From 07235c0bfdcf3808e0ed4f58890beaff120b6d2b Mon Sep 17 00:00:00 2001
From: Rach Pradhan <54503978+justrach@users.noreply.github.com>
Date: Mon, 23 Mar 2026 16:22:39 +0800
Subject: [PATCH] fix watcher created events after debounce

Track the pending change kind across the debounce window so newly created files emit .created instead of collapsing to .modified. Add assertions in the creation tests.

Refs #224
---
 src/graph/watcher.zig | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/graph/watcher.zig b/src/graph/watcher.zig
index 4ebf78b..4bc66e5 100644
--- a/src/graph/watcher.zig
+++ b/src/graph/watcher.zig
@@ -41,6 +41,7 @@ const WatchEntry = struct {
     exists: bool,
     last_change_ms: i64, // for debouncing
     pending: bool, // change detected but not yet reported (debounce)
+    pending_kind: ?ChangeKind,
 };
 
 // ── FileWatcher ─────────────────────────────────────────────────────────────
@@ -82,6 +83,7 @@ pub const FileWatcher = struct {
             .exists = stat != null,
             .last_change_ms = 0,
             .pending = false,
+            .pending_kind = null,
         });
     }
 
@@ -126,12 +128,14 @@ pub const FileWatcher = struct {
                     entry.last_size = s.size;
                     entry.last_change_ms = now_ms;
                     entry.pending = true;
+                    entry.pending_kind = .created;
                 } else if (s.mtime != entry.last_modified_ns or s.size != entry.last_size) {
                     // File modified
                     entry.last_modified_ns = s.mtime;
                     entry.last_size = s.size;
                     entry.last_change_ms = now_ms;
                     entry.pending = true;
+                    entry.pending_kind = .modified;
                 }
             } else {
                 if (entry.exists) {
@@ -141,17 +145,14 @@ pub const FileWatcher = struct {
                     entry.last_size = 0;
                     entry.last_change_ms = now_ms;
                     entry.pending = true;
+                    entry.pending_kind = .deleted;
                 }
             }
 
             // Emit if pending and debounce window passed
             if (entry.pending and (now_ms - entry.last_change_ms) >= self.debounce_ms) {
-                const kind: ChangeKind = if (!entry.exists)
-                    .deleted
-                else if (entry.last_modified_ns == 0)
-                    .created
-                else
-                    .modified;
+                const fallback_kind: ChangeKind = if (!entry.exists) .deleted else .modified;
+                const kind: ChangeKind = entry.pending_kind orelse fallback_kind;
 
                 try events.append(self.alloc, .{
                     .path = entry.path,
@@ -159,6 +160,7 @@ pub const FileWatcher = struct {
                     .timestamp_ms = now_ms,
                 });
                 entry.pending = false;
+                entry.pending_kind = null;
             }
         }
 
@@ -296,6 +298,7 @@ test "poll detects new file creation" {
     const events3 = try fw.pollAt(1500);
     defer std.testing.allocator.free(events3);
     try std.testing.expectEqual(@as(usize, 1), events3.len);
+    try std.testing.expectEqual(ChangeKind.created, events3[0].kind);
 }
 
 // ── Edge case tests ─────────────────────────────────────────────────────────
@@ -399,4 +402,5 @@ test "debounce window prevents immediate reporting" {
     const events3 = try fw.pollAt(5300);
     defer std.testing.allocator.free(events3);
     try std.testing.expectEqual(@as(usize, 1), events3.len);
+    try std.testing.expectEqual(ChangeKind.created, events3[0].kind);
 }