Add undefined name warning

Resolves   #843.

coconut/compiler/compiler.py

@@ -246,12 +246,17 @@ def import_stmt(imp_from, imp, imp_as, raw=False):
     )
 
 
-def imported_names(imports):
-    """Yields all the names imported by imports = [[imp1], [imp2, as], ...]."""
+def get_imported_names(imports):
+    """Returns all the names imported by imports = [[imp1], [imp2, as], ...] and whether there is a star import."""
+    saw_names = []
+    saw_star = False
     for imp in imports:
         imp_name = imp[-1].split(".", 1)[0]
-        if imp_name != "*":
-            yield imp_name
+        if imp_name == "*":
+            saw_star = True
+        else:
+            saw_names.append(imp_name)
+    return saw_names, saw_star
 
 
 def special_starred_import_handle(imp_all=False):
@@ -529,7 +534,8 @@ def reset(self, keep_state=False, filename=None):
         # but always overwrite temp_vars_by_key since they store locs that will be invalidated
         self.temp_vars_by_key = {}
         self.parsing_context = defaultdict(list)
-        self.unused_imports = defaultdict(list)
+        self.name_info = defaultdict(lambda: {"imported": [], "referenced": [], "assigned": []})
+        self.star_import = False
         self.kept_lines = []
         self.num_lines = 0
         self.disable_name_check = False
@@ -942,6 +948,11 @@ def strict_err(self, *args, **kwargs):
         if self.strict:
             raise self.make_err(CoconutStyleError, *args, **kwargs)
 
+    def strict_warn(self, *args, **kwargs):
+        internal_assert("extra" not in kwargs, "cannot pass extra=... to strict_warn")
+        if self.strict:
+            self.syntax_warning(*args, extra="remove --strict to dismiss", **kwargs)
+
     def syntax_warning(self, message, original, loc, **kwargs):
         """Show a CoconutSyntaxWarning. Usage:
             self.syntax_warning(message, original, loc)
@@ -1319,21 +1330,30 @@ def streamline(self, grammars, inputstring=None, force=False, inner=False):
             elif inputstring is not None and not inner:
                 logger.log("No streamlining done for input of length {length}.".format(length=input_len))
 
+    def qa_error(self, msg, original, loc):
+        """Strict error or warn an error that should be disabled by a NOQA comment."""
+        ln = self.adjust(lineno(loc, original))
+        comment = self.reformat(" ".join(self.comments[ln]), ignore_errors=True)
+        if not self.noqa_regex.search(comment):
+            self.strict_err_or_warn(
+                msg + " (add '# NOQA' to suppress)",
+                original,
+                loc,
+                endpoint=False,
+            )
+
     def run_final_checks(self, original, keep_state=False):
         """Run post-parsing checks to raise any necessary errors/warnings."""
-        # only check for unused imports if we're not keeping state accross parses
+        # only check for unused imports/etc. if we're not keeping state accross parses
         if not keep_state:
-            for name, locs in self.unused_imports.items():
-                for loc in locs:
-                    ln = self.adjust(lineno(loc, original))
-                    comment = self.reformat(" ".join(self.comments[ln]), ignore_errors=True)
-                    if not self.noqa_regex.search(comment):
-                        self.strict_err_or_warn(
-                            "found unused import " + repr(self.reformat(name, ignore_errors=True)) + " (add '# NOQA' to suppress)",
-                            original,
-                            loc,
-                            endpoint=False,
-                        )
+            for name, info in self.name_info.items():
+                if info["imported"] and not info["referenced"]:
+                    for loc in info["imported"]:
+                        self.qa_error("found unused import " + repr(self.reformat(name, ignore_errors=True)), original, loc)
+                if not self.star_import:  # only check for undefined names when there are no * imports
+                    if name not in all_builtins and info["referenced"] and not (info["assigned"] or info["imported"]):
+                        for loc in info["referenced"]:
+                            self.qa_error("found undefined name " + repr(self.reformat(name, ignore_errors=True)), original, loc)
 
     def parse_line_by_line(self, init_parser, line_parser, original):
         """Apply init_parser then line_parser repeatedly."""
@@ -3731,13 +3751,17 @@ def import_handle(self, original, loc, tokens):
         else:
             raise CoconutInternalException("invalid import tokens", tokens)
         imports = list(imports)
-        if imp_from == "*" or imp_from is None and "*" in imports:
+        imported_names, star_import = get_imported_names(imports)
+        self.star_import = self.star_import or star_import
+        if star_import:
+            self.strict_warn("found * import; these disable Coconut's undefined name detection", original, loc)
+        if imp_from == "*" or (imp_from is None and star_import):
             if not (len(imports) == 1 and imports[0] == "*"):
                 raise self.make_err(CoconutSyntaxError, "only [from *] import * allowed, not from * import name", original, loc)
             self.syntax_warning("[from *] import * is a Coconut Easter egg and should not be used in production code", original, loc)
             return special_starred_import_handle(imp_all=bool(imp_from))
-        for imp_name in imported_names(imports):
-            self.unused_imports[imp_name].append(loc)
+        for imp_name in imported_names:
+            self.name_info[imp_name]["imported"].append(loc)
         return self.universal_import(loc, imports, imp_from=imp_from)
 
     def complex_raise_stmt_handle(self, loc, tokens):
@@ -4989,8 +5013,10 @@ def name_handle(self, original, loc, tokens, assign=False, classname=False, expr
                             )
                         return typevars[name]
 
-        if not assign:
-            self.unused_imports.pop(name, None)
+        if assign:
+            self.name_info[name]["assigned"].append(loc)
+        else:
+            self.name_info[name]["referenced"].append(loc)
 
         if (
             assign

coconut/constants.py

@@ -607,15 +607,20 @@ def get_path_env_var(env_var, default):
     "tuple", "type",
     "vars",
     "zip",
+    'Ellipsis',
     "__import__",
     '__name__',
     '__file__',
     '__annotations__',
     '__debug__',
+    '__build_class__',
+    '__loader__',
+    '__package__',
+    '__spec__',
 )
 
 python_exceptions = (
-    "BaseException", "BaseExceptionGroup", "GeneratorExit", "KeyboardInterrupt", "SystemExit", "Exception", "ArithmeticError", "FloatingPointError", "OverflowError", "ZeroDivisionError", "AssertionError", "AttributeError", "BufferError", "EOFError", "ExceptionGroup", "BaseExceptionGroup", "ImportError", "ModuleNotFoundError", "LookupError", "IndexError", "KeyError", "MemoryError", "NameError", "UnboundLocalError", "OSError", "BlockingIOError", "ChildProcessError", "ConnectionError", "BrokenPipeError", "ConnectionAbortedError", "ConnectionRefusedError", "ConnectionResetError", "FileExistsError", "FileNotFoundError", "InterruptedError", "IsADirectoryError", "NotADirectoryError", "PermissionError", "ProcessLookupError", "TimeoutError", "ReferenceError", "RuntimeError", "NotImplementedError", "RecursionError", "StopAsyncIteration", "StopIteration", "SyntaxError", "IndentationError", "TabError", "SystemError", "TypeError", "ValueError", "UnicodeError", "UnicodeDecodeError", "UnicodeEncodeError", "UnicodeTranslateError", "Warning", "BytesWarning", "DeprecationWarning", "EncodingWarning", "FutureWarning", "ImportWarning", "PendingDeprecationWarning", "ResourceWarning", "RuntimeWarning", "SyntaxWarning", "UnicodeWarning", "UserWarning",
+    'ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException', 'BaseExceptionGroup', 'BlockingIOError', 'BrokenPipeError', 'BufferError', 'BytesWarning', 'ChildProcessError', 'ConnectionAbortedError', 'ConnectionError', 'ConnectionRefusedError', 'ConnectionResetError', 'DeprecationWarning', 'EOFError', 'EncodingWarning', 'EnvironmentError', 'Exception', 'ExceptionGroup', 'FileExistsError', 'FileNotFoundError', 'FloatingPointError', 'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError', 'ImportWarning', 'IndentationError', 'IndexError', 'InterruptedError', 'IsADirectoryError', 'KeyError', 'KeyboardInterrupt', 'LookupError', 'MemoryError', 'ModuleNotFoundError', 'NameError', 'NotADirectoryError', 'NotImplemented', 'NotImplementedError', 'OSError', 'OverflowError', 'PendingDeprecationWarning', 'PermissionError', 'ProcessLookupError', 'RecursionError', 'ReferenceError', 'ResourceWarning', 'RuntimeError', 'RuntimeWarning', 'StopAsyncIteration', 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError', 'SystemExit', 'TabError', 'TimeoutError', 'TypeError', 'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError', 'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning', 'ValueError', 'Warning', 'WindowsError', 'ZeroDivisionError'
 )
 
 always_keep_parse_name_prefix = "HAS_"

coconut/root.py

@@ -26,7 +26,7 @@
 VERSION = "3.1.1"
 VERSION_NAME = None
 # False for release, int >= 1 for develop
-DEVELOP = 1
+DEVELOP = 2
 ALPHA = False  # for pre releases rather than post releases
 
 assert DEVELOP is False or DEVELOP >= 1, "DEVELOP must be False or an int >= 1"

coconut/tests/src/cocotest/agnostic/primary_1.coco

@@ -90,7 +90,7 @@ def primary_test_1() -> bool:
     \\assert data == 3
     \\def backslash_test():
         return (x) -> x
-    assert \(1) == 1 == backslash_test()(1)
+    assert \(1) == 1 == backslash_test()(1)  # NOQA
     assert True is (\(
             "hello"
         ) == "hello" == \(
@@ -100,7 +100,7 @@ def primary_test_1() -> bool:
                                    x,
                                    y):
         return x + y
-    assert multiline_backslash_test(1, 2) == 3
+    assert multiline_backslash_test(1, 2) == 3  # noqa
     \\ assert True
     class one_line_class: pass
     assert isinstance(one_line_class(), one_line_class)

coconut/tests/src/cocotest/agnostic/tutorial.coco

@@ -22,13 +22,15 @@ assert range(1, 5) |> product == 24
 first_five_words = .split() ..> .$[:5] ..> " ".join
 assert first_five_words("ab cd ef gh ij kl") == "ab cd ef gh ij"
 
-@recursive_iterator
+# TODO: recursive_iterator -> recursive_generator
+@recursive_iterator  # noqa
 def fib() = (1, 1) :: map((+), fib(), fib()$[1:])
 assert fib()$[:5] |> list == [1, 1, 2, 3, 5]
 
+# TODO: parallel_map -> process_map
 # can't use parallel_map here otherwise each process would have to rerun all
 #  the tutorial tests since we don't guard them behind __name__ == "__main__"
-assert range(100) |> concurrent_map$(.**2) |> list |> .$[-1] == 9801
+assert range(100) |> thread_map$(.**2) |> list |> .$[-1] == 9801
 
 def factorial(n, acc=1):
     match n:

coconut/tests/src/cocotest/target_2/py2_test.coco

@@ -4,5 +4,5 @@ def py2_test() -> bool:
     assert py_map((+)$(2), range(5)) == [2, 3, 4, 5, 6]
     assert py_range(5) == [0, 1, 2, 3, 4]
     assert not isinstance(long(1), py_int)  # type: ignore
-    assert py_str(3) == b"3" == unicode(b"3")  # type: ignore
+    assert py_str(3) == b"3" == unicode(b"3")  # noqa  # type: ignore
     return True

coconut/tests/src/extras.coco

@@ -414,6 +414,16 @@ import abc
     except CoconutStyleError as err:
         assert str(err) == """found unused import 'abc' (add '# NOQA' to suppress) (remove --strict to downgrade to a warning) (line 1)
   import abc"""
+    try:
+        parse("""
+1
+2 + x
+3
+        """.strip())
+    except CoconutStyleError as err:
+        assert str(err) == """found undefined name 'x' (add '# NOQA' to suppress) (remove --strict to downgrade to a warning) (line 2)
+  2 + x
+      ^"""
     assert_raises(-> parse("""
 class A(object):
     1