From 8bf3d38c8ce3a4c40da8f6d4adf25ccd03d3e09a Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Fri, 9 Dec 2022 20:50:22 +0000
Subject: [PATCH 1/3] Stubtest: Improve heuristics for determining whether
 global-namespace names are imported

---
 mypy/stubtest.py          | 49 ++++++++++++++++++++++++++++++++++-----
 mypy/test/teststubtest.py |  3 +++
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 5e39b996076b..c31b475f3281 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -15,6 +15,7 @@
 import os
 import pkgutil
 import re
+import symtable
 import sys
 import traceback
 import types
@@ -281,6 +282,35 @@ def _verify_exported_names(
     )
 
 
+def _get_imported_symbol_names(runtime: types.ModuleType) -> frozenset[str] | None:
+    """Retrieve the names in the global namespace which are known to be imported.
+
+    1). Use inspect to retrieve the source code of the module
+    2). Use symtable to parse the source and retrieve names that are known to be imported
+        from other modules.
+
+    If either of the above steps fails, return `None`.
+
+    Note that if a set of names is returned,
+    it won't include names imported via `from foo import *` imports.
+    """
+    try:
+        sourcelines = inspect.getsourcelines(runtime)[0]
+    except (OSError, TypeError, SyntaxError):
+        return None
+
+    source = "".join(sourcelines)
+    if not source.strip():
+        return None
+
+    try:
+        module_symtable = symtable.symtable(source, runtime.__name__, "exec")
+    except SyntaxError:
+        return None
+
+    return frozenset(sym.get_name() for sym in module_symtable.get_symbols() if sym.is_imported())
+
+
 @verify.register(nodes.MypyFile)
 def verify_mypyfile(
     stub: nodes.MypyFile, runtime: MaybeMissing[types.ModuleType], object_path: list[str]
@@ -310,15 +340,22 @@ def verify_mypyfile(
         if not o.module_hidden and (not is_probably_private(m) or hasattr(runtime, m))
     }
 
+    imported_symbols = _get_imported_symbol_names(runtime)
+
     def _belongs_to_runtime(r: types.ModuleType, attr: str) -> bool:
         obj = getattr(r, attr)
-        try:
-            obj_mod = getattr(obj, "__module__", None)
-        except Exception:
+        if isinstance(obj, types.ModuleType):
             return False
-        if obj_mod is not None:
-            return bool(obj_mod == r.__name__)
-        return not isinstance(obj, types.ModuleType)
+        if callable(obj):
+            try:
+                obj_mod = getattr(obj, "__module__", None)
+            except Exception:
+                return False
+            if obj_mod is not None:
+                return bool(obj_mod == r.__name__)
+        if imported_symbols is not None:
+            return attr not in imported_symbols
+        return True
 
     runtime_public_contents = (
         runtime_all_as_set
diff --git a/mypy/test/teststubtest.py b/mypy/test/teststubtest.py
index 812333e3feb4..5e59d8efec63 100644
--- a/mypy/test/teststubtest.py
+++ b/mypy/test/teststubtest.py
@@ -1082,6 +1082,9 @@ def test_missing_no_runtime_all(self) -> Iterator[Case]:
         yield Case(stub="", runtime="import sys", error=None)
         yield Case(stub="", runtime="def g(): ...", error="g")
         yield Case(stub="", runtime="CONSTANT = 0", error="CONSTANT")
+        yield Case(stub="", runtime="import re; constant = re.compile('foo')", error="constant")
+        yield Case(stub="", runtime="from json.scanner import NUMBER_RE", error=None)
+        yield Case(stub="", runtime="from string import ascii_letters", error=None)
 
     @collect_cases
     def test_non_public_1(self) -> Iterator[Case]:

From f132b19c67437da13269c1409be65af6106f092d Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Fri, 9 Dec 2022 22:38:27 +0000
Subject: [PATCH 2/3] Just use `getsource()`, not `getsourcelines()`

---
 mypy/stubtest.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index c31b475f3281..305492df7c73 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -295,11 +295,10 @@ def _get_imported_symbol_names(runtime: types.ModuleType) -> frozenset[str] | No
     it won't include names imported via `from foo import *` imports.
     """
     try:
-        sourcelines = inspect.getsourcelines(runtime)[0]
+        source = inspect.getsource(runtime)
     except (OSError, TypeError, SyntaxError):
         return None
 
-    source = "".join(sourcelines)
     if not source.strip():
         return None
 

From 6543bef34d232d7502446e2986a1acddd02c8a53 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Thu, 22 Dec 2022 13:22:16 +0000
Subject: [PATCH 3/3] Address review

---
 mypy/stubtest.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 305492df7c73..7d656fd69c34 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -300,7 +300,9 @@ def _get_imported_symbol_names(runtime: types.ModuleType) -> frozenset[str] | No
         return None
 
     if not source.strip():
-        return None
+        # The source code for the module was an empty file,
+        # no point in parsing it with symtable
+        return frozenset()
 
     try:
         module_symtable = symtable.symtable(source, runtime.__name__, "exec")