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d96855ff51
The "git pull --rebase" command computes the fork point of the
branch being rebased using the reflog entries of the "base" branch
(typically a remote-tracking branch) the branch's work was based on,
in order to cope with the case in which the "base" branch has been
rewound and rebuilt. For example, if the history looked like this:
o---B1
/
---o---o---B2--o---o---o---Base
\
B3
\
Derived
where the current tip of the "base" branch is at Base, but earlier
fetch observed that its tip used to be B3 and then B2 and then B1
before getting to the current commit, and the branch being rebased
on top of the latest "base" is based on commit B3, it tries to find
B3 by going through the output of "git rev-list --reflog base" (i.e.
Base, B1, B2, B3) until it finds a commit that is an ancestor of the
current tip "Derived".
Internally, we have get_merge_bases_many() that can compute this
with one-go. We would want a merge-base between Derived and a
fictitious merge commit that would result by merging all the
historical tips of "base". When such a commit exist, we should get
a single result, which exactly match one of the reflog entries of
"base".
Teach "git merge-base" a new mode, "--fork-point", to compute
exactly that.
Helped-by: Martin von Zweigbergk <martinvonz@gmail.com>
Helped-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
262 lines
5.9 KiB
Bash
Executable file
262 lines
5.9 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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git merge -s ours 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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git merge -s ours 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_done
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