1 files changed, 308 insertions, 0 deletions
diff --git a/t/t6010-merge-base.sh b/t/t6010-merge-base.sh
new file mode 100755
index 000000000000..44c726ea397c
--- /dev/null
+++ b/t/t6010-merge-base.sh
@@ -0,0 +1,308 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Junio C Hamano
+#
+
+test_description='Merge base and parent list computation.
+'
+
+. ./test-lib.sh
+
+M=1130000000
+Z=+0000
+
+GIT_COMMITTER_EMAIL=git@comm.iter.xz
+GIT_COMMITTER_NAME='C O Mmiter'
+GIT_AUTHOR_NAME='A U Thor'
+GIT_AUTHOR_EMAIL=git@au.thor.xz
+export GIT_COMMITTER_EMAIL GIT_COMMITTER_NAME GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL
+
+doit () {
+	OFFSET=$1 &&
+	NAME=$2 &&
+	shift 2 &&
+
+	PARENTS= &&
+	for P
+	do
+		PARENTS="${PARENTS}-p $P "
+	done &&
+
+	GIT_COMMITTER_DATE="$(($M + $OFFSET)) $Z" &&
+	GIT_AUTHOR_DATE=$GIT_COMMITTER_DATE &&
+	export GIT_COMMITTER_DATE GIT_AUTHOR_DATE &&
+
+	commit=$(echo $NAME | git commit-tree $T $PARENTS) &&
+
+	git update-ref "refs/tags/$NAME" "$commit" &&
+	echo $commit
+}
+
+test_expect_success 'setup' '
+	T=$(git mktree </dev/null)
+'
+
+test_expect_success 'set up G and H' '
+	# E---D---C---B---A
+	# \"-_         \   \
+	#  \  `---------G   \
+	#   \                \
+	#    F----------------H
+	E=$(doit 5 E) &&
+	D=$(doit 4 D $E) &&
+	F=$(doit 6 F $E) &&
+	C=$(doit 3 C $D) &&
+	B=$(doit 2 B $C) &&
+	A=$(doit 1 A $B) &&
+	G=$(doit 7 G $B $E) &&
+	H=$(doit 8 H $A $F)
+'
+
+test_expect_success 'merge-base G H' '
+	git name-rev $B >expected &&
+
+	MB=$(git merge-base G H) &&
+	git name-rev "$MB" >actual.single &&
+
+	MB=$(git merge-base --all G H) &&
+	git name-rev "$MB" >actual.all &&
+
+	MB=$(git show-branch --merge-base G H) &&
+	git name-rev "$MB" >actual.sb &&
+
+	test_cmp expected actual.single &&
+	test_cmp expected actual.all &&
+	test_cmp expected actual.sb
+'
+
+test_expect_success 'merge-base/show-branch --independent' '
+	git name-rev "$H" >expected1 &&
+	git name-rev "$H" "$G" >expected2 &&
+
+	parents=$(git merge-base --independent H) &&
+	git name-rev $parents >actual1.mb &&
+	parents=$(git merge-base --independent A H G) &&
+	git name-rev $parents >actual2.mb &&
+
+	parents=$(git show-branch --independent H) &&
+	git name-rev $parents >actual1.sb &&
+	parents=$(git show-branch --independent A H G) &&
+	git name-rev $parents >actual2.sb &&
+
+	test_cmp expected1 actual1.mb &&
+	test_cmp expected2 actual2.mb &&
+	test_cmp expected1 actual1.sb &&
+	test_cmp expected2 actual2.sb
+'
+
+test_expect_success 'unsynchronized clocks' '
+	# This test is to demonstrate that relying on timestamps in a distributed
+	# SCM to provide a _consistent_ partial ordering of commits leads to
+	# insanity.
+	#
+	#               Relative
+	# Structure     timestamps
+	#
+	#   PL  PR        +4  +4
+	#  /  \/  \      /  \/  \
+	# L2  C2  R2    +3  -1  +3
+	# |   |   |     |   |   |
+	# L1  C1  R1    +2  -2  +2
+	# |   |   |     |   |   |
+	# L0  C0  R0    +1  -3  +1
+	#   \ |  /        \ |  /
+	#     S             0
+	#
+	# The left and right chains of commits can be of any length and complexity as
+	# long as all of the timestamps are greater than that of S.
+
+	S=$(doit  0 S) &&
+
+	C0=$(doit -3 C0 $S) &&
+	C1=$(doit -2 C1 $C0) &&
+	C2=$(doit -1 C2 $C1) &&
+
+	L0=$(doit  1 L0 $S) &&
+	L1=$(doit  2 L1 $L0) &&
+	L2=$(doit  3 L2 $L1) &&
+
+	R0=$(doit  1 R0 $S) &&
+	R1=$(doit  2 R1 $R0) &&
+	R2=$(doit  3 R2 $R1) &&
+
+	PL=$(doit  4 PL $L2 $C2) &&
+	PR=$(doit  4 PR $C2 $R2) &&
+
+	git name-rev $C2 >expected &&
+
+	MB=$(git merge-base PL PR) &&
+	git name-rev "$MB" >actual.single &&
+
+	MB=$(git merge-base --all PL PR) &&
+	git name-rev "$MB" >actual.all &&
+
+	test_cmp expected actual.single &&
+	test_cmp expected actual.all
+'
+
+test_expect_success '--independent with unsynchronized clocks' '
+	IB=$(doit 0 IB) &&
+	I1=$(doit -10 I1 $IB) &&
+	I2=$(doit  -9 I2 $I1) &&
+	I3=$(doit  -8 I3 $I2) &&
+	I4=$(doit  -7 I4 $I3) &&
+	I5=$(doit  -6 I5 $I4) &&
+	I6=$(doit  -5 I6 $I5) &&
+	I7=$(doit  -4 I7 $I6) &&
+	I8=$(doit  -3 I8 $I7) &&
+	IH=$(doit  -2 IH $I8) &&
+
+	echo $IH >expected &&
+	git merge-base --independent IB IH >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'merge-base for octopus-step (setup)' '
+	# Another set to demonstrate base between one commit and a merge
+	# in the documentation.
+	#
+	# * C (MMC) * B (MMB) * A  (MMA)
+	# * o       * o       * o
+	# * o       * o       * o
+	# * o       * o       * o
+	# * o       | _______/
+	# |         |/
+	# |         * 1 (MM1)
+	# | _______/
+	# |/
+	# * root (MMR)
+
+	test_commit MMR &&
+	test_commit MM1 &&
+	test_commit MM-o &&
+	test_commit MM-p &&
+	test_commit MM-q &&
+	test_commit MMA &&
+	git checkout MM1 &&
+	test_commit MM-r &&
+	test_commit MM-s &&
+	test_commit MM-t &&
+	test_commit MMB &&
+	git checkout MMR &&
+	test_commit MM-u &&
+	test_commit MM-v &&
+	test_commit MM-w &&
+	test_commit MM-x &&
+	test_commit MMC
+'
+
+test_expect_success 'merge-base A B C' '
+	git rev-parse --verify MM1 >expected &&
+	git rev-parse --verify MMR >expected.sb &&
+
+	git merge-base --all MMA MMB MMC >actual &&
+	git merge-base --all --octopus MMA MMB MMC >actual.common &&
+	git show-branch --merge-base MMA MMB MMC >actual.sb &&
+
+	test_cmp expected actual &&
+	test_cmp expected.sb actual.common &&
+	test_cmp expected.sb actual.sb
+'
+
+test_expect_success 'criss-cross merge-base for octopus-step' '
+	git reset --hard MMR &&
+	test_commit CC1 &&
+	git reset --hard E &&
+	test_commit CC2 &&
+	test_tick &&
+	# E is a root commit unrelated to MMR root on which CC1 is based
+	git merge -s ours --allow-unrelated-histories CC1 &&
+	test_commit CC-o &&
+	test_commit CCB &&
+	git reset --hard CC1 &&
+	# E is a root commit unrelated to MMR root on which CC1 is based
+	git merge -s ours --allow-unrelated-histories CC2 &&
+	test_commit CCA &&
+
+	git rev-parse CC1 CC2 >expected &&
+	git merge-base --all CCB CCA^^ CCA^^2 >actual &&
+
+	sort expected >expected.sorted &&
+	sort actual >actual.sorted &&
+	test_cmp expected.sorted actual.sorted
+'
+
+test_expect_success 'using reflog to find the fork point' '
+	git reset --hard &&
+	git checkout -b base $E &&
+
+	(
+		for count in 1 2 3
+		do
+			git commit --allow-empty -m "Base commit #$count" &&
+			git rev-parse HEAD >expect$count &&
+			git checkout -B derived &&
+			git commit --allow-empty -m "Derived #$count" &&
+			git rev-parse HEAD >derived$count &&
+			git checkout -B base $E || exit 1
+		done &&
+
+		for count in 1 2 3
+		do
+			git merge-base --fork-point base $(cat derived$count) >actual &&
+			test_cmp expect$count actual || exit 1
+		done
+
+	) &&
+	# check that we correctly default to HEAD
+	git checkout derived &&
+	git merge-base --fork-point base >actual &&
+	test_cmp expect3 actual
+'
+
+test_expect_success '--fork-point works with empty reflog' '
+	git -c core.logallrefupdates=false branch no-reflog base &&
+	git merge-base --fork-point no-reflog derived &&
+	test_cmp expect3 actual
+'
+
+test_expect_success 'merge-base --octopus --all for complex tree' '
+	# Best common ancestor for JE, JAA and JDD is JC
+	#             JE
+	#            / |
+	#           /  |
+	#          /   |
+	#  JAA    /    |
+	#   |\   /     |
+	#   | \  | JDD |
+	#   |  \ |/ |  |
+	#   |   JC JD  |
+	#   |    | /|  |
+	#   |    |/ |  |
+	#  JA    |  |  |
+	#   |\  /|  |  |
+	#   X JB |  X  X
+	#   \  \ | /   /
+	#    \__\|/___/
+	#        J
+	test_commit J &&
+	test_commit JB &&
+	git reset --hard J &&
+	test_commit JC &&
+	git reset --hard J &&
+	test_commit JTEMP1 &&
+	test_merge JA JB &&
+	test_merge JAA JC &&
+	git reset --hard J &&
+	test_commit JTEMP2 &&
+	test_merge JD JB &&
+	test_merge JDD JC &&
+	git reset --hard J &&
+	test_commit JTEMP3 &&
+	test_merge JE JC &&
+	git rev-parse JC >expected &&
+	git merge-base --all --octopus JAA JDD JE >actual &&
+	test_cmp expected actual
+'
+
+test_done