From 4f2bcada3192fbf491d20f80b60c27711bec84b4 Mon Sep 17 00:00:00 2001
From: Rod Boev <rod.boev@gmail.com>
Date: Sat, 27 Jun 2026 07:06:57 -0400
Subject: [PATCH] fix(#5047): keep sync refresh followers coalesced

---
 api/config.py                                 | 12 +++-
 ...t_issue4756_session_visit_model_refresh.py | 59 +++++++++++++++++++
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/api/config.py b/api/config.py
index 57ed1e13e..7c4a37d41 100644
--- a/api/config.py
+++ b/api/config.py
@@ -6890,9 +6890,15 @@ def get_available_models(*, prefer_cache: bool = False, force_refresh: bool = Fa
         # If another thread is already building, wait for its result instead
         # of re-entering the cold path (avoids duplicate 10s zai load_pool calls).
         if should_wait:
+            wait_timeout = 60.0
+            if force_refresh and _LIVE_REBUILD_BUDGET_SECONDS <= 0:
+                # The legacy synchronous path is explicitly unbounded. A forced
+                # refresh follower should keep coalescing behind that live
+                # rebuild instead of giving up after 60s and duplicating it.
+                wait_timeout = None
             _cache_build_cv.wait_for(
                 lambda: not _cache_build_in_progress and _available_models_cache is not None,
-                timeout=60
+                timeout=wait_timeout
             )
             cached = _get_fresh_memory_models_cache(time.monotonic())
             if cached is not None:
@@ -6928,13 +6934,13 @@ def get_available_models(*, prefer_cache: bool = False, force_refresh: bool = Fa
             and force_refresh_started_at is not None
             and _cache_build_in_progress
         ):
-            remaining_budget = 60.0
+            remaining_budget = None
             if _LIVE_REBUILD_BUDGET_SECONDS > 0:
                 remaining_budget = max(
                     0.0,
                     _LIVE_REBUILD_BUDGET_SECONDS - (time.monotonic() - force_refresh_started_at),
                 )
-            if remaining_budget > 0:
+            if remaining_budget is None or remaining_budget > 0:
                 _cache_build_cv.wait_for(
                     lambda: not _cache_build_in_progress,
                     timeout=remaining_budget,
diff --git a/tests/test_issue4756_session_visit_model_refresh.py b/tests/test_issue4756_session_visit_model_refresh.py
index 3daeb8434..1f876cc1d 100644
--- a/tests/test_issue4756_session_visit_model_refresh.py
+++ b/tests/test_issue4756_session_visit_model_refresh.py
@@ -177,6 +177,65 @@ def test_session_visit_overlapping_stale_calls_coalesce_to_single_live_rebuild(t
     assert rebuild_count == 1
 
 
+def test_force_refresh_sync_followers_wait_past_legacy_timeout(tmp_path, monkeypatch):
+    import api.config as cfg
+    import threading
+
+    _reset_models_memory_cache(monkeypatch)
+    stale_catalog = _catalog("stale-model")
+    rebuilt_catalog = _catalog("rebuilt-model")
+    config_path = tmp_path / "config.yaml"
+    config_path.write_text("{}", encoding="utf-8")
+    cache_path = tmp_path / "models_cache.profile.json"
+    cache_path.write_text("{}", encoding="utf-8")
+    old = time.time() - 600.0
+    os.utime(cache_path, (old, old))
+    fingerprint = {"profile": "demo"}
+    rebuild_count = 0
+    timeout_waits = []
+    original_wait_for = threading.Condition.wait_for
+
+    monkeypatch.setattr(cfg, "_LIVE_REBUILD_BUDGET_SECONDS", 0.0, raising=False)
+    monkeypatch.setattr(cfg, "_get_config_path", lambda: config_path)
+    monkeypatch.setattr(cfg, "_cfg_path", config_path, raising=False)
+    monkeypatch.setattr(cfg, "_cfg_mtime", config_path.stat().st_mtime, raising=False)
+    monkeypatch.setattr(cfg, "_get_models_cache_path", lambda: cache_path)
+    monkeypatch.setattr(cfg, "_load_models_cache_from_disk", lambda: None)
+    monkeypatch.setattr(cfg, "_load_stale_models_cache_from_disk", lambda: stale_catalog)
+    monkeypatch.setattr(cfg, "_models_cache_source_fingerprint", lambda: fingerprint)
+    monkeypatch.setattr(cfg, "_save_models_cache_to_disk", lambda _cache: None)
+
+    def _wait_for(self, predicate, timeout=None):
+        if self is not cfg._cache_build_cv:
+            return original_wait_for(self, predicate, timeout)
+        timeout_waits.append(timeout)
+        if timeout is None:
+            published_at = time.monotonic()
+            cfg._available_models_cache = rebuilt_catalog
+            cfg._available_models_cache_ts = published_at
+            cfg._available_models_live_rebuild_ts = published_at
+            cfg._available_models_cache_source_fingerprint = fingerprint
+            cfg._cache_build_in_progress = False
+            return True
+        if timeout == 60.0:
+            return False
+        return original_wait_for(self, predicate, timeout=timeout)
+
+    def _invoke_models_rebuild(_builder):
+        nonlocal rebuild_count
+        rebuild_count += 1
+        return rebuilt_catalog
+
+    monkeypatch.setattr(cfg, "_cache_build_in_progress", True, raising=False)
+    monkeypatch.setattr(threading.Condition, "wait_for", _wait_for)
+    monkeypatch.setattr(cfg, "_invoke_models_rebuild", _invoke_models_rebuild)
+
+    assert cfg.get_available_models(force_refresh=True) == rebuilt_catalog
+    assert rebuild_count == 0
+    assert None in timeout_waits
+    assert 60.0 not in timeout_waits
+
+
 def test_session_visit_overlapping_stale_calls_do_not_duplicate_over_budget_rebuild(tmp_path, monkeypatch):
     import api.config as cfg
     import threading