Retry a slow first databricks --version before giving up

src/ucode/databricks.py

@@ -786,15 +786,30 @@ def perms_ok(path: str) -> bool:
     return found
 
 
+# The first `--version` probe's budget, then one longer retry for a slow cold start.
+_DATABRICKS_CLI_VERSION_TIMEOUTS_SECONDS = (10, 60)
+
+
 def _read_databricks_cli_version(path: str) -> tuple[int, int, int] | None:
     """Run ``<path> --version`` and parse it. None on any subprocess or parse failure.
 
     Used only by discovery, which is what establishes ``path`` in the first
     place — every other caller reads a version through ``databricks_cli_path()``.
+    A first run can be slow (e.g. macOS verifying a freshly upgraded binary), so a
+    timed-out probe is retried once with a longer budget before giving up.
     """
-    try:
-        result = run([path, "--version"], check=False, capture_output=True, text=True, timeout=10)
-    except (OSError, subprocess.TimeoutExpired):
+    result = None
+    for timeout in _DATABRICKS_CLI_VERSION_TIMEOUTS_SECONDS:
+        try:
+            result = run(
+                [path, "--version"], check=False, capture_output=True, text=True, timeout=timeout
+            )
+            break
+        except subprocess.TimeoutExpired:
+            continue
+        except OSError:
+            return None
+    if result is None:
         return None
     raw = result.stdout or result.stderr or ""
     output = (raw if isinstance(raw, str) else raw.decode(errors="replace")).strip()

tests/test_databricks.py

@@ -4402,11 +4402,29 @@ def boom(*a, **kw):
         assert db_mod._read_databricks_cli_version("/usr/bin/databricks") is None
 
     def test_read_version_swallows_timeout(self, monkeypatch):
+        timeouts = []
+
         def boom(*a, **kw):
-            raise subprocess.TimeoutExpired("databricks", 10)
+            timeouts.append(kw["timeout"])
+            raise subprocess.TimeoutExpired("databricks", kw["timeout"])
 
         monkeypatch.setattr(db_mod, "run", boom)
         assert db_mod._read_databricks_cli_version("/usr/bin/databricks") is None
+        assert timeouts == [10, 60]
+
+    def test_read_version_retries_a_slow_first_run(self, monkeypatch):
+        """A cold `--version` that outlasts the first budget is read on the longer retry."""
+        timeouts = []
+
+        def slow_then_ok(*a, **kw):
+            timeouts.append(kw["timeout"])
+            if len(timeouts) == 1:
+                raise subprocess.TimeoutExpired("databricks", kw["timeout"])
+            return subprocess.CompletedProcess(a, 0, "Databricks CLI v1.20.0", "")
+
+        monkeypatch.setattr(db_mod, "run", slow_then_ok)
+        assert db_mod._read_databricks_cli_version("/usr/bin/databricks") == (1, 20, 0)
+        assert timeouts == [10, 60]
 
     def test_read_version_parses_output(self, monkeypatch):
         monkeypatch.setattr(