grepdiff1 test fails on musl

[alyssais]

musl does not accept the regex \+a used in the grepdiff1 test. + doesn't have special meaning in POSIX regular expressions if it's at the start of the expression. So the POSIX way to write that regular expression would be +a.

However, this is actually what the test used to do, until it was changed in a653875 with no explanation given. What was the motivation for that change?

[twaugh]

I don't remember :(

I wonder if that test is still useful. WDYT?

[alyssais]

It looks like grepdiff has lots of other test coverage? But I'm not too familiar with what it even does — I'm mostly interested in patchutils for filterdiff.