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)

-

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)

-

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

-

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.
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' >cu...
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