From 8f840a6b7fe489b63353e36f9d875d0b874d2059 Mon Sep 17 00:00:00 2001
From: tt-a1i <53142663+tt-a1i@users.noreply.github.com>
Date: Mon, 22 Jun 2026 20:59:45 +0800
Subject: [PATCH] fix(core): require integer compaction counts

---
 .../services/compactionInputSlimming.test.ts  | 63 +++++++++++++++++++
 .../src/services/compactionInputSlimming.ts   | 37 +++++++----
 2 files changed, 87 insertions(+), 13 deletions(-)

diff --git a/packages/core/src/services/compactionInputSlimming.test.ts b/packages/core/src/services/compactionInputSlimming.test.ts
index 678e47aa650..a91c5741430 100644
--- a/packages/core/src/services/compactionInputSlimming.test.ts
+++ b/packages/core/src/services/compactionInputSlimming.test.ts
@@ -123,6 +123,69 @@ describe('compactionInputSlimming', () => {
       expect(t.screenshotTriggerThreshold).toBe(99);
     });
 
+    it('rejects fractional count-like env values', () => {
+      const cases = [
+        {
+          envKey: 'QWEN_COMPACT_MAX_RECENT_FILES',
+          value: '1.5',
+          settings: { maxRecentFilesToRetain: 4 },
+          get: (t: ReturnType<typeof resolveCompactionTuning>) =>
+            t.maxRecentFiles,
+          expected: 4,
+        },
+        {
+          envKey: 'QWEN_COMPACT_MAX_RECENT_IMAGES',
+          value: '2.5',
+          settings: { maxRecentImagesToRetain: 5 },
+          get: (t: ReturnType<typeof resolveCompactionTuning>) =>
+            t.maxRecentImages,
+          expected: 5,
+        },
+        {
+          envKey: 'QWEN_COMPACT_SCREENSHOT_THRESHOLD',
+          value: '9007199254740990.5',
+          settings: { screenshotTriggerThreshold: 6 },
+          get: (t: ReturnType<typeof resolveCompactionTuning>) =>
+            t.screenshotTriggerThreshold,
+          expected: 6,
+        },
+      ] as const;
+
+      for (const c of cases) {
+        for (const k of COMPACTION_ENV_KEYS) delete process.env[k];
+        process.env[c.envKey] = c.value;
+        expect(c.get(resolveCompactionTuning(c.settings))).toBe(c.expected);
+      }
+    });
+
+    it('rejects fractional count-like settings values', () => {
+      const t = resolveCompactionTuning({
+        maxRecentFilesToRetain: 1.5,
+        maxRecentImagesToRetain: 2.5,
+        screenshotTriggerThreshold: 3.5,
+      });
+      expect(t.maxRecentFiles).toBe(DEFAULT_MAX_RECENT_FILES);
+      expect(t.maxRecentImages).toBe(DEFAULT_MAX_RECENT_IMAGES);
+      expect(t.screenshotTriggerThreshold).toBe(
+        DEFAULT_SCREENSHOT_TRIGGER_THRESHOLD,
+      );
+    });
+
+    it('rejects unsafe integer count-like values', () => {
+      process.env['QWEN_COMPACT_MAX_RECENT_FILES'] = String(
+        Number.MAX_SAFE_INTEGER + 1,
+      );
+      const envFallback = resolveCompactionTuning({
+        maxRecentFilesToRetain: 4,
+      });
+      expect(envFallback.maxRecentFiles).toBe(4);
+
+      const settingsFallback = resolveCompactionTuning({
+        maxRecentImagesToRetain: Number.MAX_SAFE_INTEGER + 1,
+      });
+      expect(settingsFallback.maxRecentImages).toBe(DEFAULT_MAX_RECENT_IMAGES);
+    });
+
     it('parses the boolean env both ways and ignores typos', () => {
       process.env['QWEN_COMPACT_SCREENSHOT_TRIGGER'] = 'false';
       expect(resolveCompactionTuning(undefined).enableScreenshotTrigger).toBe(
diff --git a/packages/core/src/services/compactionInputSlimming.ts b/packages/core/src/services/compactionInputSlimming.ts
index 17ae2284cca..52b44098e9d 100644
--- a/packages/core/src/services/compactionInputSlimming.ts
+++ b/packages/core/src/services/compactionInputSlimming.ts
@@ -80,19 +80,29 @@ function resolveNumber(
   envValue: string | undefined,
   settingsValue: number | undefined,
   defaultValue: number,
-  { minInclusive }: { minInclusive: number },
+  {
+    integer = false,
+    minInclusive,
+  }: { integer?: boolean; minInclusive: number },
 ): number {
+  const isValid = (value: number) =>
+    Number.isFinite(value) &&
+    (!integer || Number.isSafeInteger(value)) &&
+    value >= minInclusive;
+
   if (envValue !== undefined && envValue !== '') {
-    const parsed = Number(envValue);
-    if (Number.isFinite(parsed) && parsed >= minInclusive) {
+    const trimmed = envValue.trim();
+    if (integer && !/^\d+$/.test(trimmed)) {
+      return settingsValue !== undefined && isValid(settingsValue)
+        ? settingsValue
+        : defaultValue;
+    }
+    const parsed = Number(trimmed);
+    if (isValid(parsed)) {
       return parsed;
     }
   }
-  if (
-    settingsValue !== undefined &&
-    Number.isFinite(settingsValue) &&
-    settingsValue >= minInclusive
-  ) {
+  if (settingsValue !== undefined && isValid(settingsValue)) {
     return settingsValue;
   }
   return defaultValue;
@@ -116,8 +126,9 @@ export interface ResolvedCompactionTuning {
 
 /**
  * Resolves the post-compact retention + screenshot-trigger knobs in
- * priority order env > settings > default, reusing the same validation
- * rules as `resolveSlimmingConfig`.
+ * priority order env > settings > default. Count-like fields require
+ * integer values because downstream collectors compare against integer
+ * lengths.
  *
  * The screenshot trigger counts only images nested in
  * `functionResponse.parts` (tool results). Compaction replaces those with
@@ -134,13 +145,13 @@ export function resolveCompactionTuning(
       process.env['QWEN_COMPACT_MAX_RECENT_FILES'],
       settings?.maxRecentFilesToRetain,
       DEFAULT_MAX_RECENT_FILES,
-      { minInclusive: 0 },
+      { integer: true, minInclusive: 0 },
     ),
     maxRecentImages: resolveNumber(
       process.env['QWEN_COMPACT_MAX_RECENT_IMAGES'],
       settings?.maxRecentImagesToRetain,
       DEFAULT_MAX_RECENT_IMAGES,
-      { minInclusive: 0 },
+      { integer: true, minInclusive: 0 },
     ),
     enableScreenshotTrigger: resolveBoolean(
       process.env['QWEN_COMPACT_SCREENSHOT_TRIGGER'],
@@ -151,7 +162,7 @@ export function resolveCompactionTuning(
       process.env['QWEN_COMPACT_SCREENSHOT_THRESHOLD'],
       settings?.screenshotTriggerThreshold,
       DEFAULT_SCREENSHOT_TRIGGER_THRESHOLD,
-      { minInclusive: 1 },
+      { integer: true, minInclusive: 1 },
     ),
   };
 }