_expect_success SYMLINKS 'diff removed symlink and file' '
test_expect_success SYMLINKS 'diff identical, but newly created symlink and file' '
- cat >expected <<-\EOF &&
- diff --git a/frotz b/frotz
- diff --git a/nitfol b/nitfol
+ >expected &&
rm -f frotz nitfol &&
echo xyzzy >nitfol &&
test-chmtime +10 nitfol &&