Add startup debug information (#6780)

jxcl · ilevkivskyi · commit c4a6e40dd582 · 2019-05-06T17:02:09.000-04:00
Implements some ideas from #6544
diff --git a/mypy/build.py b/mypy/build.py
@@ -2399,12 +2399,39 @@ def skipping_ancestor(manager: BuildManager, id: str, path: str, ancestor_for: '
                           severity='note', only_once=True)
 
 
+def log_configuration(manager: BuildManager) -> None:
+    """Output useful configuration information to LOG and TRACE"""
+
+    manager.log()
+    configuration_vars = (
+        ("Mypy Version", __version__),
+        ("Config File", (manager.options.config_file or "Default")),
+        ("Configured Executable", manager.options.python_executable),
+        ("Current Executable", sys.executable),
+        ("Cache Dir", manager.options.cache_dir),
+    )
+
+    for conf_name, conf_value in configuration_vars:
+        manager.log("{:24}{}".format(conf_name + ":", conf_value))
+
+    # Complete list of searched paths can get very long, put them under TRACE
+    for path_type, paths in manager.search_paths._asdict().items():
+        if not paths:
+            manager.trace("No %s" % path_type)
+            continue
+
+        manager.trace("%s:" % path_type)
+
+        for pth in paths:
+            manager.trace("    %s" % pth)
+
+
 # The driver
 
 
 def dispatch(sources: List[BuildSource], manager: BuildManager) -> Graph:
-    manager.log()
-    manager.log("Mypy version %s" % __version__)
+    log_configuration(manager)
+
     t0 = time.time()
     graph = load_graph(sources, manager)
 
