git-diff: --ignore-matching-lines has no effect on the output when --name-only is used

From: hi@arnes.space <hi@arnes.space>
Date: Jul 23, 2025, 05:47 UTC
Message-ID: <87a54v8nmz.fsf@arnes.space>

I discovered that diff output is not filtered when the `--name-only` flag is given, it always lists all affected files. Is this a known bug? I could not find anything in the documentation.

Perhaps related, `--ignore-matching-lines` is ignored by my external diff helper difftastic[1]. I'm not sure if this is an upstream issue, or if the way external diff helpers are implemented is related to this at all.

The behavior can be observed in git 2.49.0 using `git diff --no-ext-diff --name-only --ignore-matching-lines`.

Best, Arne

[1]: https://difftastic.wilfred.me.uk/

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.