Merge pull request #4 from MichaelKim0407/develop

release 1.1

.github/workflows/python-publish.yml

@@ -0,0 +1,31 @@
+# This workflows will upload a Python Package using Twine when a release is created
+# For more information see: https://help.github.com/en/actions/language-and-framework-guides/using-python-with-github-actions#publishing-to-package-registries
+
+name: Upload Python Package
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  deploy:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install setuptools twine
+      - name: Build and publish
+        env:
+          TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
+          TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
+        run: |
+          python setup.py sdist
+          twine upload dist/*

.gitignore

@@ -16,5 +16,8 @@ dist/
 .pytest_cache/
 .coverage
 
+# mypy
+.mypy_cache/
+
 # System
 .DS_Store

README.md

@@ -1,7 +1,11 @@
 # flake8-use-fstring
 
-[![Build Status](https://travis-ci.com/MichaelKim0407/flake8-use-fstring.svg?branch=master)](https://travis-ci.com/MichaelKim0407/flake8-use-fstring)
-[![Coverage Status](https://coveralls.io/repos/github/MichaelKim0407/flake8-use-fstring/badge.svg?branch=master)](https://coveralls.io/github/MichaelKim0407/flake8-use-fstring?branch=master)
+* `master` (release)
+    [![Build Status](https://travis-ci.com/MichaelKim0407/flake8-use-fstring.svg?branch=master)](https://travis-ci.com/MichaelKim0407/flake8-use-fstring)
+    [![Coverage Status](https://coveralls.io/repos/github/MichaelKim0407/flake8-use-fstring/badge.svg?branch=master)](https://coveralls.io/github/MichaelKim0407/flake8-use-fstring?branch=master)
+* `develop` (main)
+    [![Build Status](https://travis-ci.com/MichaelKim0407/flake8-use-fstring.svg?branch=develop)](https://travis-ci.com/MichaelKim0407/flake8-use-fstring)
+    [![Coverage Status](https://coveralls.io/repos/github/MichaelKim0407/flake8-use-fstring/badge.svg?branch=develop)](https://coveralls.io/github/MichaelKim0407/flake8-use-fstring?branch=develop)
 
 Jump-start into modern Python by forcing yourself to use f-strings.
 
@@ -19,9 +23,11 @@ pip install flake8-use-fstring
 
 * `FS002`: `.format` formatting is used.
 
+* `FS003`: f-string missing prefix (ignored by default).
+
 ## Available Configurations
 
-### `--percent-greedy` and `--format-greedy`
+### `--percent-greedy`, `--format-greedy`, and `--fstring-ignore-format`
 
 This plugin checks each python statement (logical line)
 and see if `%` or `.format` is used.
@@ -45,5 +51,18 @@ Thus level 0 is the default level.
 However, for most projects it should be reasonable to use greedy level 2 with confidence.
 
 To set greedy levels,
-set `--percent-greedy` and `--format-greedy` in the command line,
-or set `percent-greedy` and `format-greedy` in the `.flake8` config file.
+set `--percent-greedy=<level>` and `--format-greedy=<level>` in the command line,
+or set `percent-greedy=<level>` and `format-greedy=<level>` in the `.flake8` config file.
+
+Optionally, this plugin can also check for strings that appear to be intended to be f-strings
+but are missing the `f` prefix.
+This check is meant to assist when converting code to use f-strings.
+Due to the potential for false positives, this check (`FS003`) is disabled by default.
+To enable this check,
+add the `--enable-extensions=FS003` command line option,
+or set `enable-extensions=FS003` in the `.flake8` config file.
+
+The missing prefix check normally ignores strings that are using `%` or `.format` formatting,
+to check those strings as well,
+add the `--fstring-ignore-format` command line option,
+or set `fstring-ignore-format=True` in the `.flake8` config file.

flake8_use_fstring/__init__.py

@@ -1 +1 @@
-__version__ = '1.0'
+__version__ = '1.1'

flake8_use_fstring/base.py

@@ -8,6 +8,8 @@
     OptionManager as _OptionManager,
 )
 
+Flake8Output = _typing.Tuple[_typing.Tuple[int, int], str]
+
 
 class BaseLogicalLineChecker(object):
     def __init__(
@@ -24,7 +26,15 @@ def __getitem__(self, i: int) -> bool:
     def __call__(self, i: int) -> str:
         raise NotImplementedError  # pragma: no cover
 
-    def __iter__(self) -> _typing.Iterator[_typing.Tuple[int, str]]:
+    def __iter__(self) -> _typing.Iterator[Flake8Output]:
+        for i in range(len(self.tokens)):
+            if not self[i]:
+                continue
+            yield self.tokens[i].start, self(i)
+
+
+class BaseGreedyLogicalLineChecker(BaseLogicalLineChecker):
+    def __iter__(self) -> _typing.Iterator[Flake8Output]:
         met_string = False
 
         for i in range(len(self.tokens)):

flake8_use_fstring/format.py

@@ -1,7 +1,7 @@
 import token as _token
 
 from .base import (
-    BaseLogicalLineChecker as _Base,
+    BaseGreedyLogicalLineChecker as _Base,
 )
 
 

flake8_use_fstring/percent.py

@@ -1,7 +1,7 @@
 import token as _token
 
 from .base import (
-    BaseLogicalLineChecker as _Base,
+    BaseGreedyLogicalLineChecker as _Base,
 )
 
 

flake8_use_fstring/prefix.py

@@ -0,0 +1,70 @@
+import re as _re
+import token as _token
+
+from flake8.options.manager import (
+    OptionManager as _OptionManager,
+)
+
+from .base import (
+    BaseLogicalLineChecker as _Base,
+)
+
+FSTRING_REGEX = _re.compile(r'^([a-zA-Z]*?[fF][a-zA-Z]*?){1}["\']')
+NON_FSTRING_REGEX = _re.compile(
+    r'^[a-zA-Z]*(?:\'\'\'|\'|"""|")(.*?{.+?}.*)(?:\'|\'\'\'|"|""")$',
+)
+
+
+class MissingPrefixDetector(_Base):
+    name = 'use-fstring-prefix'
+    version = '1.0'
+    ignore_format = False
+    off_by_default = True
+
+    def __getitem__(self, i: int) -> bool:
+        token = self.tokens[i]
+        if token.exact_type != _token.STRING:
+            return False
+
+        if FSTRING_REGEX.search(token.string):  # already is an f-string
+            return False
+
+        if not self.ignore_format:
+            # look ahead for % or .format and skip if present
+            for next_i, next_token in enumerate(self.tokens[i + 1:], i + 1):
+                if next_token.exact_type == _token.STRING:
+                    continue
+                if next_token.exact_type == _token.PERCENT:
+                    return False
+                if next_token.exact_type == _token.DOT:
+                    try:
+                        next_token = self.tokens[next_i + 1]
+                        if next_token.exact_type != _token.NAME:
+                            break
+                        if next_token.string == 'format':
+                            return False
+                    except IndexError:
+                        pass
+                break
+
+        value = token.string.replace('{{', '').replace('}}', '')
+        return NON_FSTRING_REGEX.search(value) is not None
+
+    def __call__(self, i: int) -> str:
+        return 'FS003 f-string missing prefix'
+
+    @classmethod
+    def add_options(cls, option_manager: _OptionManager):
+        option_manager.add_option(
+            f'--{cls.OPTION_NAME}',
+            action='store_true',
+            default=False,
+            parse_from_config=True,
+        )
+
+    @classmethod
+    def parse_options(cls, options):
+        option_var = cls.OPTION_NAME.replace('-', '_')
+        cls.ignore_format = vars(options)[option_var]
+
+    OPTION_NAME = 'fstring-ignore-format'

setup.py

@@ -3,6 +3,7 @@
 from flake8_use_fstring import __version__
 
 extra_test = [
+    'coverage==4.*',
     'pytest>=4',
     'pytest-cov>=2',
 
@@ -50,6 +51,7 @@
         'flake8.extension': [
             'FS001 = flake8_use_fstring.percent:PercentFormatDetector',
             'FS002 = flake8_use_fstring.format:StrFormatDetector',
+            'FS003 = flake8_use_fstring.prefix:MissingPrefixDetector',
         ],
     },
 

tests/conftest.py

@@ -7,6 +7,8 @@ class TestFlake8Cmd(object):
     def __init__(self):
         self.percent_greedy = 0
         self.format_greedy = 0
+        self.enable_prefix = False
+        self.ignore_format = False
         self.expected_output = None
 
     def test(self):
@@ -19,6 +21,10 @@ def test(self):
             f'--percent-greedy={self.percent_greedy}',
             f'--format-greedy={self.format_greedy}',
         ]
+        if self.enable_prefix:
+            cmd.append('--enable-extensions=FS003')
+        if self.ignore_format:
+            cmd.append('--fstring-ignore-format')
         p = subprocess.run(
             cmd,
             stdout=subprocess.PIPE, stderr=subprocess.PIPE,

tests/example.py

@@ -15,7 +15,7 @@
 f = 3 % 2
 
 # match greedy level 0
-g = '{}'.format(123)
+g = '{val}'.format(val=123)
 
 # match greedy level 1
 h = ('x' + '{}').format(123)
@@ -36,5 +36,18 @@ def format(self):  # noqa: A003
 # false positive greedy level 2
 m = C().format()
 
+# missing prefix false positive
+n = (rf'{m}'
+     '{'
+     '}'
+     'm'
+     ''
+     '{}'
+     '{{m}}')
+
+# match missing prefix
+o = ('{n}'
+     '{{m}} {n}')
+
 # no errors below; coverage
 ''.strip()

tests/test_00.py

@@ -1,7 +1,7 @@
 def test_greedy_0(test_flake8_cmd):
     test_flake8_cmd.expected_output = b"""\
 tests/example.py:2:10: FS001 '%' operator used
-tests/example.py:18:9: FS002 '.format' used
+tests/example.py:18:12: FS002 '.format' used
 """
     test_flake8_cmd.test()
 
@@ -13,7 +13,7 @@ def test_greedy_1(test_flake8_cmd):
 tests/example.py:2:10: FS001 '%' operator used
 tests/example.py:5:18: FS001 '%' operator used
 tests/example.py:12:16: FS001 '%' operator used
-tests/example.py:18:9: FS002 '.format' used
+tests/example.py:18:12: FS002 '.format' used
 tests/example.py:21:17: FS002 '.format' used
 tests/example.py:34:13: FS002 '.format' used
 """
@@ -29,7 +29,7 @@ def test_greedy_2(test_flake8_cmd):
 tests/example.py:9:7: FS001 '%' operator used
 tests/example.py:12:16: FS001 '%' operator used
 tests/example.py:15:7: FS001 '%' operator used
-tests/example.py:18:9: FS002 '.format' used
+tests/example.py:18:12: FS002 '.format' used
 tests/example.py:21:17: FS002 '.format' used
 tests/example.py:25:6: FS002 '.format' used
 tests/example.py:34:13: FS002 '.format' used
@@ -46,6 +46,30 @@ def test_greedy_different(test_flake8_cmd):
 tests/example.py:9:7: FS001 '%' operator used
 tests/example.py:12:16: FS001 '%' operator used
 tests/example.py:15:7: FS001 '%' operator used
-tests/example.py:18:9: FS002 '.format' used
+tests/example.py:18:12: FS002 '.format' used
+"""
+    test_flake8_cmd.test()
+
+
+def test_missing_prefix(test_flake8_cmd):
+    test_flake8_cmd.enable_prefix = True
+    test_flake8_cmd.expected_output = b"""\
+tests/example.py:2:10: FS001 '%' operator used
+tests/example.py:18:12: FS002 '.format' used
+tests/example.py:49:6: FS003 f-string missing prefix
+tests/example.py:50:6: FS003 f-string missing prefix
+"""
+    test_flake8_cmd.test()
+
+
+def test_missing_prefix_ignore_format(test_flake8_cmd):
+    test_flake8_cmd.enable_prefix = True
+    test_flake8_cmd.ignore_format = True
+    test_flake8_cmd.expected_output = b"""\
+tests/example.py:2:10: FS001 '%' operator used
+tests/example.py:18:5: FS003 f-string missing prefix
+tests/example.py:18:12: FS002 '.format' used
+tests/example.py:49:6: FS003 f-string missing prefix
+tests/example.py:50:6: FS003 f-string missing prefix
 """
     test_flake8_cmd.test()