Merge branch 'mk/blame-first-parent'

"git blame" learnt to take "--first-parent" and "--reverse" at the
same time when it makes sense.

* mk/blame-first-parent:
  blame: allow blame --reverse --first-parent when it makes sense
  blame: extract find_single_final
  blame: test to describe use of blame --reverse --first-parent

1 files changed, 36 insertions, 0 deletions

diff --git a/t/t8009-blame-vs-topicbranches.sh b/t/t8009-blame-vs-topicbranches.sh
new file mode 100755
index 0000000000..72596e38b2
--- /dev/null
+++ b/t/t8009-blame-vs-topicbranches.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description='blaming trough history with topic branches'
+. ./test-lib.sh
+
+# Creates the history shown below. '*'s mark the first parent in the merges.
+# The only line of file.t is changed in commit B2
+#
+#        +---C1
+#       /      \
+# A0--A1--*A2--*A3
+#   \     /
+#    B1-B2
+#
+test_expect_success setup '
+	test_commit A0 file.t line0 &&
+	test_commit A1 &&
+	git reset --hard A0 &&
+	test_commit B1 &&
+	test_commit B2 file.t line0changed &&
+	git reset --hard A1 &&
+	test_merge A2 B2 &&
+	git reset --hard A1 &&
+	test_commit C1 &&
+	git reset --hard A2 &&
+	test_merge A3 C1
+	'
+
+test_expect_success 'blame --reverse --first-parent finds A1' '
+	git blame --porcelain --reverse --first-parent A0..A3 -- file.t >actual_full &&
+	head -n 1 <actual_full | sed -e "s/ .*//" >actual &&
+	git rev-parse A1 >expect &&
+	test_cmp expect actual
+	'
+
+test_done