Use the config-file format for per-file configuration overrides

Author: cpennington

mypy/main.py

@@ -16,7 +16,7 @@
 from mypy import util
 from mypy.build import BuildSource, BuildResult, PYTHON_EXTENSIONS
 from mypy.errors import CompileError
-from mypy.options import Options, BuildType
+from mypy.options import Options, BuildType, parse_section, parse_version
 from mypy.report import reporter_classes
 
 from mypy.version import __version__
@@ -119,26 +119,6 @@ def __getattr__(self, name: str) -> Any:
             return getattr(self._standard_namespace, name)
 
 
-def parse_version(v: str) -> Tuple[int, int]:
-    m = re.match(r'\A(\d)\.(\d+)\Z', v)
-    if not m:
-        raise argparse.ArgumentTypeError(
-            "Invalid python version '{}' (expected format: 'x.y')".format(v))
-    major, minor = int(m.group(1)), int(m.group(2))
-    if major == 2:
-        if minor != 7:
-            raise argparse.ArgumentTypeError(
-                "Python 2.{} is not supported (must be 2.7)".format(minor))
-    elif major == 3:
-        if minor <= 2:
-            raise argparse.ArgumentTypeError(
-                "Python 3.{} is not supported (must be 3.3 or higher)".format(minor))
-    else:
-        raise argparse.ArgumentTypeError(
-            "Python major version '{}' out of range (must be 2 or 3)".format(major))
-    return major, minor
-
-
 # Make the help output a little less jarring.
 class AugmentedHelpFormatter(argparse.HelpFormatter):
     def __init__(self, prog: Optional[str]) -> None:
@@ -559,22 +539,6 @@ def get_init_file(dir: str) -> Optional[str]:
     return None
 
 
-# For most options, the type of the default value set in options.py is
-# sufficient, and we don't have to do anything here.  This table
-# exists to specify types for values initialized to None or container
-# types.
-config_types = {
-    'python_version': parse_version,
-    'strict_optional_whitelist': lambda s: s.split(),
-    'custom_typing_module': str,
-    'custom_typeshed_dir': str,
-    'mypy_path': lambda s: [p.strip() for p in re.split('[,:]', s)],
-    'junit_xml': str,
-    # These two are for backwards compatibility
-    'silent_imports': bool,
-    'almost_silent': bool,
-}
-
 SHARED_CONFIG_FILES = ('setup.cfg',)
 
 
@@ -641,67 +605,6 @@ def parse_config_file(options: Options, filename: Optional[str]) -> None:
                 options.per_module_options[pattern] = updates
 
 
-def parse_section(prefix: str, template: Options,
-                  section: Mapping[str, str]) -> Tuple[Dict[str, object], Dict[str, str]]:
-    """Parse one section of a config file.
-
-    Returns a dict of option values encountered, and a dict of report directories.
-    """
-    results = {}  # type: Dict[str, object]
-    report_dirs = {}  # type: Dict[str, str]
-    for key in section:
-        key = key.replace('-', '_')
-        if key in config_types:
-            ct = config_types[key]
-        else:
-            dv = getattr(template, key, None)
-            if dv is None:
-                if key.endswith('_report'):
-                    report_type = key[:-7].replace('_', '-')
-                    if report_type in reporter_classes:
-                        report_dirs[report_type] = section.get(key)
-                    else:
-                        print("%s: Unrecognized report type: %s" % (prefix, key),
-                              file=sys.stderr)
-                    continue
-                print("%s: Unrecognized option: %s = %s" % (prefix, key, section[key]),
-                      file=sys.stderr)
-                continue
-            ct = type(dv)
-        v = None  # type: Any
-        try:
-            if ct is bool:
-                v = section.getboolean(key)  # type: ignore  # Until better stub
-            elif callable(ct):
-                try:
-                    v = ct(section.get(key))
-                except argparse.ArgumentTypeError as err:
-                    print("%s: %s: %s" % (prefix, key, err), file=sys.stderr)
-                    continue
-            else:
-                print("%s: Don't know what type %s should have" % (prefix, key), file=sys.stderr)
-                continue
-        except ValueError as err:
-            print("%s: %s: %s" % (prefix, key, err), file=sys.stderr)
-            continue
-        if key == 'silent_imports':
-            print("%s: silent_imports has been replaced by "
-                  "ignore_missing_imports=True; follow_imports=skip" % prefix, file=sys.stderr)
-            if v:
-                if 'ignore_missing_imports' not in results:
-                    results['ignore_missing_imports'] = True
-                if 'follow_imports' not in results:
-                    results['follow_imports'] = 'skip'
-        if key == 'almost_silent':
-            print("%s: almost_silent has been replaced by "
-                  "follow_imports=error" % prefix, file=sys.stderr)
-            if v:
-                if 'follow_imports' not in results:
-                    results['follow_imports'] = 'error'
-        results[key] = v
-    return results, report_dirs
-
-
 def fail(msg: str) -> None:
     sys.stderr.write('%s\n' % msg)
     sys.exit(1)

mypy/options.py

@@ -1,11 +1,15 @@
+import argparse
+from configparser import RawConfigParser
 import fnmatch
+import os
 import pprint
 import re
 import sys
 
 from typing import Any, Mapping, Optional, Tuple, List, Pattern, Dict
 
 from mypy import defaults
+from mypy.report import reporter_classes
 
 
 class BuildType:
@@ -145,23 +149,49 @@ def clone_for_module(self, module: str, path: Optional[str]) -> 'Options':
             if self.module_matches_pattern(module, pattern):
                 updates.update(self.per_module_options[pattern])
 
-        if path:
+        new_options = Options()
+
+        if path and os.path.exists(path):
+            options_section = []
+            found_options = False
             with open(path) as file_contents:
                 for line in file_contents:
                     if not re.match('\s*#', line):
                         break
-                    match = re.match('\s*#\s*mypy-options:(.*)', line)
-                    if match is not None:
-                        for flag in match.group(1).split(','):
-                            flag = flag.strip()
-                            if flag in self.PER_MODULE_OPTIONS:
-                                updates[flag] = True
-                            else:
-                                print("Warning: {!r} in {} is not a valid per-module option".format(flag, path))
+
+                    if re.match('\s*#\s*\[mypy\]', line):
+                        options_section.append(line.strip().strip('#'))
+                        found_options = True
+                        continue
+
+                    if found_options:
+                        options_section.append(line.strip().strip('#'))
+
+            if found_options:
+                parser = RawConfigParser()
+                parser.read_string("\n".join(options_section))
+                updates, report_dirs = parse_section(
+                    "%s [mypy]" % path,
+                    new_options,
+                    parser['mypy']
+                )
+                if report_dirs:
+                    print("Warning: can't specify new mypy reports "
+                          "in a per-file override (from {})".format(path))
+
+                for option, file_override in updates.items():
+                    if file_override == getattr(new_options, option):
+                        # Skip options that are set to the defaults
+                        continue
+
+                    if option not in self.PER_MODULE_OPTIONS:
+                        print("Warning: {!r} in {} is not a valid "
+                              "per-module option".format(option, path))
+                    else:
+                        updates[option] = file_override
 
         if not updates:
             return self
-        new_options = Options()
         new_options.__dict__.update(self.__dict__)
         new_options.__dict__.update(updates)
         return new_options
@@ -174,3 +204,101 @@ def module_matches_pattern(self, module: str, pattern: Pattern[str]) -> bool:
 
     def select_options_affecting_cache(self) -> Mapping[str, bool]:
         return {opt: getattr(self, opt) for opt in self.OPTIONS_AFFECTING_CACHE}
+
+
+def parse_version(v: str) -> Tuple[int, int]:
+    m = re.match(r'\A(\d)\.(\d+)\Z', v)
+    if not m:
+        raise argparse.ArgumentTypeError(
+            "Invalid python version '{}' (expected format: 'x.y')".format(v))
+    major, minor = int(m.group(1)), int(m.group(2))
+    if major == 2:
+        if minor != 7:
+            raise argparse.ArgumentTypeError(
+                "Python 2.{} is not supported (must be 2.7)".format(minor))
+    elif major == 3:
+        if minor <= 2:
+            raise argparse.ArgumentTypeError(
+                "Python 3.{} is not supported (must be 3.3 or higher)".format(minor))
+    else:
+        raise argparse.ArgumentTypeError(
+            "Python major version '{}' out of range (must be 2 or 3)".format(major))
+    return major, minor
+
+
+# For most options, the type of the default value set in options.py is
+# sufficient, and we don't have to do anything here.  This table
+# exists to specify types for values initialized to None or container
+# types.
+config_types = {
+    'python_version': parse_version,
+    'strict_optional_whitelist': lambda s: s.split(),
+    'custom_typing_module': str,
+    'custom_typeshed_dir': str,
+    'mypy_path': lambda s: [p.strip() for p in re.split('[,:]', s)],
+    'junit_xml': str,
+    # These two are for backwards compatibility
+    'silent_imports': bool,
+    'almost_silent': bool,
+}
+
+
+def parse_section(prefix: str, template: Options,
+                  section: Mapping[str, str]) -> Tuple[Dict[str, object], Dict[str, str]]:
+    """Parse one section of a config file.
+
+    Returns a dict of option values encountered, and a dict of report directories.
+    """
+    results = {}  # type: Dict[str, object]
+    report_dirs = {}  # type: Dict[str, str]
+    for key in section:
+        key = key.replace('-', '_')
+        if key in config_types:
+            ct = config_types[key]
+        else:
+            dv = getattr(template, key, None)
+            if dv is None:
+                if key.endswith('_report'):
+                    report_type = key[:-7].replace('_', '-')
+                    if report_type in reporter_classes:
+                        report_dirs[report_type] = section.get(key)
+                    else:
+                        print("%s: Unrecognized report type: %s" % (prefix, key),
+                              file=sys.stderr)
+                    continue
+                print("%s: Unrecognized option: %s = %s" % (prefix, key, section[key]),
+                      file=sys.stderr)
+                continue
+            ct = type(dv)
+        v = None  # type: Any
+        try:
+            if ct is bool:
+                v = section.getboolean(key)  # type: ignore  # Until better stub
+            elif callable(ct):
+                try:
+                    v = ct(section.get(key))
+                except argparse.ArgumentTypeError as err:
+                    print("%s: %s: %s" % (prefix, key, err), file=sys.stderr)
+                    continue
+            else:
+                print("%s: Don't know what type %s should have" % (prefix, key), file=sys.stderr)
+                continue
+        except ValueError as err:
+            print("%s: %s: %s" % (prefix, key, err), file=sys.stderr)
+            continue
+        if key == 'silent_imports':
+            print("%s: silent_imports has been replaced by "
+                  "ignore_missing_imports=True; follow_imports=skip" % prefix, file=sys.stderr)
+            if v:
+                if 'ignore_missing_imports' not in results:
+                    results['ignore_missing_imports'] = True
+                if 'follow_imports' not in results:
+                    results['follow_imports'] = 'skip'
+        if key == 'almost_silent':
+            print("%s: almost_silent has been replaced by "
+                  "follow_imports=error" % prefix, file=sys.stderr)
+            if v:
+                if 'follow_imports' not in results:
+                    results['follow_imports'] = 'error'
+        results[key] = v
+    return results, report_dirs