fix(build): emit artifact metadata from GitHub env

Co-Authored-By: Virgil <virgil@lethean.io>

cmd/build/cmd_project.go

@@ -312,6 +312,9 @@ func selectOutputArtifacts(rawArtifacts, archivedArtifacts, checksummedArtifacts
 // writeArtifactMetadata writes artifact_meta.json files next to built artifacts when CI metadata is available.
 func writeArtifactMetadata(filesystem io.Medium, buildName string, artifacts []build.Artifact) error {
 	ci := build.DetectCI()
+	if ci == nil {
+		ci = build.DetectGitHubMetadata()
+	}
 	if ci == nil {
 		return nil
 	}

pkg/build/ci.go

@@ -79,7 +79,20 @@ func FormatGitHubAnnotation(level, file string, line int, message string) string
 //	    // upload release assets
 //	}
 func DetectCI() *CIContext {
-	if core.Env("GITHUB_ACTIONS") == "" {
+	return detectGitHubContext(true)
+}
+
+// DetectGitHubMetadata returns GitHub CI metadata when the standard environment
+// variables are present, even if GITHUB_ACTIONS is unset.
+//
+// This is useful for metadata emission paths that only need the GitHub ref/SHA
+// shape and should not be coupled to a specific runner environment.
+func DetectGitHubMetadata() *CIContext {
+	return detectGitHubContext(false)
+}
+
+func detectGitHubContext(requireActions bool) *CIContext {
+	if requireActions && core.Env("GITHUB_ACTIONS") == "" {
 		return nil
 	}
 
@@ -97,17 +110,26 @@ func DetectCI() *CIContext {
 		Repo: repo,
 	}
 
+	populateGitHubContext(ctx)
+	return ctx
+}
+
+func populateGitHubContext(ctx *CIContext) {
+	if ctx == nil {
+		return
+	}
+
 	// ShortSHA is first 7 chars of SHA.
-	runes := []rune(sha)
+	runes := []rune(ctx.SHA)
 	if len(runes) >= 7 {
 		ctx.ShortSHA = string(runes[:7])
 	} else {
-		ctx.ShortSHA = sha
+		ctx.ShortSHA = ctx.SHA
 	}
 
 	// Derive owner from "owner/repo" format.
-	if repo != "" {
-		parts := core.SplitN(repo, "/", 2)
+	if ctx.Repo != "" {
+		parts := core.SplitN(ctx.Repo, "/", 2)
 		if len(parts) == 2 {
 			ctx.Owner = parts[0]
 		}
@@ -117,14 +139,12 @@ func DetectCI() *CIContext {
 	const tagPrefix = "refs/tags/"
 	const branchPrefix = "refs/heads/"
 
-	if core.HasPrefix(ref, tagPrefix) {
+	if core.HasPrefix(ctx.Ref, tagPrefix) {
 		ctx.IsTag = true
-		ctx.Tag = core.TrimPrefix(ref, tagPrefix)
-	} else if core.HasPrefix(ref, branchPrefix) {
-		ctx.Branch = core.TrimPrefix(ref, branchPrefix)
+		ctx.Tag = core.TrimPrefix(ctx.Ref, tagPrefix)
+	} else if core.HasPrefix(ctx.Ref, branchPrefix) {
+		ctx.Branch = core.TrimPrefix(ctx.Ref, branchPrefix)
 	}
-
-	return ctx
 }
 
 // ArtifactName generates a canonical artifact filename from the build name, CI context, and target.

pkg/build/ci_test.go

@@ -146,6 +146,22 @@ func TestCi_DetectCI_Bad(t *testing.T) {
 	})
 }
 
+func TestCi_DetectGitHubMetadata_Good(t *testing.T) {
+	t.Run("detects GitHub metadata without GITHUB_ACTIONS", func(t *testing.T) {
+		t.Setenv("GITHUB_ACTIONS", "")
+		t.Setenv("GITHUB_SHA", "abc1234def5678901234567890123456789012345")
+		t.Setenv("GITHUB_REF", "refs/heads/main")
+		t.Setenv("GITHUB_REPOSITORY", "org/repo")
+
+		ci := DetectGitHubMetadata()
+		require.NotNil(t, ci)
+		assert.Equal(t, "abc1234", ci.ShortSHA)
+		assert.Equal(t, "main", ci.Branch)
+		assert.Equal(t, "org/repo", ci.Repo)
+		assert.Equal(t, "org", ci.Owner)
+	})
+}
+
 func TestCi_DetectCI_Ugly(t *testing.T) {
 	t.Run("SHA shorter than 7 chars still works", func(t *testing.T) {
 		setenvCI(t, "abc", "refs/heads/main", "org/repo")