Inspect committed module replacements

internal/validation/local_replacements.go

@@ -0,0 +1,92 @@
+package validation
+
+import (
+	"context"
+	"fmt"
+	"path"
+
+	"gitea.maximumdirect.net/eric/ReleaseKit/internal/git"
+	"golang.org/x/mod/modfile"
+)
+
+func checkLocalReplacements(ctx context.Context, tree *CandidateTree) error {
+	var findings []Finding
+	for _, entry := range tree.Entries() {
+		if path.Base(entry.Path) != "go.mod" {
+			continue
+		}
+
+		contents, err := readModuleDeclaration(ctx, tree, entry)
+		if err != nil {
+			return &Failure{
+				Check:    LocalReplacements,
+				Findings: []Finding{{Path: entry.Path, Message: "could not inspect committed module declaration"}},
+				Cause:    fmt.Errorf("inspect committed %s: %w", entry.Path, err),
+			}
+		}
+		moduleFile, err := modfile.Parse(entry.Path, contents, nil)
+		if err != nil {
+			return &Failure{
+				Check:    LocalReplacements,
+				Findings: []Finding{{Path: entry.Path, Message: "could not parse committed module declaration"}},
+				Cause:    fmt.Errorf("parse committed %s: %w", entry.Path, err),
+			}
+		}
+		for _, replacement := range moduleFile.Replace {
+			if replacement.New.Version != "" {
+				continue
+			}
+			finding := Finding{
+				Path:      entry.Path,
+				Message:   "filesystem module replacement is committed",
+				Target:    replacement.New.Path,
+				Directive: "replace",
+			}
+			if replacement.Syntax != nil {
+				finding.Line = replacement.Syntax.Start.Line
+			}
+			findings = append(findings, finding)
+		}
+	}
+	if len(findings) != 0 {
+		return &Failure{Check: LocalReplacements, Findings: findings}
+	}
+	return nil
+}
+
+func readModuleDeclaration(ctx context.Context, tree *CandidateTree, entry git.TreeEntry) ([]byte, error) {
+	if entry.Type != "blob" {
+		return nil, fmt.Errorf("entry has type %q, not a blob", entry.Type)
+	}
+	if entry.Mode != "120000" {
+		if entry.Mode != "100644" && entry.Mode != "100755" {
+			return nil, fmt.Errorf("entry has unsupported mode %q", entry.Mode)
+		}
+		contents, err := tree.ReadFile(ctx, entry.Path)
+		if err != nil {
+			return nil, fmt.Errorf("read module declaration: %w", err)
+		}
+		return contents, nil
+	}
+
+	target, err := tree.ReadFile(ctx, entry.Path)
+	if err != nil {
+		return nil, fmt.Errorf("read symlink declaration: %w", err)
+	}
+	destination, err := tree.ResolveDestination(ctx, entry.Path, string(target))
+	if err != nil {
+		return nil, fmt.Errorf("resolve symlink declaration target %q: %w", target, err)
+	}
+	if destination.Kind != DestinationEntry {
+		return nil, fmt.Errorf("symlink declaration target %q resolves to %s", target, destination.Kind)
+	}
+	resolved, ok := tree.Entry(destination.Path)
+	if !ok || resolved.Type != "blob" || (resolved.Mode != "100644" && resolved.Mode != "100755") {
+		return nil, fmt.Errorf("symlink declaration target %q does not resolve to a regular committed file", target)
+	}
+	contents, err := tree.ReadFile(ctx, destination.Path)
+	if err != nil {
+		return nil, fmt.Errorf("read resolved module declaration %q: %w", destination.Path, err)
+	}
+	return contents, nil
+}