From 98f8b96b1163f8c16dfa0157b801fa53c327e185 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Sun, 2 Aug 2020 14:02:26 -0700
Subject: [PATCH] Pass module-specific Options to fastparse.parse()

Before this, per-module flags that are handled in fastparse (in
particular no_implicit_optional) were seeing the flag's global value.

Fixes #9208
---
 mypy/build.py                   |  8 +++++---
 test-data/unit/check-flags.test | 29 +++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index f372f3d087a1..8d84196af642 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -762,13 +762,14 @@ def is_module(self, id: str) -> bool:
         """Is there a file in the file system corresponding to module id?"""
         return find_module_simple(id, self) is not None
 
-    def parse_file(self, id: str, path: str, source: str, ignore_errors: bool) -> MypyFile:
+    def parse_file(self, id: str, path: str, source: str, ignore_errors: bool,
+                   options: Options) -> MypyFile:
         """Parse the source of a file with the given name.
 
         Raise CompileError if there is a parse error.
         """
         t0 = time.time()
-        tree = parse(source, path, id, self.errors, options=self.options)
+        tree = parse(source, path, id, self.errors, options=options)
         tree._fullname = id
         self.add_stats(files_parsed=1,
                        modules_parsed=int(not tree.is_stub),
@@ -2001,7 +2002,8 @@ def parse_file(self) -> None:
 
             self.parse_inline_configuration(source)
             self.tree = manager.parse_file(self.id, self.xpath, source,
-                                           self.ignore_all or self.options.ignore_errors)
+                                           self.ignore_all or self.options.ignore_errors,
+                                           self.options)
 
         modules[self.id] = self.tree
 
diff --git a/test-data/unit/check-flags.test b/test-data/unit/check-flags.test
index 37b2c2a92e68..0e23476c4d0e 100644
--- a/test-data/unit/check-flags.test
+++ b/test-data/unit/check-flags.test
@@ -1501,3 +1501,32 @@ class ShouldNotBeFine(x): ...  # E: Class cannot subclass 'x' (has type 'Any')
 disallow_subclassing_any = True
 \[mypy-m]
 disallow_subclassing_any = False
+
+[case testNoImplicitOptionalPerModule]
+# flags: --config-file tmp/mypy.ini
+import m
+
+[file m.py]
+def f(a: str = None) -> int:
+    return 0
+
+[file mypy.ini]
+\[mypy]
+no_implicit_optional = True
+\[mypy-m]
+no_implicit_optional = False
+
+[case testNoImplicitOptionalPerModulePython2]
+# flags: --config-file tmp/mypy.ini --python-version 2.7
+import m
+
+[file m.py]
+def f(a = None):
+    # type: (str) -> int
+    return 0
+
+[file mypy.ini]
+\[mypy]
+no_implicit_optional = True
+\[mypy-m]
+no_implicit_optional = False