Release validation source bytes after checks

internal/validation/validation.go

@@ -199,6 +199,7 @@ func checkWorkspaceFiles(tree *CandidateTree) error {
 
 func checkGoFormat(ctx context.Context, tree *CandidateTree) error {
 	var findings []Finding
+	formattedByObjectID := make(map[string]bool)
 	for _, entry := range tree.Entries() {
 		if entry.Type != "blob" || (entry.Mode != "100644" && entry.Mode != "100755") || !strings.HasSuffix(entry.Path, ".go") {
 			continue
@@ -206,6 +207,12 @@ func checkGoFormat(ctx context.Context, tree *CandidateTree) error {
 		if err := ctx.Err(); err != nil {
 			return &Failure{Check: GoFormat, Cause: err}
 		}
+		if formatted, ok := formattedByObjectID[entry.ObjectID]; ok {
+			if !formatted {
+				findings = append(findings, Finding{Path: entry.Path, Message: "file is not gofmt-formatted"})
+			}
+			continue
+		}
 		contents, err := tree.ReadFile(ctx, entry.Path)
 		if err != nil {
 			return &Failure{
@@ -228,7 +235,11 @@ func checkGoFormat(ctx context.Context, tree *CandidateTree) error {
 				Cause: fmt.Errorf("format committed Go file %q: %w", entry.Path, err),
 			}
 		}
-		if !bytes.Equal(contents, formatted) {
+		isFormatted := bytes.Equal(contents, formatted)
+		formattedByObjectID[entry.ObjectID] = isFormatted
+		contents = nil
+		formatted = nil
+		if !isFormatted {
 			findings = append(findings, Finding{Path: entry.Path, Message: "file is not gofmt-formatted"})
 		}
 	}