merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/t/t3411-rebase-preserve-around-merges.sh

@@ -0,0 +1,80 @@
+#!/bin/sh
+#
+# Copyright (c) 2008 Stephen Haberman
+#
+
+test_description='git rebase preserve merges
+
+This test runs git rebase with -p and tries to squash a commit from after
+a merge to before the merge.
+'
+. ./test-lib.sh
+
+if ! test_have_prereq REBASE_P; then
+	skip_all='skipping git rebase -p tests, as asked for'
+	test_done
+fi
+
+. "$TEST_DIRECTORY"/lib-rebase.sh
+
+set_fake_editor
+
+# set up two branches like this:
+#
+# A1 - B1 - D1 - E1 - F1
+#       \        /
+#        -- C1 --
+
+test_expect_success 'setup' '
+	test_commit A1 &&
+	test_commit B1 &&
+	test_commit C1 &&
+	git reset --hard B1 &&
+	test_commit D1 &&
+	test_merge E1 C1 &&
+	test_commit F1
+'
+
+# Should result in:
+#
+# A1 - B1 - D2 - E2
+#       \        /
+#        -- C1 --
+#
+test_expect_success 'squash F1 into D1' '
+	FAKE_LINES="1 squash 4 2 3" git rebase -i -p B1 &&
+	test "$(git rev-parse HEAD^2)" = "$(git rev-parse C1)" &&
+	test "$(git rev-parse HEAD~2)" = "$(git rev-parse B1)" &&
+	git tag E2
+'
+
+# Start with:
+#
+# A1 - B1 - D2 - E2
+#  \
+#   G1 ---- L1 ---- M1
+#    \             /
+#     H1 -- J1 -- K1
+#      \         /
+#        -- I1 --
+#
+# And rebase G1..M1 onto E2
+
+test_expect_success 'rebase two levels of merge' '
+	git checkout A1 &&
+	test_commit G1 &&
+	test_commit H1 &&
+	test_commit I1 &&
+	git checkout -b branch3 H1 &&
+	test_commit J1 &&
+	test_merge K1 I1 &&
+	git checkout -b branch2 G1 &&
+	test_commit L1 &&
+	test_merge M1 K1 &&
+	GIT_EDITOR=: git rebase -i -p E2 &&
+	test "$(git rev-parse HEAD~3)" = "$(git rev-parse E2)" &&
+	test "$(git rev-parse HEAD~2)" = "$(git rev-parse HEAD^2^2~2)" &&
+	test "$(git rev-parse HEAD^2^1^1)" = "$(git rev-parse HEAD^2^2^1)"
+'
+
+test_done