threads / bug / 10193

Fix embarrassing "git log --follow" bug

Subject: Fix embarrassing "git log --follow" bug

## tl;dr

4 messages between Oct 8, 2007 and Oct 9, 2007.

replies: 3people: 1as markdown or json

Linus Torvalds· Oct 8, 2007, 20:42 UTC · lore

It turns out that I completely broke "git log --follow" with my recent patch to revision.c ("Fix revision log diff setup, avoid unnecessary diff generation", commit b7bb760d5ed4881422673d32f869d140221d3564).

Why? Because --follow obviously requires the diff machinery to function, exactly the same way pickaxe does.

So everybody is away right now, but considering that nobody even noticed this bug, I don't think it matters. But for the record, here's the trivial one-liner fix (well, two, since I also fixed the comment).

Because of the nature of the bug, if you ask for patches when following (which is one of the things I normally do), the bug is hidden, because then the request for diff output will automatically also enable the diffs themselves.

So while "git log --follow <filename>" didn't work, adding a "-p" magically made it work again even without this fix.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 revision.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/revision.c b/revision.c
index 5d294be..e76da0d 100644
--- a/revision.c
+++ b/revision.c
@@ -1241,8 +1241,8 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 	if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
 		revs->diff = 1;
 
-	/* Pickaxe needs diffs */
-	if (revs->diffopt.pickaxe)
+	/* Pickaxe and rename following needs diffs */
+	if (revs->diffopt.pickaxe || revs->diffopt.follow_renames)
 		revs->diff = 1;
 
 	if (revs->topo_order)

Linus Torvalds· Oct 8, 2007, 20:46 UTC · re: Linus Torvalds · lore

Clean up "git log" format with DIFF_FORMAT_NO_OUTPUT

This fixes an unnecessary empty line that we add to the log message when we generate diffs, but don't actually end up printing any due to having DIFF_FORMAT_NO_OUTPUT set.

This can happen with pickaxe or with rename following. The reason is that we normally add an empty line between the commit and the diff, but we do that even for the case where we've then suppressed the actual printing of the diff.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 log-tree.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/log-tree.c b/log-tree.c
index 2319154..62edd34 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -304,7 +304,8 @@ int log_tree_diff_flush(struct rev_info *opt)
 		 * output for readability.
 		 */
 		show_log(opt, opt->diffopt.msg_sep);
-		if (opt->verbose_header &&
+		if ((opt->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT) &&
+		    opt->verbose_header &&
 		    opt->commit_format != CMIT_FMT_ONELINE) {
 			int pch = DIFF_FORMAT_DIFFSTAT | DIFF_FORMAT_PATCH;
 			if ((pch & opt->diffopt.output_format) == pch)

Linus Torvalds· Oct 8, 2007, 20:55 UTC · re: Linus Torvalds · lore

Re: Clean up "git log" format with DIFF_FORMAT_NO_OUTPUT

On Mon, 8 Oct 2007, Linus Torvalds wrote:

> 
> This fixes an unnecessary empty line that we add to the log message when 
> we generate diffs, but don't actually end up printing any due to having 
> DIFF_FORMAT_NO_OUTPUT set.

Btw, this seems to break a few tests, where the test assumed the extra newlines at the end of commands like "git show -s" (which also triggered the extra unnecessary padding between commit text and the suppressed diff).

I think the patch is correct, but the tests obviously would need fixing before this patch should be applied.

		Linus

Linus Torvalds· Oct 9, 2007, 16:35 UTC · re: Linus Torvalds · lore

[take 2] Clean up "git log" format with DIFF_FORMAT_NO_OUTPUT

Clean up "git log" format with DIFF_FORMAT_NO_OUTPUT

This fixes an unnecessary empty line that we add to the log message when we generate diffs, but don't actually end up printing any due to having DIFF_FORMAT_NO_OUTPUT set.

This also updates a couple of tests that assumed the extraneous empty line would exist at the end of output.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

This is a resend of the original patch, with just the changes to the tests added to make it pass them all. Both of the tests actually got cleaner, I think (ie one had the sed script blindly just delete the last line in order to match it up with the known input, for example).

			Linus

 log-tree.c                  |    3 ++-
 t/t3900-i18n-commit.sh      |    2 +-
 t/t4013/diff.log_-SF_master |    1 -
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/log-tree.c b/log-tree.c
index 2319154..62edd34 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -304,7 +304,8 @@ int log_tree_diff_flush(struct rev_info *opt)
 		 * output for readability.
 		 */
 		show_log(opt, opt->diffopt.msg_sep);
-		if (opt->verbose_header &&
+		if ((opt->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT) &&
+		    opt->verbose_header &&
 		    opt->commit_format != CMIT_FMT_ONELINE) {
 			int pch = DIFF_FORMAT_DIFFSTAT | DIFF_FORMAT_PATCH;
 			if ((pch & opt->diffopt.output_format) == pch)
diff --git a/t/t3900-i18n-commit.sh b/t/t3900-i18n-commit.sh
index fcbabe8..94b1c24 100755
--- a/t/t3900-i18n-commit.sh
+++ b/t/t3900-i18n-commit.sh
@@ -8,7 +8,7 @@ test_description='commit and log output encodings'
 . ./test-lib.sh
 
 compare_with () {
-	git show -s $1 | sed -e '1,/^$/d' -e 's/^    //' -e '$d' >current &&
+	git show -s $1 | sed -e '1,/^$/d' -e 's/^    //' >current &&
 	git diff current "$2"
 }
 
diff --git a/t/t4013/diff.log_-SF_master b/t/t4013/diff.log_-SF_master
index 6162ed2..c1599f2 100644
--- a/t/t4013/diff.log_-SF_master
+++ b/t/t4013/diff.log_-SF_master
@@ -4,5 +4,4 @@ Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:02:00 2006 +0000
 
     Third
-
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