Is there a way to ask git diff to show the method name instead of the class name?

If you find yourself having this issue, it might be due to the fact that git lets diff define the hunk header. If you want to force git to use its predefined ones for PHP place the following line in either .gitattributes in the root folder of your git repository or the .git/info/attributes file in your repository:

*.php diff=php

(Other languages are similarly supported. A list of the built in patterns is available in the documentation.)

Setting this Globally

It should be possible to globally set this by doing the following in git version >= 1.4

1. Put line(s) in ~/.gitattributes
2. Run git config --global core.attributesfile "~/.gitattributes"

Or if you want to set this globally

1. Put line(s) into /etc/gitattributes

Warning: If you personally set this globally, your peers may get different results when running git diff since they won't checkout a copy of .gitattributes with the repository.

I don't quite understand why it doesn't work the way it should.

As a temporary solution, add the following to .gitattributes:

*.php   diff=phpf

And these lines to .git/config or ~/.gitconfig:

[diff "phpf"]        xfuncname = "^[\t ]*(((public|protected|private|static)[\t ]+)*function.*)$"

For a permanent solution ask Git developers directly at git@vger.kernel.org mailing list.

That diff would likely be better with Git 2.19 (Q3 2018), since the userdiff pattern for .php has been updated.

See commit 1ab6316, commit 9992fbd (03 Jul 2018) by Kana Natsuno (kana).
^{(Merged by Junio C Hamano -- gitster -- in commit d3f0938, 24 Jul 2018)}

userdiff: support new keywords in PHP hunk header

Recent version of PHP supports interface, trait, abstract class andfinal class.
This patch fixes the PHP hunk header regexp to support all of these keywords.

And it does improve with Git 2.30 (Q1 2021):

See commit aff9282 (07 Oct 2020) by Javier Spagnoletti (phansys).
^{(Merged by Junio C Hamano -- gitster -- in commit a8a49eb, 27 Oct 2020)}

userdiff: PHP: catch "abstract" and "final" functions

^{Helped-by: Johannes Sixt
Signed-off-by: Javier Spagnoletti}

PHP permits functions to be defined like

final public function foo() { }abstract protected function bar() { }  

but our hunk header pattern does not recognize these decorations.

Add "final" and "abstract" to the list of function modifiers.