Introduce DebugVisitor.show() + tests

[etc/vim.git] / black.py

diff --git a/black.py b/black.py
index bb8ec2e57a074938bff931076db5f0b80dd49304..53d332addada506c5228406c0529b3ea58922ee6 100644 (file)
--- a/black.py
+++ b/black.py
@@ -235,23 +235,36 @@ def format_str(src_contents: str, line_length: int) -> FileContent:
     return dst_contents
 
 
+GRAMMARS = [
+    pygram.python_grammar_no_print_statement_no_exec_statement,
+    pygram.python_grammar_no_print_statement,
+    pygram.python_grammar_no_exec_statement,
+    pygram.python_grammar,
+]
+
+
 def lib2to3_parse(src_txt: str) -> Node:
     """Given a string with source, return the lib2to3 Node."""
     grammar = pygram.python_grammar_no_print_statement
-    drv = driver.Driver(grammar, pytree.convert)
     if src_txt[-1] != '\n':
         nl = '\r\n' if '\r\n' in src_txt[:1024] else '\n'
         src_txt += nl
-    try:
-        result = drv.parse_string(src_txt, True)
-    except ParseError as pe:
-        lineno, column = pe.context[1]
-        lines = src_txt.splitlines()
+    for grammar in GRAMMARS:
+        drv = driver.Driver(grammar, pytree.convert)
         try:
-            faulty_line = lines[lineno - 1]
-        except IndexError:
-            faulty_line = "<line number missing in source>"
-        raise ValueError(f"Cannot parse: {lineno}:{column}: {faulty_line}") from None
+            result = drv.parse_string(src_txt, True)
+            break
+
+        except ParseError as pe:
+            lineno, column = pe.context[1]
+            lines = src_txt.splitlines()
+            try:
+                faulty_line = lines[lineno - 1]
+            except IndexError:
+                faulty_line = "<line number missing in source>"
+            exc = ValueError(f"Cannot parse: {lineno}:{column}: {faulty_line}")
+    else:
+        raise exc from None
 
     if isinstance(result, Leaf):
         result = Node(syms.file_input, [result])
@@ -307,6 +320,15 @@ class DebugVisitor(Visitor[T]):
                 out(f' {node.prefix!r}', fg='green', bold=False, nl=False)
             out(f' {node.value!r}', fg='blue', bold=False)
 
+    @classmethod
+    def show(cls, code: str) -> None:
+        """Pretty-prints a given string of `code`.
+
+        Convenience method for debugging.
+        """
+        v: DebugVisitor[None] = DebugVisitor()
+        list(v.visit(lib2to3_parse(code)))
+
 
 KEYWORDS = set(keyword.kwlist)
 WHITESPACE = {token.DEDENT, token.INDENT, token.NEWLINE}
@@ -406,7 +428,7 @@ class BracketTracker:
         """Returns True if there is an yet unmatched open bracket on the line."""
         return bool(self.bracket_match)
 
-    def max_priority(self, exclude: Iterable[LeafID] =()) -> int:
+    def max_priority(self, exclude: Iterable[LeafID] = ()) -> int:
         """Returns the highest priority of a delimiter found on the line.
 
         Values are consistent with what `is_delimiter()` returns.
@@ -872,14 +894,17 @@ def whitespace(leaf: Leaf) -> str:  # noqa C901
             return SPACE if prevp.type == token.COMMA else NO
 
         if prevp.type == token.EQUAL:
-            if prevp.parent and prevp.parent.type in {
-                syms.arglist,
-                syms.argument,
-                syms.parameters,
-                syms.typedargslist,
-                syms.varargslist,
-            }:
-                return NO
+            if prevp.parent:
+                if prevp.parent.type in {
+                    syms.arglist, syms.argument, syms.parameters, syms.varargslist
+                }:
+                    return NO
+
+                elif prevp.parent.type == syms.typedargslist:
+                    # A bit hacky: if the equal sign has whitespace, it means we
+                    # previously found it's a typed argument.  So, we're using
+                    # that, too.
+                    return prevp.prefix
 
         elif prevp.type == token.DOUBLESTAR:
             if prevp.parent and prevp.parent.type in {
@@ -903,6 +928,17 @@ def whitespace(leaf: Leaf) -> str:  # noqa C901
         ):
             return NO
 
+        elif (
+            prevp.type == token.RIGHTSHIFT
+            and prevp.parent
+            and prevp.parent.type == syms.shift_expr
+            and prevp.prev_sibling
+            and prevp.prev_sibling.type == token.NAME
+            and prevp.prev_sibling.value == 'print'  # type: ignore
+        ):
+            # Python 2 print chevron
+            return NO
+
     elif prev.type in OPENING_BRACKETS:
         return NO
 
@@ -914,7 +950,7 @@ def whitespace(leaf: Leaf) -> str:  # noqa C901
         if not prev or prev.type != token.COMMA:
             return NO
 
-    if p.type == syms.varargslist:
+    elif p.type == syms.varargslist:
         # lambdas
         if t == token.RPAR:
             return NO
@@ -1156,7 +1192,7 @@ def make_comment(content: str) -> str:
 
     if content[0] == '#':
         content = content[1:]
-    if content and content[0] not in {' ', '!', '#'}:
+    if content and content[0] not in ' !:#':
         content = ' ' + content
     return '#' + content
 
@@ -1538,7 +1574,12 @@ def assert_equivalent(src: str, dst: str) -> None:
     try:
         src_ast = ast.parse(src)
     except Exception as exc:
-        raise AssertionError(f"cannot parse source: {exc}") from None
+        major, minor = sys.version_info[:2]
+        raise AssertionError(
+            f"cannot use --safe with this file; failed to parse source file "
+            f"with Python {major}.{minor}'s builtin AST. Re-run with --fast "
+            f"or stop using deprecated Python 2 syntax. AST error message: {exc}"
+        )
 
     try:
         dst_ast = ast.parse(dst)