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e379fdf34f
While it makes sense to allow merging unrelated histories of two projects that started independently into one, in the way "gitk" was merged to "git" itself aka "the coolest merge ever", such a merge is still an unusual event. Worse, if somebody creates an independent history by starting from a tarball of an established project and sends a pull request to the original project, "git merge" however happily creates such a merge without any sign of something unusual is happening. Teach "git merge" to refuse to create such a merge by default, unless the user passes a new "--allow-unrelated-histories" option to tell it that the user is aware that two unrelated projects are merged. Because such a "two project merge" is a rare event, a configuration option to always allow such a merge is not added. We could add the same option to "git pull" and have it passed through to underlying "git merge". I do not have a fundamental opposition against such a feature, but this commit does not do so and instead leaves it as low-hanging fruit for others, because such a "two project merge" would be done after fetching the other project into some location in the working tree of an existing project and making sure how well they fit together, it is sufficient to allow a local merge without such an option pass-through from "git pull" to "git merge". Many tests that are updated by this patch does the pass-through manually by turning: git pull something into its equivalent: git fetch something && git merge --allow-unrelated-histories FETCH_HEAD If somebody is inclined to add such an option, updated tests in this change need to be adjusted back to: git pull --allow-unrelated-histories something Signed-off-by: Junio C Hamano <gitster@pobox.com>
302 lines
6.9 KiB
Bash
Executable file
302 lines
6.9 KiB
Bash
Executable file
#!/bin/sh
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#
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# Copyright (c) 2005 Junio C Hamano
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#
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test_description='Merge base and parent list computation.
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'
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. ./test-lib.sh
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M=1130000000
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Z=+0000
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GIT_COMMITTER_EMAIL=git@comm.iter.xz
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GIT_COMMITTER_NAME='C O Mmiter'
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GIT_AUTHOR_NAME='A U Thor'
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GIT_AUTHOR_EMAIL=git@au.thor.xz
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export GIT_COMMITTER_EMAIL GIT_COMMITTER_NAME GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL
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doit () {
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OFFSET=$1 &&
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NAME=$2 &&
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shift 2 &&
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PARENTS= &&
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for P
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do
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PARENTS="${PARENTS}-p $P "
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done &&
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GIT_COMMITTER_DATE="$(($M + $OFFSET)) $Z" &&
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GIT_AUTHOR_DATE=$GIT_COMMITTER_DATE &&
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export GIT_COMMITTER_DATE GIT_AUTHOR_DATE &&
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commit=$(echo $NAME | git commit-tree $T $PARENTS) &&
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echo $commit >.git/refs/tags/$NAME &&
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echo $commit
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}
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test_expect_success 'setup' '
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T=$(git mktree </dev/null)
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'
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test_expect_success 'set up G and H' '
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# E---D---C---B---A
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# \"-_ \ \
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# \ `---------G \
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# \ \
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# F----------------H
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E=$(doit 5 E) &&
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D=$(doit 4 D $E) &&
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F=$(doit 6 F $E) &&
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C=$(doit 3 C $D) &&
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B=$(doit 2 B $C) &&
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A=$(doit 1 A $B) &&
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G=$(doit 7 G $B $E) &&
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H=$(doit 8 H $A $F)
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'
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test_expect_success 'merge-base G H' '
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git name-rev $B >expected &&
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MB=$(git merge-base G H) &&
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git name-rev "$MB" >actual.single &&
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MB=$(git merge-base --all G H) &&
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git name-rev "$MB" >actual.all &&
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MB=$(git show-branch --merge-base G H) &&
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git name-rev "$MB" >actual.sb &&
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test_cmp expected actual.single &&
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test_cmp expected actual.all &&
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test_cmp expected actual.sb
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'
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test_expect_success 'merge-base/show-branch --independent' '
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git name-rev "$H" >expected1 &&
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git name-rev "$H" "$G" >expected2 &&
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parents=$(git merge-base --independent H) &&
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git name-rev $parents >actual1.mb &&
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parents=$(git merge-base --independent A H G) &&
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git name-rev $parents >actual2.mb &&
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parents=$(git show-branch --independent H) &&
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git name-rev $parents >actual1.sb &&
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parents=$(git show-branch --independent A H G) &&
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git name-rev $parents >actual2.sb &&
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test_cmp expected1 actual1.mb &&
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test_cmp expected2 actual2.mb &&
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test_cmp expected1 actual1.sb &&
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test_cmp expected2 actual2.sb
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'
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test_expect_success 'unsynchronized clocks' '
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# This test is to demonstrate that relying on timestamps in a distributed
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# SCM to provide a _consistent_ partial ordering of commits leads to
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# insanity.
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#
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# Relative
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# Structure timestamps
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#
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# PL PR +4 +4
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# / \/ \ / \/ \
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# L2 C2 R2 +3 -1 +3
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# | | | | | |
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# L1 C1 R1 +2 -2 +2
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# | | | | | |
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# L0 C0 R0 +1 -3 +1
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# \ | / \ | /
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# S 0
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#
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# The left and right chains of commits can be of any length and complexity as
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# long as all of the timestamps are greater than that of S.
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S=$(doit 0 S) &&
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C0=$(doit -3 C0 $S) &&
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C1=$(doit -2 C1 $C0) &&
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C2=$(doit -1 C2 $C1) &&
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L0=$(doit 1 L0 $S) &&
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L1=$(doit 2 L1 $L0) &&
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L2=$(doit 3 L2 $L1) &&
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R0=$(doit 1 R0 $S) &&
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R1=$(doit 2 R1 $R0) &&
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R2=$(doit 3 R2 $R1) &&
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PL=$(doit 4 PL $L2 $C2) &&
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PR=$(doit 4 PR $C2 $R2) &&
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git name-rev $C2 >expected &&
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MB=$(git merge-base PL PR) &&
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git name-rev "$MB" >actual.single &&
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MB=$(git merge-base --all PL PR) &&
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git name-rev "$MB" >actual.all &&
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test_cmp expected actual.single &&
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test_cmp expected actual.all
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'
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test_expect_success '--independent with unsynchronized clocks' '
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IB=$(doit 0 IB) &&
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I1=$(doit -10 I1 $IB) &&
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I2=$(doit -9 I2 $I1) &&
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I3=$(doit -8 I3 $I2) &&
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I4=$(doit -7 I4 $I3) &&
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I5=$(doit -6 I5 $I4) &&
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I6=$(doit -5 I6 $I5) &&
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I7=$(doit -4 I7 $I6) &&
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I8=$(doit -3 I8 $I7) &&
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IH=$(doit -2 IH $I8) &&
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echo $IH >expected &&
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git merge-base --independent IB IH >actual &&
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test_cmp expected actual
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'
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test_expect_success 'merge-base for octopus-step (setup)' '
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# Another set to demonstrate base between one commit and a merge
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# in the documentation.
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#
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# * C (MMC) * B (MMB) * A (MMA)
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# * o * o * o
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# * o * o * o
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# * o * o * o
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# * o | _______/
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# | |/
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# | * 1 (MM1)
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# | _______/
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# |/
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# * root (MMR)
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test_commit MMR &&
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test_commit MM1 &&
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test_commit MM-o &&
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test_commit MM-p &&
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test_commit MM-q &&
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test_commit MMA &&
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git checkout MM1 &&
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test_commit MM-r &&
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test_commit MM-s &&
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test_commit MM-t &&
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test_commit MMB &&
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git checkout MMR &&
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test_commit MM-u &&
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test_commit MM-v &&
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test_commit MM-w &&
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test_commit MM-x &&
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test_commit MMC
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'
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test_expect_success 'merge-base A B C' '
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git rev-parse --verify MM1 >expected &&
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git rev-parse --verify MMR >expected.sb &&
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git merge-base --all MMA MMB MMC >actual &&
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git merge-base --all --octopus MMA MMB MMC >actual.common &&
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git show-branch --merge-base MMA MMB MMC >actual.sb &&
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test_cmp expected actual &&
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test_cmp expected.sb actual.common &&
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test_cmp expected.sb actual.sb
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'
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test_expect_success 'criss-cross merge-base for octopus-step' '
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git reset --hard MMR &&
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test_commit CC1 &&
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git reset --hard E &&
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test_commit CC2 &&
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test_tick &&
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# E is a root commit unrelated to MMR root on which CC1 is based
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git merge -s ours --allow-unrelated-histories CC1 &&
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test_commit CC-o &&
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test_commit CCB &&
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git reset --hard CC1 &&
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# E is a root commit unrelated to MMR root on which CC1 is based
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git merge -s ours --allow-unrelated-histories CC2 &&
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test_commit CCA &&
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git rev-parse CC1 CC2 >expected &&
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git merge-base --all CCB CCA^^ CCA^^2 >actual &&
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sort expected >expected.sorted &&
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sort actual >actual.sorted &&
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test_cmp expected.sorted actual.sorted
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'
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test_expect_success 'using reflog to find the fork point' '
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git reset --hard &&
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git checkout -b base $E &&
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(
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for count in 1 2 3
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do
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git commit --allow-empty -m "Base commit #$count" &&
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git rev-parse HEAD >expect$count &&
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git checkout -B derived &&
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git commit --allow-empty -m "Derived #$count" &&
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git rev-parse HEAD >derived$count &&
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git checkout -B base $E || exit 1
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done
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for count in 1 2 3
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do
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git merge-base --fork-point base $(cat derived$count) >actual &&
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test_cmp expect$count actual || exit 1
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done
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) &&
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# check that we correctly default to HEAD
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git checkout derived &&
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git merge-base --fork-point base >actual &&
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test_cmp expect3 actual
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'
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test_expect_success 'merge-base --octopus --all for complex tree' '
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# Best common ancestor for JE, JAA and JDD is JC
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# JE
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# / |
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# / |
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# / |
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# JAA / |
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# |\ / |
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# | \ | JDD |
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# | \ |/ | |
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# | JC JD |
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# | | /| |
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# | |/ | |
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# JA | | |
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# |\ /| | |
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# X JB | X X
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# \ \ | / /
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# \__\|/___/
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# J
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test_commit J &&
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test_commit JB &&
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git reset --hard J &&
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test_commit JC &&
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git reset --hard J &&
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test_commit JTEMP1 &&
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test_merge JA JB &&
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test_merge JAA JC &&
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git reset --hard J &&
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test_commit JTEMP2 &&
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test_merge JD JB &&
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test_merge JDD JC &&
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git reset --hard J &&
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test_commit JTEMP3 &&
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test_merge JE JC &&
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git rev-parse JC >expected &&
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git merge-base --all --octopus JAA JDD JE >actual &&
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test_cmp expected actual
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'
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test_done
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