git-patch-id(1) — Linux manual page


GIT-PATCH-ID(1)                Git Manual                GIT-PATCH-ID(1)

NAME         top

       git-patch-id - Compute unique ID for a patch

SYNOPSIS         top

       git patch-id [--stable | --unstable]

DESCRIPTION         top

       Read a patch from the standard input and compute the patch ID for

       A "patch ID" is nothing but a sum of SHA-1 of the file diffs
       associated with a patch, with whitespace and line numbers
       ignored. As such, it’s "reasonably stable", but at the same time
       also reasonably unique, i.e., two patches that have the same
       "patch ID" are almost guaranteed to be the same thing.

       IOW, you can use this thing to look for likely duplicate commits.

       When dealing with git diff-tree output, it takes advantage of the
       fact that the patch is prefixed with the object name of the
       commit, and outputs two 40-byte hexadecimal strings. The first
       string is the patch ID, and the second string is the commit ID.
       This can be used to make a mapping from patch ID to commit ID.

OPTIONS         top

           Use a "stable" sum of hashes as the patch ID. With this

           •   Reordering file diffs that make up a patch does not
               affect the ID. In particular, two patches produced by
               comparing the same two trees with two different settings
               for "-O<orderfile>" result in the same patch ID
               signature, thereby allowing the computed result to be
               used as a key to index some meta-information about the
               change between the two trees;

           •   Result is different from the value produced by git 1.9
               and older or produced when an "unstable" hash (see
               --unstable below) is configured - even when used on a
               diff output taken without any use of "-O<orderfile>",
               thereby making existing databases storing such "unstable"
               or historical patch-ids unusable.

                   This is the default if patchid.stable is set to true.

           Use an "unstable" hash as the patch ID. With this option, the
           result produced is compatible with the patch-id value
           produced by git 1.9 and older. Users with pre-existing
           databases storing patch-ids produced by git 1.9 and older
           (who do not deal with reordered patches) may want to use this

               This is the default.

GIT         top

       Part of the git(1) suite

COLOPHON         top

       This page is part of the git (Git distributed version control
       system) project.  Information about the project can be found at
       ⟨⟩.  If you have a bug report for this manual
       page, see ⟨⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on 2021-08-27.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2021-08-24.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Git         08/27/2021                GIT-PATCH-ID(1)

Pages that refer to this page: git(1)git-cherry(1)git-range-diff(1)