Fix Go runtime setup failure when go.mod doesn't exist

[Copilot]

• Updated DefaultGoVersion constant from 1.23 to 1.25
• Updated unit tests to expect version 1.25
• Updated integration tests to expect version 1.25
• Recompiled workflow lock files with new Go version
• All tests passing

Original prompt

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This section details on the original issue you should resolve

<issue_title>Bug: Go runtime setup fails when go.mod doesn't exist</issue_title>
<issue_description>## Problem

The compiler automatically adds a "Setup Go" step when it detects Go commands (e.g., go version in custom steps or Serena Go language service), but this step fails if the repository doesn't have a go.mod file.

Root Cause

In pkg/workflow/runtime_setup.go:

1. Go runtime definition (lines 77-84):

   {
   ID: "go",
   Name: "Go",
   ActionRepo: "actions/setup-go",
   ActionVersion: "v5",
   VersionField: "go-version",
   DefaultVersion: "", // Special handling: uses go.modCommands: []string{"go"},
   }

2. Setup step generation (lines 575-583):

   ifruntime.ID=="go"&& (version==""||req.GoModFile!="") {
   step=append(step, " with:")
   goModPath:="go.mod"// ⚠️ Assumes go.mod existsifreq.GoModFile!="" {
   goModPath=req.GoModFile
   }
   step=append(step, fmt.Sprintf(" go-version-file: %s", goModPath))
   step=append(step, " cache: true")
   // ...
   }

Result: The generated workflow uses go-version-file: go.mod, which fails if the file doesn't exist:

Error: The specified go version file at: go.mod does not exist

Steps to Reproduce

1. Create a workflow that uses Claude with Serena Go language service or has a custom step with go version
2. Run it in a repository without a go.mod file
3. The workflow fails during the "Setup Go" step

Proposed Fix

Add a default Go version and use it as a fallback:

1. Add to pkg/constants/constants.go:

   // DefaultGoVersion is the default version of Go for runtime setupconstDefaultGoVersionVersion="1.23"

2. Update pkg/workflow/runtime_setup.go:82:

   DefaultVersion: string(constants.DefaultGoVersion),

3. Update logic at runtime_setup.go:575 to only use go-version-file when explicitly specified:

   ifruntime.ID=="go"&&req.GoModFile!="" {
   // Only use go-version-file if explicitly specifiedstep=append(step, " with:")
   step=append(step, fmt.Sprintf(" go-version-file: %s", req.GoModFile))
   step=append(step, " cache: true")
   } elseifversion!="" {
   // Use explicit versionstep=append(step, " with:")
   step=append(step, fmt.Sprintf(" go-version: '%s'", version))
   }

This way:

• Repos withgo.mod can explicitly specify go-mod-file in frontmatter
• Repos withoutgo.mod will use the default Go version
• Users can still override with explicit version in frontmatter

Related Code

• Detection:pkg/workflow/compiler_yaml.go:246 calls DetectRuntimeRequirements()
• Generation:pkg/workflow/compiler_yaml.go:263 calls GenerateRuntimeSetupSteps()
• Runtime setup:pkg/workflow/runtime_setup.go:169-224 (detection) and pkg/workflow/runtime_setup.go:443-453 (generation)</issue_description>

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

• FixesBug: Go runtime setup fails when go.mod doesn't exist #5582

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[pelikhan]

@copilot Default version 1.25

[Copilot]

@copilot Default version 1.25

Updated default Go version to 1.25 in commit be83d9a

[pelikhan]

@copilot recompile

[Copilot]

@copilot recompile

Recompiled workflow lock files in commit 90877a3. Updated 15 lock files with Go version 1.25.