internal/rosa: store artifact results in struct

This is cleaner and makes adding additional values easier.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/all.go

@@ -256,9 +256,10 @@ var (
 	artifactsM [PresetEnd]Metadata
 
 	// artifacts stores the result of Metadata.f.
-	artifacts [_toolchainEnd][len(artifactsM)]pkg.Artifact
-	// versions stores the version of [PArtifact].
-	versions [_toolchainEnd][len(artifactsM)]string
+	artifacts [_toolchainEnd][len(artifactsM)]struct {
+		a pkg.Artifact
+		v string
+	}
 	// artifactsOnce is for lazy initialisation of artifacts.
 	artifactsOnce [_toolchainEnd][len(artifactsM)]sync.Once
 )
@@ -266,20 +267,23 @@ var (
 // GetMetadata returns [Metadata] of a [PArtifact].
 func GetMetadata(p PArtifact) *Metadata { return &artifactsM[p] }
 
+// construct constructs a [pkg.Artifact] corresponding to a [PArtifact] once.
+func (t Toolchain) construct(p PArtifact) {
+	artifactsOnce[t][p].Do(func() {
+		artifacts[t][p].a, artifacts[t][p].v = artifactsM[p].f(t)
+	})
+}
+
 // Load returns the resulting [pkg.Artifact] of [PArtifact].
 func (t Toolchain) Load(p PArtifact) pkg.Artifact {
-	artifactsOnce[t][p].Do(func() {
-		artifacts[t][p], versions[t][p] = artifactsM[p].f(t)
-	})
-	return artifacts[t][p]
+	t.construct(p)
+	return artifacts[t][p].a
 }
 
 // Version returns the version string of [PArtifact].
 func (t Toolchain) Version(p PArtifact) string {
-	artifactsOnce[t][p].Do(func() {
-		artifacts[t][p], versions[t][p] = artifactsM[p].f(t)
-	})
-	return versions[t][p]
+	t.construct(p)
+	return artifacts[t][p].v
 }
 
 // ResolveName returns a [PArtifact] by name.