Summary

When a directory named GEMINI.md exists anywhere in the workspace tree, memory discovery currently surfaces a confusing Could not read GEMINI.md warning because fs.readFile throws EISDIR on directories. Directories with that name are valid in some project structures and should simply be ignored.

This PR detects EISDIR specifically in the readGeminiMdFiles catch block and skips silently with a debug log, while preserving the warning behaviour for genuinely unexpected read errors.

Fixes #16282

Implementation

packages/core/src/utils/memoryDiscovery.ts — extend the existing catch block:

const isEISDIR =
  error instanceof Error &&
  (error as NodeJS.ErrnoException).code === 'EISDIR';

if (isEISDIR) {
  // Skip silently — a directory at this path is a legitimate case.
  debugLogger.debug('[DEBUG] [MemoryDiscovery] Skipping directory at GEMINI.md path:', filePath);
} else {
  // ... existing warn behaviour ...
}

The return value is unchanged ({ filePath, content: null }) so downstream consumers continue to see the same shape.

Tests

Two new tests in memoryDiscovery.test.ts:

1. Direct unit test — readGeminiMdFiles returns { content: null } (without throwing) when given a directory path
2. End-to-end test — loadServerHierarchicalMemory returns empty memory when a GEMINI.md directory exists in the workspace

Test results:

✓ packages/core/src/utils/memoryDiscovery.test.ts (44 tests) 107ms
Test Files  1 passed (1)
     Tests  44 passed (44)

tsc --noEmit and eslint both pass with zero output.

Relationship to #22852

This supersedes #22852 (closed 2026-04-09 due to test failures and 23 days of inactivity). Credit to @shathwik30 for the original work; the production-code shape here uses the same NodeJS.ErrnoException type guard that @gemini-code-assist suggested on that PR.

What's different in this PR:

• Tests are written from scratch against the current memoryDiscovery.ts and verified to pass locally before submission
• Added a direct readGeminiMdFiles unit test (alongside the e2e test) to keep the failure surface narrow and easy to debug for future contributors
• The end-to-end test asserts only memoryContent === '', which is the user-visible contract the issue actually cares about, rather than relying on fileCount semantics that could shift