GitHub Actions run step hardcodes ./build.cmd — breaks non-Windows runners (fix: pwsh build.ps1) #516

Summary

GitHubActionsRunStep.Write() emits run: ./{BuildCmdPath} <targets> for every job regardless of the runner image, and ConfigurationAttributeBase.BuildCmdPath only globs build.cmd (never build.sh/build.ps1). So any workflow generated for an Ubuntu*/MacOs* image gets ./build.cmd, which can't execute — only windows-* runners work.

Repro

[GitHubActions("ci", GitHubActionsImage.UbuntuLatest, InvokedTargets = [nameof(Foo)])]

generates:

runs-on: ubuntu-latest
...
  run: ./build.cmd Foo      # .cmd on ubuntu → fails

Cause (10.3.49)

• Fallout.Common.CI.GitHubActions.Configuration.GitHubActionsRunStep.Write → " run: ./" + BuildCmdPath + " " + JoinSpace(InvokedTargets)
• Fallout.Common.CI.ConfigurationAttributeBase.BuildCmdPath → globs build.cmd, */build.cmd only

No branch on GitHubActionsImage. Confirmed across both assemblies: zero references to build.sh or build.ps1; build.cmd is the only build-script string (2 glob literals in Fallout.Build). The build.sh/build.ps1 bootstrap files ship, but the generator only ever knows build.cmd.

Fix — pwsh route (decided)

pwsh is on every GitHub-hosted runner (win/linux/mac) and build.ps1 already takes targets positionally (ValueFromRemainingArguments), so invoke pwsh and drop per-OS script selection entirely:

1. ConfigurationAttributeBase — add a pwsh path mirroring BuildCmdPath:

   protected virtual string BuildScriptPath =>
       Build.RootDirectory.GlobFiles("build.ps1", "*/build.ps1")
           .Select(x => Build.RootDirectory.GetUnixRelativePathTo(x))
           .FirstOrDefault().NotNull();

2. GitHubActionsRunStep.Write — invoke pwsh:

   writer.WriteLine("  run: pwsh -File ./" + BuildScriptPath + " " + JoinSpace(InvokedTargets));

   (thread BuildScriptPath through the attribute's GetSteps where it currently passes BuildCmdPath.)

pwsh -File ./build.ps1 <targets> runs regardless of the runner's default shell — no shell: key, no image branch. Same swap applies to the other CI run-step writers if we want them pwsh too.

Workaround

Pin GitHubActionsImage.WindowsLatest (only image where the generated ./build.cmd runs).

Filed by AI (Claude Opus 4.8 (1M context)) on Chris's behalf.