From 119094201cbd36f4508ca09f30b73142cef748cd Mon Sep 17 00:00:00 2001
From: EMRG Evolution <emrg@argszero.dev>
Date: Wed, 12 Aug 2026 19:26:16 +0800
Subject: [PATCH] emrg: write install-info cache once per process in
 resolve_git_gh

---
 Agent.md                 |  2 +-
 emrg/server/git_utils.py | 14 +++++++++++++-
 tests/test_git_utils.py  | 24 ++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/Agent.md b/Agent.md
index 53271c70..25cffee1 100644
--- a/Agent.md
+++ b/Agent.md
@@ -118,7 +118,7 @@ Community needs voiced in HN agent-UI discussions map directly to EMRG's design:
 pkill -f "emrg.server"; rm -f ~/.emrg/emrgd.port; python -m emrg
 ```
 
-Python: `uv run pytest tests/ -v` (746) — import check: `uv run python -c "from emrg.client.app import run_client"`
+Python: `uv run pytest tests/ -v` (747) — import check: `uv run python -c "from emrg.client.app import run_client"`
 GUI: `cd emrg/gui && npm test` (229: 44 daemon_client + 19 conn-manager + 22 app-commands + 107 renderer smoke + 15 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
 CI: `uv run pytest` + GUI tests + **actionlint workflow lint** (`rhysd/actionlint@v1.7.12` gate, #444 — workflow 解析错误在 PR CI 即失败，如 `if:` secrets 上下文)
 Re-trigger: `scripts/re-trigger-ci.sh [branch]` (workflow_dispatch, #527 — 替代空 commit 重触发：Actions outage 会整段丢弃 push 事件，dispatch 走 API 路径不受影响)
diff --git a/emrg/server/git_utils.py b/emrg/server/git_utils.py
index 77e69962..94255e2e 100644
--- a/emrg/server/git_utils.py
+++ b/emrg/server/git_utils.py
@@ -23,6 +23,12 @@
 # restarted without PATH git and cycles were silently skipped for 18 min).
 _GIT_MISSING_WARNED = False
 
+# In-process memo of the last (git, gh) paths written to install-info.json —
+# resolve_git_gh() is called on every git_cmd(), and each call used to do an
+# atomic tmp+os.replace disk write even when nothing changed. Tool paths are
+# stable within a process lifetime, so write once and skip the rest.
+_LAST_CACHED_PATHS: tuple[str, str] | None = None
+
 
 # ── Non-interactive subprocess environment (rant 2026-08-07T10:17:27) ──
 #
@@ -228,6 +234,7 @@ def resolve_git_gh() -> tuple[str, str]:
     Returns (git_path, gh_path). Missing executables yield '' (callers decide
     how to degrade).
     """
+    global _LAST_CACHED_PATHS
     git = _cached_tool_path("git")
     gh = _cached_tool_path("gh")
     if git and Path(git).exists():
@@ -240,7 +247,12 @@ def resolve_git_gh() -> tuple[str, str]:
         gh = _tool_in_install("gh") or (shutil.which("gh") or "")
 
     if git:
-        _cache_tool_paths(git, gh)
+        # Write the cache only when the resolved pair changed since the last
+        # write (or nothing cached yet) — avoids an atomic install-info.json
+        # write on every git_cmd() call. Paths are stable per process.
+        if _LAST_CACHED_PATHS != (git, gh):
+            _cache_tool_paths(git, gh)
+            _LAST_CACHED_PATHS = (git, gh)
     else:
         # git is the failure mode that silently disables evolution (2026-08-12
         # incident) — warn regardless of whether gh resolved. Also skip the
diff --git a/tests/test_git_utils.py b/tests/test_git_utils.py
index aef94b6f..20a766d7 100644
--- a/tests/test_git_utils.py
+++ b/tests/test_git_utils.py
@@ -349,3 +349,27 @@ def fake_cache(git: str, gh: str) -> None:
     warns = [r for r in caplog.records if r.levelno >= logging.WARNING]
     assert len(warns) == 1
     assert "git executable not found" in warns[0].getMessage()
+
+
+def test_resolve_git_gh_writes_cache_once_per_process(monkeypatch):
+    """Cache write happens once per process, not on every git_cmd() call.
+
+    resolve_git_gh() runs on every git_cmd(); before this fix each call did an
+    atomic install-info.json write even when the resolved paths were unchanged.
+    Tool paths are stable within a process lifetime — write once, skip the rest.
+    """
+    from emrg.server import git_utils as gu
+
+    calls = []
+    monkeypatch.setattr(gu, "_cached_tool_path", lambda tool: None)
+    monkeypatch.setattr(gu, "_tool_in_install", lambda tool: None)
+    monkeypatch.setattr(gu.shutil, "which", lambda tool: "/usr/bin/git" if tool == "git" else "/usr/bin/gh")
+    monkeypatch.setattr(gu, "_cache_tool_paths", lambda g, h: calls.append((g, h)))
+    monkeypatch.setattr(gu, "_LAST_CACHED_PATHS", None)
+
+    gu.resolve_git_gh()
+    gu.resolve_git_gh()  # unchanged paths → no second write
+    gu.resolve_git_gh()
+
+    assert len(calls) == 1, f"expected exactly 1 cache write, got {len(calls)}: {calls}"
+    assert calls[0] == ("/usr/bin/git", "/usr/bin/gh")