From f6d2ec7c5eeaa3dd09c3fd4543c79552127a06fe Mon Sep 17 00:00:00 2001
From: Rach Pradhan <54503978+justrach@users.noreply.github.com>
Date: Mon, 23 Mar 2026 16:20:08 +0800
Subject: [PATCH] fix hot cache OOM cleanup on insert

Add errdefer cleanup for pool-created LRU entries before map.put and cover the failure path with checkAllAllocationFailures.

Refs #223
---
 src/graph/hot_cache.zig | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/graph/hot_cache.zig b/src/graph/hot_cache.zig
index 310fc75..49f471b 100644
--- a/src/graph/hot_cache.zig
+++ b/src/graph/hot_cache.zig
@@ -72,6 +72,7 @@ pub fn LruCache(comptime V: type) type {
 
             // Insert new entry
             const entry = try self.pool.create();
+            errdefer self.pool.destroy(entry);
             entry.* = .{ .key = key, .value = value };
             try self.map.put(key, entry);
             self.pushFront(entry);
@@ -156,6 +157,13 @@ pub const CachedSymbol = struct {
     line: u32,
 };
 
+fn hotCachePutNoLeakOnFailure(allocator: std.mem.Allocator) !void {
+    var cache = LruCache(u32).init(allocator, 4);
+    defer cache.deinit();
+
+    try cache.put(1, 100);
+}
+
 // ── Tests ───────────────────────────────────────────────────────────────────
 
 test "basic put and get" {
@@ -218,6 +226,10 @@ test "put updates existing key" {
     try std.testing.expectEqual(@as(?u32, 200), cache.get(1));
 }
 
+test "put cleans up pool entry when map.put fails" {
+    try std.testing.checkAllAllocationFailures(std.testing.allocator, hotCachePutNoLeakOnFailure, .{});
+}
+
 test "remove deletes entry" {
     var cache = LruCache(u32).init(std.testing.allocator, 4);
     defer cache.deinit();