Re: [PATCH] blame: respect .git-blame-ignore-revs automatically
From: Kristoffer Haugsbakk <hidden>
Date: 2024-10-08 09:08:02
Thank you for working on this. I think an ability to respect a conventional ignore list would be useful. I was a bit concerned that there doesn’t seem to be something to turn off ignore lists. The man page says that the discussed option exists but not some `--no` variant. But then I tested this:
git blame --ignore-revs-file=README.md \
--no-ignore-revs-file README.md
And that works without giving errors. So it’s there. Just apparently undocumented? My assumption then is that, with this change, I could use `--no-ignore-revs-file` to turn off the default file. (One can also use the config `blame.ignoreRevsFile` set to the empty string) On Tue, Oct 8, 2024, at 09:01, Abhijeetsingh Meena via GitGitGadget wrote:
From: Abhijeetsingh Meena <redacted> Modify `git blame` to automatically respect a `.git-blame-ignore-revs` file if it exists in the repository. This file is used by many projects to ignore non-functional changes, such as reformatting or large-scale refactoring, when generating blame information.
Nice.
Before this change, users had to manually specify the file with the `--ignore-revs-file` option. This update streamlines the process by automatically detecting the `.git-blame-ignore-revs` file, reducing manual effort.
(They can also use the `blame.ignoreRevsFile` config in order to not
have to give the option every time)
The project convention is to use the present tense for describing the
current behavior (without this patch). Like:
Users that have a standard list of commits to ignore have to use
`--ignore-revs-file`.
This style often lends itself to this structure:
- (optionally introduce the wider topic)
- Describe the current behavior and why that is a problem
- Say how we’re changing the code (which you already did a good job of in
your first paragraph).
It might end up something like this:
git-blame(1) can ignore a list of commits with `--ignore-revs-file`.
This is useful for marking uninteresting commits like formatting
changes, refactors and whatever else should not be “blamed”. Some
projects even version control this file so that all contributors can
use it; the conventional name is `.git-blame-ignore-revs`.
But each user still has to opt-in to the standard ignore list,
either with this option or with the config `blame.ignoreRevsFile`.
Let’s teach git-blame(1) to respect this conventional file in order
to streamline the process.
This change aligns with the standardized practice in many repositories
and simplifies the workflow for users.
Signed-off-by: Abhijeetsingh Meena <redacted>
---
blame: respect .git-blame-ignore-revs automatically
Introduction
============
Hi, I'm Abhijeet (Ethan0456), and this is my first contribution to the
Git project. I currently work as an ML Engineer at an early-stage
startup, and I’m excited to contribute to this open-source project.
Why the Change?
===============
I came across this enhancement request on the bug tracker and found it
beginner-friendly, making it a great opportunity for me to get familiar
with the Git codebase. The ability for git blame to automatically
respect the .git-blame-ignore-revs file is something that can streamline
workflows for many users, and I felt it would be a valuable addition.The issue that is referred: https://github.com/gitgitgadget/git/issues/1494 That issue tracker is unofficial by the way.
Feedback
========
While I’m confident in the changes made to builtin/blame.c and the new
test case in t/t8015-blame-ignore-revs.sh, I welcome any feedback or
suggestions to improve both my code and approach. I’m eager to learn
from the community and improve where needed.
Community Need
==============
There is precedent for this functionality in other projects:
* Chromium
[https://chromium.googlesource.com/chromium/src.git/+/f0596779e57f46fccb115a0fd65f0305894e3031/.git-blame-ignore-revs],
which powers many popular browsers, uses .git-blame-ignore-revs
to
simplify the blame process by ignoring non-functional changes.
* Rob Allen's blog post
[https://akrabat.com/ignoring-revisions-with-git-blame/]
discusses
the need for ignoring revisions with git blame, and a commenter
specifically suggests that it would be helpful if Git
automatically
respected .git-blame-ignore-revs.
I hope this change aligns with community needs and improves the git
blame experience for users.It’s nice that you mention specific projects that use this convention. Sometimes people just say “this is used by many people/projects”. But not what projects. (Then perhaps it is eventually revealed that “we use it so therefore it is important” ;) )
quoted hunk ↗ jump to hunk
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1809%2FEthan0456%2Fblame-auto-ignore-revs-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1809/Ethan0456/blame-auto-ignore-revs-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/1809 builtin/blame.c | 8 ++++++++ t/t8015-blame-default-ignore-revs.sh | 26 ++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) create mode 100755 t/t8015-blame-default-ignore-revs.shdiff --git a/builtin/blame.c b/builtin/blame.c index e407a22da3b..1eddabaf60f 100644 --- a/builtin/blame.c +++ b/builtin/blame.c@@ -1105,6 +1105,14 @@ parse_done: add_pending_object(&revs, &head_commit->object, "HEAD"); } + /* + * By default, add .git-blame-ignore-revs to the list of files + * containing revisions to ignore if it exists. + */ + if (access(".git-blame-ignore-revs", F_OK) == 0) { + string_list_append(&ignore_revs_file_list, ".git-blame-ignore-revs"); + } + init_scoreboard(&sb); sb.revs = &revs; sb.contents_from = contents_from;diff --git a/t/t8015-blame-default-ignore-revs.shb/t/t8015-blame-default-ignore-revs.sh new file mode 100755 index 00000000000..84e1a9e87e6--- /dev/null +++ b/t/t8015-blame-default-ignore-revs.sh@@ -0,0 +1,26 @@ +#!/bin/sh + +test_description='default revisions to ignore when blaming' + +TEST_PASSES_SANITIZE_LEAK=true +. ./test-lib.sh + +test_expect_success 'blame: default-ignore-revs-file' ' + test_commit first-commit hello.txt hello && + + echo world >>hello.txt && + test_commit second-commit hello.txt && + + sed "1s/hello/hi/" <hello.txt > hello.txt.tmp && + mv hello.txt.tmp hello.txt && + test_commit third-commit hello.txt && + + git rev-parse HEAD >ignored-file && + git blame --ignore-revs-file=ignored-file hello.txt >expect && + git rev-parse HEAD >.git-blame-ignore-revs && + git blame hello.txt >actual && + + test_cmp expect actual +' + +test_done\ No newline at end of file
There should be a final newline. ;)
base-commit: 777489f9e09c8d0dd6b12f9d90de6376330577a2 -- gitgitgadget