Fix fail-on-error to handle all installation and execution failures

[Copilot]

Fixes

• fail-on-error doesn't work well when download fails #253

When binary downloads fail with fail-on-error: false, the installation exits cleanly but subsequent steps attempt to execute the missing coveralls command, causing "command not found" errors that break CI workflows.

Changes

Installation error handling

• macOS: Added fail-on-error checks for brew install failures and missing binary
• Linux: Added fail-on-error check for missing binary after extraction
• Windows: Wrapped downloads in try-catch, added fail-on-error checks for checksum verification and missing binary

Execution safeguards

• Split coverage report steps by OS (Unix/Windows) to handle shell differences
• Added binary existence checks before executing coveralls commands
• Exit cleanly with code 0 when binary missing and fail-on-error: false

Example

When installation fails:

# Before: Installation fails silently, then coverage step crashes
Failed to download coveralls binary or checksum (Linux).
coveralls: command not found  # Uncaught error breaks CI

# After: Installation fails silently, coverage step detects and exits cleanly
Failed to download coveralls binary or checksum (Linux).
Coveralls binary not found. Skipping coverage report.  # CI continues

Original prompt

---

This section details on the original issue you should resolve

<issue_title>fail-on-error doesn't work well when download fails</issue_title>
<issue_description>https://github.com/PowerDNS/pdns/actions/runs/19316037365/workflow?pr=16483#L116-L124

https://github.com/PowerDNS/pdns/actions/runs/19316037365/job/55247983411?pr=16483#step:12:145

github-action/action.yml

Line 68 in e988b39

fail-on-error:

Run coverallsapp/github-action@648a8eb78e6d50909eff900e4ec85cab4524a45b
```yml
  with:
    flag-name: auth-backend-remote
    path-to-lcov: $GITHUB_WORKSPACE/coverage.lcov
    parallel: true
    allow-empty: true
    fail-on-error: false
    github-token: ***
    coveralls-endpoint: https://coveralls.io/
    debug: false
    measure: false
    coverage-reporter-version: latest
    coverage-reporter-platform: auto-detect
  env:
    COMPILER: clang
    CLANG_VERSION: 13
    REPO_HOME: /__w/pdns/pdns
    BUILDER_VERSION: 0.0.0-git1
    COVERAGE: yes
    LLVM_PROFILE_FILE: /tmp/code-%p.profraw
    OPTIMIZATIONS: yes
    INV_CMD: . ${REPO_HOME}/.venv/bin/activate && inv
    BRANCH_NAME: 16483/merge
    normalized-branch-name: 16483-merge

Run # Enable debugging if 'debug' is true

github-action/action.yml

Lines 189 to 190 in e988b39

	echo "Failed to download coveralls binary or checksum (Linux)."
	[ "${{ inputs.fail-on-error }}" == "false" ] && exit 0

Failed to download coveralls binary or checksum (Linux).

github-action/action.yml

Lines 293 to 306 in e988b39

	- name: Coverage report
	if: inputs.parallel-finished != 'true'
	shell: ${{ startsWith(runner.os, 'Windows') && 'pwsh' || 'bash' }}
	run: >-
	coveralls report
	${{ inputs.debug == 'true' && '--debug' || '' }}
	${{ inputs.measure == 'true' && '--measure' || '' }}
	${{ inputs.fail-on-error == 'false' && '--no-fail' || '' }}
	${{ inputs.allow-empty == 'true' && '--allow-empty' || '' }}
	${{ inputs.base-path && format('--base-path {0}', inputs.base-path) || '' }}
	${{ inputs.build-number && format('--build-number {0}', inputs.build-number) || '' }}
	${{ inputs.format && format('--format {0}', inputs.format) || '' }}
	${{ inputs.file || inputs.path-to-lcov }}
	${{ inputs.files }}

Run coveralls report   --no-fail --allow-empty    $GITHUB_WORKSPACE/coverage.lcov 
/__w/_temp/16d91b4a-8e91-488a-abb2-9f38bdb90eed.sh: line 1: coveralls: command not found

</issue_description>

<agent_instructions>Please make sure the fail-on-error behavior wraps all actions that may potentially fail and raise an error that could break the user's CI workflow.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes fail-on-error doesn't work well when download fails #253

---

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[jsoref]

Best practices say that you should not use ${{...}} in a run: block, but instead should use env: for the value and then use that variable in the run: block.

[afinetooth]

Looks good enough to release incremental version for testing.

[afinetooth]

OK, will look at that asap.

Did you happen to test v2.3.7?

[afinetooth]

The main bug reported here has been fixed in PR #254 and will be released Release v2.3.7.

However, there's a remaining enhancement suggestion, which will be tracked in #257.

[jsoref]

We're using v2.3.7 PowerDNS/pdns@2182d55

I can't say we've particularly noticed things. There are plenty of problems with instability, but I certainly haven't noticed any problems due to the update.