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ed84bc1c0d
git-cherry(1) links to this command. These two commands are similar and we also mention it in the “Examples” section now. Let’s link to it. Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name> Signed-off-by: Junio C Hamano <gitster@pobox.com>
118 lines
3.6 KiB
Plaintext
118 lines
3.6 KiB
Plaintext
git-patch-id(1)
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===============
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NAME
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----
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git-patch-id - Compute unique IDs for patches
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SYNOPSIS
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--------
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[synopsis]
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git patch-id [--stable | --unstable | --verbatim]
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DESCRIPTION
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-----------
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Read patches from standard input and compute the patch IDs.
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A "patch ID" is nothing but a sum of SHA-1 of the file diffs associated with a
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patch, with line numbers ignored. As such, it's "reasonably stable", but at
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the same time also reasonably unique, i.e., two patches that have the same
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"patch ID" are almost guaranteed to be the same thing.
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The main usecase for this command is to look for likely duplicate commits.
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When dealing with `git diff-tree --patch` output, it takes advantage of
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the fact that the patch is prefixed with the object name of the
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commit, and outputs two 40-byte hexadecimal strings. The first
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string is the patch ID, and the second string is the commit ID.
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This can be used to make a mapping from patch ID to commit ID for a
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set or range of commits.
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OPTIONS
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-------
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`--verbatim`::
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Calculate the patch ID of the input as it is given, do not strip
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any whitespace. Implies `--stable` and forbids `--unstable`.
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+
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This is the default if `patchid.verbatim` is `true`.
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`--stable`::
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Use a "stable" sum of hashes as the patch ID. With this option:
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+
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--
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- Reordering file diffs that make up a patch does not affect the ID.
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In particular, two patches produced by comparing the same two trees
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with two different settings for `-O<orderfile>` result in the same
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patch ID signature, thereby allowing the computed result to be used
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as a key to index some meta-information about the change between
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the two trees.
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- The result is different from the value produced by Git 1.9 and older
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or produced when an "unstable" hash (see `--unstable` below) is
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configured - even when used on a diff output taken without any use
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of `-O<orderfile>`, thereby making existing databases storing such
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"unstable" or historical patch IDs unusable.
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- All whitespace within the patch is ignored and does not affect the ID.
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--
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+
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This is the default if `patchid.stable` is set to `true`.
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`--unstable`::
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Use an "unstable" hash as the patch ID. With this option,
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the result produced is compatible with the patch ID value produced
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by Git 1.9 and older and whitespace is ignored. Users with pre-existing
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databases storing patch IDs produced by Git 1.9 and older (who do not deal
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with reordered patches) may want to use this option.
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+
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This is the default.
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EXAMPLES
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--------
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linkgit:git-cherry[1] shows what commits from a branch have patch ID
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equivalent commits in some upstream branch. But it only tells you
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whether such a commit exists or not. What if you wanted to know the
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relevant commits in the upstream? We can use this command to make a
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mapping between your branch and the upstream branch:
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----
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#!/bin/sh
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upstream="$1"
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branch="$2"
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test -z "$branch" && branch=HEAD
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limit="$3"
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if test -n "$limit"
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then
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tail_opts="$limit".."$upstream"
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else
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since=$(git log --format=%aI "$upstream".."$branch" | tail -1)
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tail_opts=--since="$since"' '"$upstream"
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fi
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for_branch=$(mktemp)
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for_upstream=$(mktemp)
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git rev-list --no-merges "$upstream".."$branch" |
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git diff-tree --patch --stdin |
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git patch-id --stable | sort >"$for_branch"
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git rev-list --no-merges $tail_opts |
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git diff-tree --patch --stdin |
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git patch-id --stable | sort >"$for_upstream"
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join -a1 "$for_branch" "$for_upstream" | cut -d' ' -f2,3
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rm "$for_branch"
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rm "$for_upstream"
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----
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Now the first column shows the commit from your branch and the second
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column shows the patch ID equivalent commit, if it exists.
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SEE ALSO
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--------
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linkgit:git-cherry[1]
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GIT
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---
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Part of the linkgit:git[1] suite
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