update linecache to 3.13.3

Lib/linecache.py

@@ -5,17 +5,13 @@ is not found, it will look down the module search path for a file by
 that name.
 """
 
-import functools
-import sys
-import os
-import tokenize
-
 __all__ = ["getline", "clearcache", "checkcache", "lazycache"]
 
 
 # The cache. Maps filenames to either a thunk which will provide source code,
 # or a tuple (size, mtime, lines, fullname) once loaded.
 cache = {}
+_interactive_cache = {}
 
 
 def clearcache():
@@ -49,28 +45,54 @@ def getlines(filename, module_globals=None):
         return []
 
 
+def _getline_from_code(filename, lineno):
+    lines = _getlines_from_code(filename)
+    if 1 <= lineno <= len(lines):
+        return lines[lineno - 1]
+    return ''
+
+def _make_key(code):
+    return (code.co_filename, code.co_qualname, code.co_firstlineno)
+
+def _getlines_from_code(code):
+    code_id = _make_key(code)
+    if code_id in _interactive_cache:
+        entry = _interactive_cache[code_id]
+        if len(entry) != 1:
+            return _interactive_cache[code_id][2]
+    return []
+
+
 def checkcache(filename=None):
     """Discard cache entries that are out of date.
     (This is not checked upon each call!)"""
 
     if filename is None:
-        filenames = list(cache.keys())
-    elif filename in cache:
-        filenames = [filename]
+        # get keys atomically
+        filenames = cache.copy().keys()
     else:
-        return
+        filenames = [filename]
 
     for filename in filenames:
-        entry = cache[filename]
+        try:
+            entry = cache[filename]
+        except KeyError:
+            continue
+
         if len(entry) == 1:
             # lazy cache entry, leave it lazy.
             continue
         size, mtime, lines, fullname = entry
         if mtime is None:
             continue   # no-op for files loaded via a __loader__
+        try:
+            # This import can fail if the interpreter is shutting down
+            import os
+        except ImportError:
+            return
         try:
             stat = os.stat(fullname)
-        except OSError:
+        except (OSError, ValueError):
             cache.pop(filename, None)
             continue
         if size != stat.st_size or mtime != stat.st_mtime:
@@ -82,6 +104,17 @@ def updatecache(filename, module_globals=None):
     If something's wrong, print a message, discard the cache entry,
     and return an empty list."""
 
+    # These imports are not at top level because linecache is in the critical
+    # path of the interpreter startup and importing os and sys take a lot of time
+    # and slows down the startup sequence.
+    try:
+        import os
+        import sys
+        import tokenize
+    except ImportError:
+        # These import can fail if the interpreter is shutting down
+        return []
+
     if filename in cache:
         if len(cache[filename]) != 1:
             cache.pop(filename, None)
@@ -128,16 +161,20 @@ def updatecache(filename, module_globals=None):
             try:
                 stat = os.stat(fullname)
                 break
-            except OSError:
+            except (OSError, ValueError):
                 pass
         else:
             return []
+    except ValueError:  # may be raised by os.stat()
+        return []
     try:
         with tokenize.open(fullname) as fp:
             lines = fp.readlines()
     except (OSError, UnicodeDecodeError, SyntaxError):
         return []
-    if lines and not lines[-1].endswith('\n'):
+    if not lines:
+        lines = ['\n']
+    elif not lines[-1].endswith('\n'):
         lines[-1] += '\n'
     size, mtime = stat.st_size, stat.st_mtime
     cache[filename] = size, mtime, lines, fullname
@@ -166,17 +203,29 @@ def lazycache(filename, module_globals):
         return False
     # Try for a __loader__, if available
     if module_globals and '__name__' in module_globals:
-        name = module_globals['__name__']
-        if (loader := module_globals.get('__loader__')) is None:
-            if spec := module_globals.get('__spec__'):
-                try:
-                    loader = spec.loader
-                except AttributeError:
-                    pass
+        spec = module_globals.get('__spec__')
+        name = getattr(spec, 'name', None) or module_globals['__name__']
+        loader = getattr(spec, 'loader', None)
+        if loader is None:
+            loader = module_globals.get('__loader__')
         get_source = getattr(loader, 'get_source', None)
 
         if name and get_source:
-            get_lines = functools.partial(get_source, name)
+            def get_lines(name=name, *args, **kwargs):
+                return get_source(name, *args, **kwargs)
             cache[filename] = (get_lines,)
             return True
     return False
+
+def _register_code(code, string, name):
+    entry = (len(string),
+             None,
+             [line + '\n' for line in string.splitlines()],
+             name)
+    stack = [code]
+    while stack:
+        code = stack.pop()
+        for const in code.co_consts:
+            if isinstance(const, type(code)):
+                stack.append(const)
+        _interactive_cache[_make_key(code)] = entry

Lib/test/test_linecache.py

@@ -5,8 +5,10 @@ import unittest
 import os.path
 import tempfile
 import tokenize
+from importlib.machinery import ModuleSpec
 from test import support
 from test.support import os_helper
+from test.support.script_helper import assert_python_ok
 
 
 FILENAME = linecache.__file__
@@ -82,6 +84,10 @@ class GetLineTestsBadData(TempFile):
 class EmptyFile(GetLineTestsGoodData, unittest.TestCase):
     file_list = []
 
+    def test_getlines(self):
+        lines = linecache.getlines(self.file_name)
+        self.assertEqual(lines, ['\n'])
+
 
 class SingleEmptyLine(GetLineTestsGoodData, unittest.TestCase):
     file_list = ['\n']
@@ -97,6 +103,16 @@ class BadUnicode_WithDeclaration(GetLineTestsBadData, unittest.TestCase):
     file_byte_string = b'# coding=utf-8\n\x80abc'
 
 
+class FakeLoader:
+    def get_source(self, fullname):
+        return f'source for {fullname}'
+
+
+class NoSourceLoader:
+    def get_source(self, fullname):
+        return None
+
+
 class LineCacheTests(unittest.TestCase):
 
     def test_getline(self):
@@ -238,6 +254,70 @@ class LineCacheTests(unittest.TestCase):
         self.assertEqual(lines3, [])
         self.assertEqual(linecache.getlines(FILENAME), lines)
 
+    def test_loader(self):
+        filename = 'scheme://path'
+
+        for loader in (None, object(), NoSourceLoader()):
+            linecache.clearcache()
+            module_globals = {'__name__': 'a.b.c', '__loader__': loader}
+            self.assertEqual(linecache.getlines(filename, module_globals), [])
+
+        linecache.clearcache()
+        module_globals = {'__name__': 'a.b.c', '__loader__': FakeLoader()}
+        self.assertEqual(linecache.getlines(filename, module_globals),
+                         ['source for a.b.c\n'])
+
+        for spec in (None, object(), ModuleSpec('', FakeLoader())):
+            linecache.clearcache()
+            module_globals = {'__name__': 'a.b.c', '__loader__': FakeLoader(),
+                              '__spec__': spec}
+            self.assertEqual(linecache.getlines(filename, module_globals),
+                             ['source for a.b.c\n'])
+
+        linecache.clearcache()
+        spec = ModuleSpec('x.y.z', FakeLoader())
+        module_globals = {'__name__': 'a.b.c', '__loader__': spec.loader,
+                          '__spec__': spec}
+        self.assertEqual(linecache.getlines(filename, module_globals),
+                         ['source for x.y.z\n'])
+
+    def test_invalid_names(self):
+        for name, desc in [
+            ('\x00', 'NUL bytes filename'),
+            (__file__ + '\x00', 'filename with embedded NUL bytes'),
+            # A filename with surrogate codes. A UnicodeEncodeError is raised
+            # by os.stat() upon querying, which is a subclass of ValueError.
+            ("\uD834\uDD1E.py", 'surrogate codes (MUSICAL SYMBOL G CLEF)'),
+            # For POSIX platforms, an OSError will be raised but for Windows
+            # platforms, a ValueError is raised due to the path_t converter.
+            # See: https://github.com/python/cpython/issues/122170
+            ('a' * 1_000_000, 'very long filename'),
+        ]:
+            with self.subTest(f'updatecache: {desc}'):
+                linecache.clearcache()
+                lines = linecache.updatecache(name)
+                self.assertListEqual(lines, [])
+                self.assertNotIn(name, linecache.cache)
+
+            # hack into the cache (it shouldn't be allowed
+            # but we never know what people do...)
+            for key, fullname in [(name, 'ok'), ('key', name), (name, name)]:
+                with self.subTest(f'checkcache: {desc}',
+                                  key=key, fullname=fullname):
+                    linecache.clearcache()
+                    linecache.cache[key] = (0, 1234, [], fullname)
+                    linecache.checkcache(key)
+                    self.assertNotIn(key, linecache.cache)
+
+        # just to be sure that we did not mess with cache
+        linecache.clearcache()
+
+    def test_linecache_python_string(self):
+        cmdline = "import linecache;assert len(linecache.cache) == 0"
+        retcode, stdout, stderr = assert_python_ok('-c', cmdline)
+        self.assertEqual(retcode, 0)
+        self.assertEqual(stdout, b'')
+        self.assertEqual(stderr, b'')
 
 class LineCacheInvalidationTests(unittest.TestCase):
     def setUp(self):