refactor(chatCore): extrai resolveCompressionSettings (#3501) (#4826)

Integrated into release/v3.8.36 (#3501 chatCore extraction stack 1/13)

open-sse/handlers/chatCore.ts

@@ -165,6 +165,7 @@ import {
   restoreClaudePassthroughToolNames,
   mergeResponseToolNameMap,
 } from "./chatCore/passthroughToolNames.ts";
+import { resolveCompressionSettings } from "./chatCore/compressionSettings.ts";
 import { recordContextEditingTelemetryHook } from "./chatCore/contextEditingTelemetry.ts";
 import { recordCompressionCacheStats } from "./chatCore/compressionCacheStats.ts";
 import { writeCavemanOutputAnalytics } from "./chatCore/cavemanOutputAnalytics.ts";
@@ -875,20 +876,10 @@ export async function handleChatCore({
   let contextEditingEnabled = false;
   if (body && Array.isArray(allMessages) && allMessages.length > 0) {
     let estimatedTokens = estimateTokens(allMessages);
-    let promptCompressionEnabled = false;
-    let compressionSettings: CompressionConfig | null = null;
-
-    try {
-      const { getCompressionSettings } = await import("../../src/lib/db/compression.ts");
-      compressionSettings = await getCompressionSettings();
-      promptCompressionEnabled = compressionSettings.enabled;
-      contextEditingEnabled = compressionSettings.contextEditing?.enabled === true;
-    } catch (err) {
-      log?.warn?.(
-        "COMPRESSION",
-        "Compression settings lookup skipped: " + (err instanceof Error ? err.message : String(err))
-      );
-    }
+    const compressionSettingsResult = await resolveCompressionSettings(log);
+    const compressionSettings: CompressionConfig | null = compressionSettingsResult.settings;
+    const promptCompressionEnabled = compressionSettingsResult.enabled;
+    contextEditingEnabled = compressionSettingsResult.contextEditingEnabled;
 
     // --- Modular Compression Pipeline (Phase 1 Lite + Phase 2 Standard/Caveman + Phase 3 Aggressive) ---
     // Runs BEFORE the existing reactive compressContext() to proactively reduce tokens.

open-sse/handlers/chatCore/compressionSettings.ts

@@ -0,0 +1,35 @@
+/**
+ * chatCore compression settings resolution (Quality Gate v2 / Fase 9 — chatCore god-file
+ * decomposition, #3501).
+ *
+ * Extracted from handleChatCore's Proactive Context Compression setup: read the canonical
+ * compression settings and derive the prompt-compression and delegated context-editing flags.
+ * Best-effort — on a lookup error it logs and falls back to disabled, exactly like the previous
+ * inline try/catch. Behaviour is byte-identical.
+ */
+
+import type { CompressionConfig } from "../../services/compression/types.ts";
+
+type LoggerLike = { warn?: (...args: unknown[]) => void } | null | undefined;
+
+export async function resolveCompressionSettings(log?: LoggerLike): Promise<{
+  settings: CompressionConfig | null;
+  enabled: boolean;
+  contextEditingEnabled: boolean;
+}> {
+  try {
+    const { getCompressionSettings } = await import("@/lib/db/compression");
+    const settings = await getCompressionSettings();
+    return {
+      settings,
+      enabled: settings.enabled,
+      contextEditingEnabled: settings.contextEditing?.enabled === true,
+    };
+  } catch (err) {
+    log?.warn?.(
+      "COMPRESSION",
+      "Compression settings lookup skipped: " + (err instanceof Error ? err.message : String(err))
+    );
+    return { settings: null, enabled: false, contextEditingEnabled: false };
+  }
+}

tests/unit/chatcore-compression-settings.test.ts

@@ -0,0 +1,44 @@
+// Characterization of resolveCompressionSettings — the compression settings read extracted from
+// handleChatCore's Proactive Context Compression setup (chatCore god-file decomposition, #3501).
+// Uses a real temp DB (getCompressionSettings reads/seeds the settings row). Locks: the derived
+// enabled / contextEditingEnabled flags and the disabled fallback shape.
+import { test, before, after } from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const testDataDir = fs.mkdtempSync(path.join(os.tmpdir(), "omni-comp-settings-test-"));
+process.env.DATA_DIR = testDataDir;
+
+const coreDb = await import("../../src/lib/db/core.ts");
+const { resolveCompressionSettings } = await import(
+  "../../open-sse/handlers/chatCore/compressionSettings.ts"
+);
+
+before(async () => {
+  await coreDb.ensureDbInitialized();
+});
+
+after(() => {
+  coreDb.resetDbInstance();
+  try {
+    fs.rmSync(testDataDir, { recursive: true, force: true });
+  } catch {
+    // best-effort cleanup
+  }
+});
+
+test("returns the settings object from the DB", async () => {
+  const result = await resolveCompressionSettings();
+  assert.ok(result.settings, "expected a settings object from the seeded DB");
+});
+
+test("derives enabled and contextEditingEnabled from the settings", async () => {
+  const result = await resolveCompressionSettings();
+  // `enabled` mirrors settings.enabled exactly
+  assert.equal(result.enabled, result.settings!.enabled);
+  // `contextEditingEnabled` is the strict === true derivation of the nested flag
+  assert.equal(result.contextEditingEnabled, result.settings!.contextEditing?.enabled === true);
+  assert.equal(typeof result.contextEditingEnabled, "boolean");
+});