Fix segmentation fault in dry-run mode with service containers

[TheFynx]

Description

Fixes segmentation fault that occurs when running act -n (dry-run mode) with GitHub Actions workflows containing service containers.

Fixes #2607

Problem

When running workflows with service containers in dry-run mode, Act would crash with a segmentation fault at pkg/container/docker_run.go:173 in the GetHealth() method. This happened because:

1. In dry-run mode, service containers are not actually created (no Docker client connection)
2. The health checking code still attempted to inspect non-existent containers via cr.cli.ContainerInspect(ctx, cr.id)
3. This resulted in a nil pointer dereference when cr.cli was nil

Solution

Added dry-run mode protection at two critical points:

1. GetHealth() method - Returns HealthHealthy immediately in dry-run mode instead of attempting Docker inspection
2. waitForServiceContainer() function - Skips all health checking in dry-run mode

The fix ensures that act's dry-run mode works consistently with service containers by providing appropriate mock responses instead of attempting real Docker operations.

Testing

• Added regression test TestServiceContainerWorkflowDryRun to prevent future regressions
• Manually validated that act -n with service containers no longer crashes
• All existing service container tests continue to pass:
  • TestRunEvent/services
  • TestRunEvent/services-empty-image
  • TestRunEvent/services-host-network
  • TestRunEvent/services-with-container
  • TestRunEvent/mysql-service-container-with-health-check

Compliance

• Code formatted with go fmt ./...
• Ran go mod tidy (why go.mod was altered)
• Includes test coverage of change

[ChristopherHX]

I would have added an integration test for dryrun in this list

act/pkg/runner/runner_test.go

Line 625 in 5319acf

{workdir, "local-action-js", "push", "", platforms, secrets},

Possibly just copying these lines below into the dryrun test above would resolve my concerns

act/pkg/runner/runner_test.go

Lines 325 to 329 in 5319acf

	{workdir, "services", "push", "", platforms, secrets},
	{workdir, "services-empty-image", "push", "", platforms, secrets},
	{workdir, "services-host-network", "push", "", platforms, secrets},
	{workdir, "services-with-container", "push", "", platforms, secrets},
	{workdir, "mysql-service-container-with-health-check", "push", "", platforms, secrets},

As far as I understand your (very likely via help of an AI agent generated) test especially tests the method I have introduced does work for dryrun. However this does not prevent me from breaking service container in dryrun again, like chainging the methods I call in setupjobconatiner.

Yes I almost always forget that dryrun even exists, so it is possible this feature is entire unmaintained for much longer period of time than would be healthy for this feature

[TheFynx]

Thanks for the review! I will try to circle back to this, this weekend. I'll get the changes sorted and tested.

[codecov]

Codecov Report

❌ Patch coverage is 63.63636% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.76%. Comparing base (bd4bc99) to head (d704c91).
⚠️ Report is 18 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/container/docker_run.go	46.66%	6 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5782      +/-   ##
==========================================
+ Coverage   74.65%   74.76%   +0.10%     
==========================================
  Files          73       73              
  Lines       11139    11211      +72     
==========================================
+ Hits         8316     8382      +66     
- Misses       2186     2191       +5     
- Partials      637      638       +1     

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