fix(compaction): retry transient native failures

(cherry picked from commit 293c96dfa479de13995d581caec33b3c90b5b3ca)

packages/coding-agent/src/session/session-maintenance.ts

@@ -2537,16 +2537,14 @@ export class SessionMaintenance {
 							}
 
 							const message = error instanceof Error ? error.message : String(error);
-							const id = AIError.classify(error, candidate.api);
+							const id = AIError.classify(
+								error instanceof NativeCompactionError ? error.cause : error,
+								candidate.api,
+							);
 							if (AIError.is(id, AIError.Flag.AuthFailed)) {
 								lastError = this.#buildCompactionAuthError();
 								break;
 							}
-							if (error instanceof NativeCompactionError) {
-								nativeCompactionFailure ??= { error, provider: candidate.provider };
-								lastError = nativeCompactionFailure.error;
-								break;
-							}
 							if (AIError.is(id, AIError.Flag.Timeout)) {
 								logger.warn(
 									hasMoreCandidates
@@ -2569,7 +2567,12 @@ export class SessionMaintenance {
 									AIError.is(id, AIError.Flag.Transient) ||
 									AIError.is(id, AIError.Flag.UsageLimit));
 							if (!shouldRetry) {
-								lastError = error;
+								if (error instanceof NativeCompactionError) {
+									nativeCompactionFailure ??= { error, provider: candidate.provider };
+									lastError = nativeCompactionFailure.error;
+								} else {
+									lastError = error;
+								}
 								break;
 							}
 
@@ -2579,6 +2582,11 @@ export class SessionMaintenance {
 							// If retry delay is too long (>30s), try next candidate instead of waiting
 							const maxAcceptableDelayMs = 30_000;
 							if (delayMs > maxAcceptableDelayMs && hasMoreCandidates) {
+								if (error instanceof NativeCompactionError) {
+									nativeCompactionFailure ??= { error, provider: candidate.provider };
+									lastError = nativeCompactionFailure.error;
+									break;
+								}
 								logger.warn("Auto-compaction retry delay too long, trying next model", {
 									delayMs,
 									retryAfterMs,

packages/coding-agent/test/issue-986-compaction-auth-fallback.test.ts

@@ -1,7 +1,9 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "bun:test";
 import * as path from "node:path";
+import { scheduler } from "node:timers/promises";
 import { Agent } from "@oh-my-pi/pi-agent-core";
 import * as compactionModule from "@oh-my-pi/pi-agent-core/compaction";
+import * as AIError from "@oh-my-pi/pi-ai/error";
 import { getBundledModel } from "@oh-my-pi/pi-catalog/models";
 import { ModelRegistry } from "@oh-my-pi/pi-coding-agent/config/model-registry";
 import { Settings } from "@oh-my-pi/pi-coding-agent/config/settings";
@@ -188,6 +190,39 @@ describe("issue #986 compaction auth fallback", () => {
 		]);
 	});
 
+	it("retries a transient native compaction failure on the same candidate", async () => {
+		const { currentModel, triggerAutoCompaction } = await createAutoNativeFallbackSession();
+		session.settings.set("retry.enabled", true);
+		session.settings.set("retry.baseDelayMs", 1);
+		session.settings.set("retry.maxRetries", 1);
+		const waitSpy = vi.spyOn(scheduler, "wait").mockResolvedValue(undefined);
+		const attemptedModels: string[] = [];
+		vi.spyOn(compactionModule, "compact").mockImplementation(async (preparation, model) => {
+			attemptedModels.push(`${model.provider}/${model.id}`);
+			if (model.provider !== currentModel.provider || model.id !== currentModel.id) {
+				throw new Error(`Unexpected compaction model ${model.provider}/${model.id}`);
+			}
+			if (attemptedModels.length === 1) {
+				throw new compactionModule.NativeCompactionError(
+					new AIError.ProviderHttpError("native compaction temporarily unavailable", 503),
+				);
+			}
+			return {
+				summary: "native retry summary",
+				shortSummary: "native retry",
+				firstKeptEntryId: preparation.firstKeptEntryId,
+				tokensBefore: 42,
+			};
+		});
+
+		await triggerAutoCompaction();
+
+		expect(attemptedModels).toEqual([
+			`${currentModel.provider}/${currentModel.id}`,
+			`${currentModel.provider}/${currentModel.id}`,
+		]);
+		expect(waitSpy).toHaveBeenCalledTimes(1);
+	});
 	it("stops auto-compaction before a same-provider candidate with native compaction disabled", async () => {
 		const { currentModel, sameProviderModel, triggerAutoCompaction } = await createAutoNativeFallbackSession({
 			sameProviderNativeEnabled: false,