[Codecov] Replace threshold:5 with informational:true

[wilzbach]

There are still many parts of Phobos which have a low coverage. Touching them shouldn't make a PR fail.

See also: dlang/phobos#6124

Example from #2079

codecov/patch — 21.052% of diff hit (target 74.653%)

Phobos and DMD already use this behavior.

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[MartinNowak]

Why? Patch coverage in #2079 was low due to a very technical reason (#2079 (comment)), which apparently wasn't understood by any of the reviewers. It seems that coverage rightly failed and should have been rightly overriden by a knowledagable reviewer.
I'm a bit picky here because informal usually means tests are ignored and there aren't any good reasons why a refactoring or newly added code would come without coverage.

Phobos and DMD already use this behavior.

Please reconsider, also it should be threshold: 5 + informal, so that the result at least still reflects the tolerance correctly.

[wilzbach]

It seems that coverage rightly failed and should have been rightly overriden by a knowledagable reviewer.

Yes, but I opened the PR, s.t. we can use auto-merge (failing CI!).

I'm a bit picky here because informal usually means tests are ignored and there aren't any good reasons why a refactoring or newly added code would come without coverage.

In experience with Phobos + DMD, it's very easy to get below the threshold.
The problem is that CodeCov doesn't take the coverage of the previous diff as threshold, but the overall project coverage.
Here's another example:

dlang/phobos#6041 (comment)

So if you touch the wrong file or function which isn't as covered as the overall project CodeCov would mark your PR as failed.

Please reconsider, also it should be threshold: 5 + informal, so that the result at least still reflects the tolerance correctly.

Almost all reviewers have the CodeCov extension installed and see the red lines directly on the diff.
Also as mentioned threshold doesn't work for diffs - seems like a "missing feature" from CodeCov.

[MartinNowak]

Almost all reviewers have the CodeCov extension installed and see the red lines directly on the diff.

Hope they soon manage to convert their plugin to a Firefox web extension.
codecov/browser-extension#44

Also as mentioned threshold doesn't work for diffs - seems like a "missing feature" from CodeCov.

Mmh, that's annoying.