| 1 | #!/bin/sh |
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| 2 | # |
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| 3 | # Copyright (c) 2006 Junio C Hamano |
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| 4 | # |
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| 5 | |
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| 6 | publish=next |
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| 7 | basebranch="$1" |
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| 8 | if test "$#" = 2 |
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| 9 | then |
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| 10 | topic="refs/heads/$2" |
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| 11 | else |
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| 12 | topic=`git symbolic-ref HEAD` |
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| 13 | fi |
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| 14 | |
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| 15 | case "$basebranch,$topic" in |
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| 16 | master,refs/heads/??/*) |
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| 17 | ;; |
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| 18 | *) |
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| 19 | exit 0 ;# we do not interrupt others. |
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| 20 | ;; |
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| 21 | esac |
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| 22 | |
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| 23 | # Now we are dealing with a topic branch being rebased |
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| 24 | # on top of master. Is it OK to rebase it? |
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| 25 | |
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| 26 | # Is topic fully merged to master? |
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| 27 | not_in_master=`git-rev-list --pretty=oneline ^master "$topic"` |
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| 28 | if test -z "$not_in_master" |
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| 29 | then |
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| 30 | echo >&2 "$topic is fully merged to master; better remove it." |
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| 31 | exit 1 ;# we could allow it, but there is no point. |
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| 32 | fi |
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| 33 | |
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| 34 | # Is topic ever merged to next? If so you should not be rebasing it. |
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| 35 | only_next_1=`git-rev-list ^master "^$topic" ${publish} | sort` |
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| 36 | only_next_2=`git-rev-list ^master ${publish} | sort` |
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| 37 | if test "$only_next_1" = "$only_next_2" |
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| 38 | then |
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| 39 | not_in_topic=`git-rev-list "^$topic" master` |
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| 40 | if test -z "$not_in_topic" |
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| 41 | then |
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| 42 | echo >&2 "$topic is already up-to-date with master" |
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| 43 | exit 1 ;# we could allow it, but there is no point. |
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| 44 | else |
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| 45 | exit 0 |
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| 46 | fi |
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| 47 | else |
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| 48 | not_in_next=`git-rev-list --pretty=oneline ^${publish} "$topic"` |
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| 49 | perl -e ' |
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| 50 | my $topic = $ARGV[0]; |
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| 51 | my $msg = "* $topic has commits already merged to public branch:\n"; |
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| 52 | my (%not_in_next) = map { |
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| 53 | /^([0-9a-f]+) /; |
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| 54 | ($1 => 1); |
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| 55 | } split(/\n/, $ARGV[1]); |
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| 56 | for my $elem (map { |
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| 57 | /^([0-9a-f]+) (.*)$/; |
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| 58 | [$1 => $2]; |
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| 59 | } split(/\n/, $ARGV[2])) { |
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| 60 | if (!exists $not_in_next{$elem->[0]}) { |
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| 61 | if ($msg) { |
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| 62 | print STDERR $msg; |
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| 63 | undef $msg; |
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| 64 | } |
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| 65 | print STDERR " $elem->[1]\n"; |
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| 66 | } |
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| 67 | } |
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| 68 | ' "$topic" "$not_in_next" "$not_in_master" |
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| 69 | exit 1 |
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| 70 | fi |
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| 71 | |
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| 72 | exit 0 |
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| 73 | |
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| 74 | ################################################################ |
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| 75 | |
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| 76 | This sample hook safeguards topic branches that have been |
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| 77 | published from being rewound. |
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| 78 | |
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| 79 | The workflow assumed here is: |
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| 80 | |
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| 81 | * Once a topic branch forks from "master", "master" is never |
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| 82 | merged into it again (either directly or indirectly). |
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| 83 | |
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| 84 | * Once a topic branch is fully cooked and merged into "master", |
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| 85 | it is deleted. If you need to build on top of it to correct |
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| 86 | earlier mistakes, a new topic branch is created by forking at |
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| 87 | the tip of the "master". This is not strictly necessary, but |
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| 88 | it makes it easier to keep your history simple. |
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| 89 | |
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| 90 | * Whenever you need to test or publish your changes to topic |
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| 91 | branches, merge them into "next" branch. |
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| 92 | |
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| 93 | The script, being an example, hardcodes the publish branch name |
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| 94 | to be "next", but it is trivial to make it configurable via |
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| 95 | $GIT_DIR/config mechanism. |
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| 96 | |
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| 97 | With this workflow, you would want to know: |
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| 98 | |
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| 99 | (1) ... if a topic branch has ever been merged to "next". Young |
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| 100 | topic branches can have stupid mistakes you would rather |
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| 101 | clean up before publishing, and things that have not been |
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| 102 | merged into other branches can be easily rebased without |
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| 103 | affecting other people. But once it is published, you would |
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| 104 | not want to rewind it. |
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| 105 | |
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| 106 | (2) ... if a topic branch has been fully merged to "master". |
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| 107 | Then you can delete it. More importantly, you should not |
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| 108 | build on top of it -- other people may already want to |
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| 109 | change things related to the topic as patches against your |
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| 110 | "master", so if you need further changes, it is better to |
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| 111 | fork the topic (perhaps with the same name) afresh from the |
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| 112 | tip of "master". |
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| 113 | |
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| 114 | Let's look at this example: |
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| 115 | |
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| 116 | o---o---o---o---o---o---o---o---o---o "next" |
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| 117 | / / / / |
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| 118 | / a---a---b A / / |
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| 119 | / / / / |
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| 120 | / / c---c---c---c B / |
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| 121 | / / / \ / |
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| 122 | / / / b---b C \ / |
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| 123 | / / / / \ / |
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| 124 | ---o---o---o---o---o---o---o---o---o---o---o "master" |
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| 125 | |
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| 126 | |
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| 127 | A, B and C are topic branches. |
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| 128 | |
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| 129 | * A has one fix since it was merged up to "next". |
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| 130 | |
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| 131 | * B has finished. It has been fully merged up to "master" and "next", |
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| 132 | and is ready to be deleted. |
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| 133 | |
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| 134 | * C has not merged to "next" at all. |
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| 135 | |
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| 136 | We would want to allow C to be rebased, refuse A, and encourage |
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| 137 | B to be deleted. |
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| 138 | |
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| 139 | To compute (1): |
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| 140 | |
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| 141 | git-rev-list ^master ^topic next |
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| 142 | git-rev-list ^master next |
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| 143 | |
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| 144 | if these match, topic has not merged in next at all. |
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| 145 | |
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| 146 | To compute (2): |
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| 147 | |
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| 148 | git-rev-list master..topic |
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| 149 | |
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| 150 | if this is empty, it is fully merged to "master". |
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