Fixed a redundant path bug for previous session artifacts

internal/artifacts/paths.go

@@ -2,6 +2,7 @@ package artifacts
 
 import (
 	"path/filepath"
+	"strings"
 
 	"gitea.maximumdirect.net/eric/narratio/internal/config"
 )
@@ -64,7 +65,7 @@ func SessionPreviousArtifactsDirForCampaign(rootDir, campaign, sessionID string)
 func SessionPreviousArtifactPathForCampaign(rootDir, campaign, sessionID, artifactRelativePath string) string {
 	return filepath.Join(
 		SessionPreviousArtifactsDirForCampaign(rootDir, campaign, sessionID),
-		filepath.FromSlash(artifactRelativePath),
+		filepath.FromSlash(previousArtifactCacheRelativePath(artifactRelativePath)),
 	)
 }
 
@@ -105,7 +106,19 @@ func SessionPreviousArtifactsDir(paths SessionPaths) string {
 
 // SessionPreviousArtifactPath returns a path under previous/artifacts for already-resolved session paths.
 func SessionPreviousArtifactPath(paths SessionPaths, artifactRelativePath string) string {
-	return filepath.Join(paths.PreviousArtifactsDir, filepath.FromSlash(artifactRelativePath))
+	return filepath.Join(paths.PreviousArtifactsDir, filepath.FromSlash(previousArtifactCacheRelativePath(artifactRelativePath)))
+}
+
+func previousArtifactCacheRelativePath(artifactRelativePath string) string {
+	rel := filepath.ToSlash(filepath.Clean(filepath.FromSlash(strings.TrimSpace(artifactRelativePath))))
+	if rel == "." {
+		return ""
+	}
+	const artifactsPrefix = "artifacts/"
+	if strings.HasPrefix(rel, artifactsPrefix) && len(rel) > len(artifactsPrefix) {
+		return strings.TrimPrefix(rel, artifactsPrefix)
+	}
+	return rel
 }
 
 func buildSessionPaths(workspaceRoot, campaign, sessionID string) SessionPaths {