[PATCH v2] bisect: improve output when bad commit is found

[Trevor Saunders <tbsaunde@tbsaunde.org>]

When the first bad commit has been found git bisect prints something
like this:

	<40 char sha1> is the first bad commit
	Commit <40 char sha1>
	...

	:100644 100644 10f5e57... a46cfeb... M  bisect.c
	:100755 100755 ae3fec2... 65a19fa... M  git-bisect.sh

The raw diff output is not really useful, and its kind of silly to print
the sha1 twice.  Instead lets print something like this:

	The first bad commit is
	Commit <sha1>
	...

This also fixes an odd inconsistancy where if the first bad commit is a
trivial merge git bisect will only print the first line.

Signed-off-by: Trevor Saunders <tbsaunde@tbsaunde.org>
---
 bisect.c                    |  9 +++------
 git-bisect.sh               |  2 +-
 t/t6030-bisect-porcelain.sh | 36 +++++++++++++++++++++++++-----------
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/bisect.c b/bisect.c
index 10f5e57..a46cfeb 100644
--- a/bisect.c
+++ b/bisect.c
@@ -875,17 +875,14 @@ static void show_diff_tree(const char *prefix, struct commit *commit)
 	init_revisions(&opt, prefix);
 	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	opt.abbrev = 0;
-	opt.diff = 1;
+	opt.diff = 0;
+	opt.always_show_header = 1;
 
 	/* This is what "--pretty" does */
 	opt.verbose_header = 1;
 	opt.use_terminator = 0;
 	opt.commit_format = CMIT_FMT_DEFAULT;
 
-	/* diff-tree init */
-	if (!opt.diffopt.output_format)
-		opt.diffopt.output_format = DIFF_FORMAT_RAW;
-
 	log_tree_commit(&opt, commit);
 }
 
@@ -942,7 +939,7 @@ int bisect_next_all(const char *prefix, int no_checkout)
 
 	if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
 		exit_if_skipped_commits(tried, current_bad_oid);
-		printf("%s is the first bad commit\n", bisect_rev_hex);
+		puts("The first bad commit is");
 		show_diff_tree(prefix, revs.commits->item);
 		/* This means the bisection process succeeded. */
 		exit(10);
diff --git a/git-bisect.sh b/git-bisect.sh
index ae3fec2..65a19fa 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -480,7 +480,7 @@ exit code \$res from '\$command' is < 0 or >= 128" >&2
 			exit $res
 		fi
 
-		if sane_grep "is the first bad commit" "$GIT_DIR/BISECT_RUN" >/dev/null
+		if sane_grep "The first bad commit is" "$GIT_DIR/BISECT_RUN" >/dev/null
 		then
 			gettextln "bisect run success"
 			exit 0;
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 06b4868..43f420d 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -26,6 +26,20 @@ add_line_into_file()
     git commit --quiet -m "$MSG" $_file
 }
 
+check_bisect_msg () {
+	file=$1
+	hash=$2
+	echo "The first bad commit is" > expect &&
+	git show -s --no-abbrev $hash >> expect &&
+	if test -n "$3"
+       	then
+		echo $3 >> expect || return $?
+	fi
+	cnt=$(wc -l <expect) &&
+	tail -n $cnt "$file" > actual &&
+	test_cmp expect actual
+}
+
 HASH1=
 HASH2=
 HASH3=
@@ -189,7 +203,7 @@ test_expect_success 'bisect skip: successful result' '
 	git bisect start $HASH4 $HASH1 &&
 	git bisect skip &&
 	git bisect bad > my_bisect_log.txt &&
-	grep "$HASH2 is the first bad commit" my_bisect_log.txt
+	check_bisect_msg my_bisect_log.txt $HASH2
 '
 
 # $HASH1 is good, $HASH4 is bad, we skip $HASH3 and $HASH2
@@ -254,7 +268,7 @@ test_expect_success \
      git bisect good $HASH1 &&
      git bisect bad $HASH4 &&
      git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH3 is the first bad commit" my_bisect_log.txt &&
+     check_bisect_msg my_bisect_log.txt $HASH3 "bisect run success" &&
      git bisect reset'
 
 # We want to automatically find the commit that
@@ -267,7 +281,7 @@ test_expect_success \
      chmod +x test_script.sh &&
      git bisect start $HASH4 $HASH1 &&
      git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH4 is the first bad commit" my_bisect_log.txt &&
+     check_bisect_msg my_bisect_log.txt $HASH4 "bisect run success" &&
      git bisect reset'
 
 # $HASH1 is good, $HASH5 is bad, we skip $HASH3
@@ -280,14 +294,14 @@ test_expect_success 'bisect skip: add line and then a new test' '
 	git bisect start $HASH5 $HASH1 &&
 	git bisect skip &&
 	git bisect good > my_bisect_log.txt &&
-	grep "$HASH5 is the first bad commit" my_bisect_log.txt &&
+	check_bisect_msg my_bisect_log.txt $HASH5 &&
 	git bisect log > log_to_replay.txt &&
 	git bisect reset
 '
 
 test_expect_success 'bisect skip and bisect replay' '
 	git bisect replay log_to_replay.txt > my_bisect_log.txt &&
-	grep "$HASH5 is the first bad commit" my_bisect_log.txt &&
+	check_bisect_msg my_bisect_log.txt $HASH5 &&
 	git bisect reset
 '
 
@@ -328,7 +342,7 @@ test_expect_success 'bisect run & skip: find first bad' '
 	chmod +x test_script.sh &&
 	git bisect start $HASH7 $HASH1 &&
 	git bisect run ./test_script.sh > my_bisect_log.txt &&
-	grep "$HASH6 is the first bad commit" my_bisect_log.txt
+	check_bisect_msg my_bisect_log.txt $HASH6 "bisect run success"
 '
 
 test_expect_success 'bisect skip only one range' '
@@ -378,7 +392,7 @@ test_expect_success 'bisect does not create a "bisect" branch' '
 	rev_hash6=$(git rev-parse --verify HEAD) &&
 	test "$rev_hash6" = "$HASH6" &&
 	git bisect good > my_bisect_log.txt &&
-	grep "$HASH7 is the first bad commit" my_bisect_log.txt &&
+	check_bisect_msg my_bisect_log.txt $HASH7 &&
 	git bisect reset &&
 	rev_hash6=$(git rev-parse --verify bisect) &&
 	test "$rev_hash6" = "$HASH6" &&
@@ -527,7 +541,7 @@ test_expect_success 'restricting bisection on one dir' '
 	para1=$(git rev-parse --verify HEAD) &&
 	test "$para1" = "$PARA_HASH1" &&
 	git bisect bad > my_bisect_log.txt &&
-	grep "$PARA_HASH1 is the first bad commit" my_bisect_log.txt
+	check_bisect_msg my_bisect_log.txt $PARA_HASH1
 '
 
 test_expect_success 'restricting bisection on one dir and a file' '
@@ -545,7 +559,7 @@ test_expect_success 'restricting bisection on one dir and a file' '
 	para1=$(git rev-parse --verify HEAD) &&
 	test "$para1" = "$PARA_HASH1" &&
 	git bisect good > my_bisect_log.txt &&
-	grep "$PARA_HASH4 is the first bad commit" my_bisect_log.txt
+	check_bisect_msg my_bisect_log.txt $PARA_HASH4
 '
 
 test_expect_success 'skipping away from skipped commit' '
@@ -576,7 +590,7 @@ test_expect_success 'test bisection on bare repo - --no-checkout specified' '
 			"test \$(git rev-list BISECT_HEAD ^$HASH2 --max-count=1 | wc -l) = 0" \
 			>../nocheckout.log
 	) &&
-	grep "$HASH3 is the first bad commit" nocheckout.log
+	check_bisect_msg  nocheckout.log $HASH3 "bisect run success"
 '
 
 
@@ -591,7 +605,7 @@ test_expect_success 'test bisection on bare repo - --no-checkout defaulted' '
 			"test \$(git rev-list BISECT_HEAD ^$HASH2 --max-count=1 | wc -l) = 0" \
 			>../defaulted.log
 	) &&
-	grep "$HASH3 is the first bad commit" defaulted.log
+	check_bisect_msg defaulted.log $HASH3 "bisect run success"
 '
 
 #
-- 
2.4.0.78.g7c6ecbf