[Build] Fix skipping tests when there are only documentation changes and run centos7 & windows cpp build only when there are cpp changes

[lhotari]

Fixes #10373

Motivation

Tests should be skipped for PR builds that only contain documentation changes. This is currently broken.

A new build has been introduced for building the CPP client on Windows. Make the changes in ci-cpp-build-centos7.yaml and ci-cpp-build-windows.yaml so that the builds run only when there are changes in CPP client files (or the workflow definitions).

Modifications

Refactor logic to be less error prone. Use fromJSON function to parse a number in a string as a number.

Additional Context

#10276

[lhotari]

@michaeljmarshall @eolivelli @aahmed-se Please review

[eolivelli]

+1

@aahmed-se @merlimat PTAL

[michaeljmarshall]

LGTM

[lhotari]

this seems complex, but it's necessary.

picomatch translates a pattern to a regex under the covers. combining including and excluding can lead to odd results.

It's possible to test picomatch patterns using npm on the command line, for example:

# check picomatch version from https://github.com/apache/pulsar-test-infra/blob/master/paths-filter/package-lock.json
npm install picomatch@2.2.1  
function test_picomatch_pattern() { node -e 'const pattern=process.argv[1]; const matcher=require("picomatch")(pattern, {"dot": true}); console.log(`pattern: ${pattern}`); process.argv.splice(2).forEach(arg => console.log(`${arg} -> ${matcher(arg)}`));' "$@"  }

test_picomatch_pattern '**/*.md' README.md some/path/README.md

This example shows a problem with inversion (!) in the pattern:

❯ test_picomatch_pattern '**/*.md' README.md some/path/README.md
pattern: **/*.md
README.md -> true
some/path/README.md -> true
❯ test_picomatch_pattern '!(**/*.md)' README.md some/path/README.md
pattern: !(**/*.md)
README.md -> true
some/path/README.md -> false

That is the reason why the logic for checking documentation only changes is done based on the comparison on match counts,
fromJSON(steps.changes.outputs.all_count) == fromJSON(steps.changes.outputs.docs_count) && fromJSON(steps.changes.outputs.docs_count) > 0 .

[lhotari]

paths-ignore would be fine here, but it's removed to be consistent with other workflows in apache/pulsar where paths-filter action (copy of https://github.com/dorny/paths-filter) is used.

GitHub provides a paths-ignore feature out of the box.
However, GitHub's paths-ignore has some limitations:

• GitHub's paths-ignore fails to look at previous commits. This means that the outcome depends on how often you push changes.
• Consequently, GitHub's paths-ignore does not work for required checks.
  If you path-ignore a required check, then pull requests will block forever without being mergeable.

(source)

paths-ignore was once used in apache/pulsar (introduced by #9527), but it had to be reverted in #9606 because of the limitations.

[lhotari]

/pulsarbot run-failure-checks