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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 09:49:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 09:49:36 +0000 |
commit | 5ec6074f0633939fd17d94111d10c6c6b062978c (patch) | |
tree | bfaa17b5a64abc66c918e9c70969e519d9e1df8e /Documentation/howto/separating-topic-branches.txt | |
parent | Initial commit. (diff) | |
download | git-upstream.tar.xz git-upstream.zip |
Adding upstream version 1:2.30.2.upstream/1%2.30.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/howto/separating-topic-branches.txt')
-rw-r--r-- | Documentation/howto/separating-topic-branches.txt | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/Documentation/howto/separating-topic-branches.txt b/Documentation/howto/separating-topic-branches.txt new file mode 100644 index 0000000..81be0d6 --- /dev/null +++ b/Documentation/howto/separating-topic-branches.txt @@ -0,0 +1,94 @@ +From: Junio C Hamano <gitster@pobox.com> +Subject: Separating topic branches +Abstract: In this article, JC describes how to separate topic branches. +Content-type: text/asciidoc + +How to separate topic branches +============================== + +This text was originally a footnote to a discussion about the +behaviour of the git diff commands. + +Often I find myself doing that [running diff against something other +than HEAD] while rewriting messy development history. For example, I +start doing some work without knowing exactly where it leads, and end +up with a history like this: + + "master" + o---o + \ "topic" + o---o---o---o---o---o + +At this point, "topic" contains something I know I want, but it +contains two concepts that turned out to be completely independent. +And often, one topic component is larger than the other. It may +contain more than two topics. + +In order to rewrite this mess to be more manageable, I would first do +"diff master..topic", to extract the changes into a single patch, start +picking pieces from it to get logically self-contained units, and +start building on top of "master": + + $ git diff master..topic >P.diff + $ git checkout -b topicA master + ... pick and apply pieces from P.diff to build + ... commits on topicA branch. + + o---o---o + / "topicA" + o---o"master" + \ "topic" + o---o---o---o---o---o + +Before doing each commit on "topicA" HEAD, I run "diff HEAD" +before update-index the affected paths, or "diff --cached HEAD" +after. Also I would run "diff --cached master" to make sure +that the changes are only the ones related to "topicA". Usually +I do this for smaller topics first. + +After that, I'd do the remainder of the original "topic", but +for that, I do not start from the patchfile I extracted by +comparing "master" and "topic" I used initially. Still on +"topicA", I extract "diff topic", and use it to rebuild the +other topic: + + $ git diff -R topic >P.diff ;# --cached also would work fine + $ git checkout -b topicB master + ... pick and apply pieces from P.diff to build + ... commits on topicB branch. + + "topicB" + o---o---o---o---o + / + /o---o---o + |/ "topicA" + o---o"master" + \ "topic" + o---o---o---o---o---o + +After I am done, I'd try a pretend-merge between "topicA" and +"topicB" in order to make sure I have not missed anything: + + $ git pull . topicA ;# merge it into current "topicB" + $ git diff topic + "topicB" + o---o---o---o---o---* (pretend merge) + / / + /o---o---o----------' + |/ "topicA" + o---o"master" + \ "topic" + o---o---o---o---o---o + +The last diff better not to show anything other than cleanups +for cruft. Then I can finally clean things up: + + $ git branch -D topic + $ git reset --hard HEAD^ ;# nuke pretend merge + + "topicB" + o---o---o---o---o + / + /o---o---o + |/ "topicA" + o---o"master" |