Merge branch 'al/bisect-first-parent'

"git bisect" learns the "--first-parent" option to find the first
breakage along the first-parent chain.

* al/bisect-first-parent:
  bisect: combine args passed to find_bisection()
  bisect: introduce first-parent flag
  cmd_bisect__helper: defer parsing no-checkout flag
  rev-list: allow bisect and first-parent flags
  t6030: modernize "git bisect run" tests

3 files changed, 103 insertions, 50 deletions

diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 3bb0e4ff8f..fc4d55dcb2 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -128,8 +128,8 @@ test_expect_success 'rev-list can negate index objects' '
 	test_cmp expect actual
 '
 
-test_expect_success '--bisect and --first-parent can not be combined' '
-	test_must_fail git rev-list --bisect --first-parent HEAD
+test_expect_success '--bisect and --first-parent can be combined' '
+	git rev-list --bisect --first-parent HEAD
 '
 
 test_expect_success '--header shows a NUL after each commit' '
diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh
index a661408038..b95a0212ad 100755
--- a/t/t6002-rev-list-bisect.sh
+++ b/t/t6002-rev-list-bisect.sh
@@ -263,4 +263,49 @@ test_expect_success 'rev-parse --bisect can default to good/bad refs' '
 	test_cmp expect.sorted actual.sorted
 '
 
+test_output_expect_success '--bisect --first-parent' 'git rev-list --bisect --first-parent E ^F' <<EOF
+e4
+EOF
+
+test_output_expect_success '--first-parent' 'git rev-list --first-parent E ^F' <<EOF
+E
+e1
+e2
+e3
+e4
+e5
+e6
+e7
+e8
+EOF
+
+test_output_expect_success '--bisect-vars --first-parent' 'git rev-list --bisect-vars --first-parent E ^F' <<EOF
+bisect_rev='e5'
+bisect_nr=4
+bisect_good=4
+bisect_bad=3
+bisect_all=9
+bisect_steps=2
+EOF
+
+test_expect_success '--bisect-all --first-parent' '
+	cat >expect.unsorted <<-EOF &&
+	$(git rev-parse E) (tag: E, dist=0)
+	$(git rev-parse e1) (tag: e1, dist=1)
+	$(git rev-parse e2) (tag: e2, dist=2)
+	$(git rev-parse e3) (tag: e3, dist=3)
+	$(git rev-parse e4) (tag: e4, dist=4)
+	$(git rev-parse e5) (tag: e5, dist=4)
+	$(git rev-parse e6) (tag: e6, dist=3)
+	$(git rev-parse e7) (tag: e7, dist=2)
+	$(git rev-parse e8) (tag: e8, dist=1)
+	EOF
+
+	# expect results to be ordered by distance (descending),
+	# commit hash (ascending)
+	sort -k4,4r -k1,1 expect.unsorted >expect &&
+	git rev-list --bisect-all --first-parent E ^F >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 36d9b2b2e4..b886529e59 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -243,32 +243,30 @@ test_expect_success 'bisect skip: with commit both bad and skipped' '
 '
 
 # We want to automatically find the commit that
-# introduced "Another" into hello.
-test_expect_success \
-    '"git bisect run" simple case' \
-    'echo "#"\!"/bin/sh" > test_script.sh &&
-     echo "grep Another hello > /dev/null" >> test_script.sh &&
-     echo "test \$? -ne 0" >> test_script.sh &&
-     chmod +x test_script.sh &&
-     git bisect start &&
-     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 &&
-     git bisect reset'
+# added "Another" into hello.
+test_expect_success '"git bisect run" simple case' '
+	write_script test_script.sh <<-\EOF &&
+	! grep Another hello >/dev/null
+	EOF
+	git bisect start &&
+	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 &&
+	git bisect reset
+'
 
 # We want to automatically find the commit that
-# introduced "Ciao" into hello.
-test_expect_success \
-    '"git bisect run" with more complex "git bisect start"' \
-    'echo "#"\!"/bin/sh" > test_script.sh &&
-     echo "grep Ciao hello > /dev/null" >> test_script.sh &&
-     echo "test \$? -ne 0" >> test_script.sh &&
-     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 &&
-     git bisect reset'
+# added "Ciao" into hello.
+test_expect_success '"git bisect run" with more complex "git bisect start"' '
+	write_script test_script.sh <<-\EOF &&
+	! grep Ciao hello >/dev/null
+	EOF
+	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 &&
+	git bisect reset
+'
 
 # $HASH1 is good, $HASH5 is bad, we skip $HASH3
 # but $HASH4 is good,
@@ -295,24 +293,17 @@ HASH6=
 test_expect_success 'bisect run & skip: cannot tell between 2' '
 	add_line_into_file "6: Yet a line." hello &&
 	HASH6=$(git rev-parse --verify HEAD) &&
-	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "grep line hello > /dev/null" >> test_script.sh &&
-	echo "test \$? -ne 0" >> test_script.sh &&
-	chmod +x test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	sed -ne \$p hello | grep Ciao >/dev/null && exit 125
+	! grep line hello >/dev/null
+	EOF
 	git bisect start $HASH6 $HASH1 &&
-	if git bisect run ./test_script.sh > my_bisect_log.txt
-	then
-		echo Oops, should have failed.
-		false
-	else
-		test $? -eq 2 &&
-		grep "first bad commit could be any of" my_bisect_log.txt &&
-		! grep $HASH3 my_bisect_log.txt &&
-		! grep $HASH6 my_bisect_log.txt &&
-		grep $HASH4 my_bisect_log.txt &&
-		grep $HASH5 my_bisect_log.txt
-	fi
+	test_expect_code 2 git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "first bad commit could be any of" my_bisect_log.txt &&
+	! grep $HASH3 my_bisect_log.txt &&
+	! grep $HASH6 my_bisect_log.txt &&
+	grep $HASH4 my_bisect_log.txt &&
+	grep $HASH5 my_bisect_log.txt
 '
 
 HASH7=
@@ -320,14 +311,13 @@ test_expect_success 'bisect run & skip: find first bad' '
 	git bisect reset &&
 	add_line_into_file "7: Should be the last line." hello &&
 	HASH7=$(git rev-parse --verify HEAD) &&
-	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "sed -ne \\\$p hello | grep day > /dev/null && exit 125" >> test_script.sh &&
-	echo "grep Yet hello > /dev/null" >> test_script.sh &&
-	echo "test \$? -ne 0" >> test_script.sh &&
-	chmod +x test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	sed -ne \$p hello | grep Ciao >/dev/null && exit 125
+	sed -ne \$p hello | grep day >/dev/null && exit 125
+	! grep Yet hello >/dev/null
+	EOF
 	git bisect start $HASH7 $HASH1 &&
-	git bisect run ./test_script.sh > my_bisect_log.txt &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
 	grep "$HASH6 is the first bad commit" my_bisect_log.txt
 '
 
@@ -458,6 +448,24 @@ test_expect_success 'many merge bases creation' '
 	grep "$SIDE_HASH5" merge_bases.txt
 '
 
+# We want to automatically find the merge that
+# added "line" into hello.
+test_expect_success '"git bisect run --first-parent" simple case' '
+	git rev-list --first-parent $B_HASH ^$HASH4 >first_parent_chain.txt &&
+	write_script test_script.sh <<-\EOF &&
+	grep $(git rev-parse HEAD) first_parent_chain.txt || exit -1
+	! grep line hello >/dev/null
+	EOF
+	git bisect start --first-parent &&
+	test_path_is_file ".git/BISECT_FIRST_PARENT" &&
+	git bisect good $HASH4 &&
+	git bisect bad $B_HASH &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$B_HASH is the first bad commit" my_bisect_log.txt &&
+	git bisect reset &&
+	test_path_is_missing .git/BISECT_FIRST_PARENT
+'
+
 test_expect_success 'good merge bases when good and bad are siblings' '
 	git bisect start "$B_HASH" "$A_HASH" > my_bisect_log.txt &&
 	test_i18ngrep "merge base must be tested" my_bisect_log.txt &&