feat(logger): disk-backed log store for bounded CLI memory (PER-7809)

packages/core/src/api.js

@@ -230,7 +230,7 @@ export function createPercyServer(percy, port) {
       if (cmd === 'reset') {
         // the reset command will reset testing mode and clear any logs
         percy.testing = {};
-        logger.instance.messages.clear();
+        logger.instance.reset();
       } else if (cmd === 'version') {
         // the version command will update the api version header for testing
         percy.testing.version = body;
@@ -262,7 +262,7 @@ export function createPercyServer(percy, port) {
     }))
   // returns an array of raw logs from the logger
     .route('get', '/test/logs', (req, res) => res.json(200, {
-      logs: Array.from(logger.instance.messages)
+      logs: logger.instance.query(() => true)
     }))
   // serves a very basic html page for testing snapshots
     .route('get', '/test/snapshot', (req, res) => {

packages/core/src/discovery.js

@@ -217,9 +217,8 @@ function processSnapshotResources({ domSnapshot, resources, ...snapshot }) {
   resources = resources.flat();
 
   // include associated snapshot logs matched by meta information
-  resources.push(createLogResource(logger.query(log => (
-    log.meta.snapshot?.testCase === snapshot.meta.snapshot.testCase && log.meta.snapshot?.name === snapshot.meta.snapshot.name
-  ))));
+  resources.push(createLogResource(logger.snapshotLogs(snapshot.meta.snapshot)));
+  logger.evictSnapshot(snapshot.meta.snapshot);
 
   if (process.env.PERCY_GZIP) {
     for (let index = 0; index < resources.length; index++) {

packages/core/test/api.test.js

@@ -667,7 +667,7 @@ describe('API Server', () => {
     beforeEach(async () => {
       process.env.PERCY_TOKEN = 'TEST_TOKEN';
       percy = await Percy.start({ testing: true });
-      logger.instance.messages.clear();
+      logger.instance.reset();
     });
 
     afterEach(() => {

packages/core/test/helpers/index.js

@@ -23,6 +23,13 @@ export async function setupTest({
   loggerTTY,
   apiDelay
 } = {}) {
+  // Why: downstream packages (cli-exec, cli-snapshot, percy core, etc.) use
+  // mockfs as their default fs sandbox, and the disk-backed logger flakes
+  // ENOENT against mockfs's volume mid-flush — which leaks the fallback
+  // warning into another test's captured stderr. Keep these tests in
+  // unbounded in-memory mode (master parity) — the disk path has its own
+  // dedicated coverage in logger.test.js.
+  process.env.PERCY_LOGS_IN_MEMORY = '1';
   await api.mock({ delay: apiDelay });
   await logger.mock({ isTTY: loggerTTY });
   await resetPercyConfig(resetConfig);

packages/core/test/percy.test.js

@@ -1180,7 +1180,7 @@ describe('Percy', () => {
       percy.log.info('cli_test');
       percy.log.info('ci_test', {}, true);
       const logsObject = {
-        clilogs: Array.from(logger.instance.messages)
+        clilogs: logger.instance.query(() => true)
       };
 
       const content = base64encode(Pako.gzip(JSON.stringify(logsObject)));

packages/logger/src/index.js

@@ -11,6 +11,9 @@ Object.defineProperties(logger, {
   constructor: { get: () => Logger },
   instance: { get: () => new Logger() },
   query: { value: (...args) => logger.instance.query(...args) },
+  snapshotLogs: { value: (...args) => logger.instance.snapshotLogs(...args) },
+  evictSnapshot: { value: (...args) => logger.instance.evictSnapshot(...args) },
+  reset: { value: (...args) => logger.instance.reset(...args) },
   format: { value: (...args) => logger.instance.format(...args) },
   loglevel: { value: (...args) => logger.instance.loglevel(...args) },
   timeit: { get: () => new TimeIt(logger.instance.group('timer')) },