esync

commit 3290272c523f71239e030be9e15a7732264381bd
parent 681a0ad0de494ad4672acbf9019395131b04d73d
Author: Erik Loualiche <eloualic@umn.edu>
Date:   Sun, 22 Mar 2026 10:13:45 -0500

feat: add findBrokenSymlinks helper for detecting dangling symlinks

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Diffstat:
M
internal/watcher/watcher.go
 | 
37
+++++++++++++++++++++++++++++++++++++
M
internal/watcher/watcher_test.go
 | 
30
++++++++++++++++++++++++++++++

2 files changed, 67 insertions(+), 0 deletions(-)
diff --git a/internal/watcher/watcher.go b/internal/watcher/watcher.go
@@ -13,6 +13,43 @@ import (
 )
 
 // ---------------------------------------------------------------------------
+// BrokenSymlink
+// ---------------------------------------------------------------------------
+
+// BrokenSymlink records a symlink whose target does not exist.
+type BrokenSymlink struct {
+	Path   string // absolute path to the symlink
+	Target string // what the symlink points to
+}
+
+// findBrokenSymlinks scans a directory for symlinks whose targets do not exist.
+func findBrokenSymlinks(dir string) []BrokenSymlink {
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return nil
+	}
+	var broken []BrokenSymlink
+	for _, e := range entries {
+		if e.Type()&os.ModeSymlink == 0 {
+			continue
+		}
+		full := filepath.Join(dir, e.Name())
+		target, err := os.Readlink(full)
+		if err != nil {
+			continue
+		}
+		// Resolve relative targets against the directory
+		if !filepath.IsAbs(target) {
+			target = filepath.Join(dir, target)
+		}
+		if _, err := os.Stat(target); err != nil {
+			broken = append(broken, BrokenSymlink{Path: full, Target: target})
+		}
+	}
+	return broken
+}
+
+// ---------------------------------------------------------------------------
 // EventHandler
 // ---------------------------------------------------------------------------
 
diff --git a/internal/watcher/watcher_test.go b/internal/watcher/watcher_test.go
@@ -1,6 +1,8 @@
 package watcher
 
 import (
+	"os"
+	"path/filepath"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -165,3 +167,31 @@ func TestShouldIncludeEmptyMeansAll(t *testing.T) {
 		}
 	}
 }
+
+// ---------------------------------------------------------------------------
+// 7. TestFindBrokenSymlinks — detects broken symlinks in a directory
+// ---------------------------------------------------------------------------
+func TestFindBrokenSymlinks(t *testing.T) {
+	dir := t.TempDir()
+
+	// Create a valid file
+	os.WriteFile(filepath.Join(dir, "good.txt"), []byte("ok"), 0644)
+
+	// Create a broken symlink
+	os.Symlink("/nonexistent/target", filepath.Join(dir, "bad.txt"))
+
+	// Create a valid symlink
+	os.Symlink(filepath.Join(dir, "good.txt"), filepath.Join(dir, "also-good.txt"))
+
+	broken := findBrokenSymlinks(dir)
+
+	if len(broken) != 1 {
+		t.Fatalf("findBrokenSymlinks found %d, want 1", len(broken))
+	}
+	if broken[0].Target != "/nonexistent/target" {
+		t.Errorf("target = %q, want %q", broken[0].Target, "/nonexistent/target")
+	}
+	if filepath.Base(broken[0].Path) != "bad.txt" {
+		t.Errorf("path base = %q, want %q", filepath.Base(broken[0].Path), "bad.txt")
+	}
+}