xref: /aosp_15_r20/external/cronet/third_party/libc++/src/utils/clang-format-merge-driver.sh (revision 6777b5387eb2ff775bb5750e3f5d96f37fb7352b)
1#!/usr/bin/env bash
2
3# This script can be installed in .git/config to allow rebasing old patches across
4# libc++'s clang-format of the whole tree. Most contributors should not require that
5# since they don't have many pre-clang-format patches lying around. This script is to
6# make it easier for contributors that do have such patches.
7#
8# The script is installed by running the following from the root of your repository:
9#
10#   $ git config merge.libcxx-reformat.name "Run clang-format when rebasing libc++ patches"
11#   $ git config merge.libcxx-reformat.driver "libcxx/utils/clang-format-merge-driver.sh %O %A %B %P"
12#
13# This is based on https://github.com/nico/hack/blob/main/notes/auto_git_rebase_across_mechanical_changes.md.
14# Many thanks to Nico Weber for paving the way here.
15
16# Path to the file's contents at the ancestor's version.
17base="$1"
18
19# Path to the file's contents at the current version.
20current="$2"
21
22# Path to the file's contents at the other branch's version (for nonlinear histories, there might be multiple other branches).
23other="$3"
24
25# The path of the file in the repository.
26path="$4"
27
28clang-format --style=file --assume-filename="$path" < "$base" > "$base.tmp"
29mv "$base.tmp" "$base"
30
31clang-format --style=file --assume-filename="$path" < "$current" > "$current.tmp"
32mv "$current.tmp" "$current"
33
34clang-format --style=file --assume-filename="$path" < "$other" > "$other.tmp"
35mv "$other.tmp" "$other"
36
37git merge-file -Lcurrent -Lbase -Lother "$current" "$base" "$other"
38