comment-ascii-only (PCF005)¶

Part of the PCF rule category.

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Fix is not available.

Rule must by default be explicitly selected, unless it is removed from require-explicit.

What it does¶

Reports Python comments whose source text contains literal non-ASCII characters. The rule checks standalone comments, trailing comments, shebangs, encoding cookies, type comments, and tool directives.

Only the comment token is checked. Non-ASCII characters in strings or other Python source are outside the scope of this rule, and ASCII escape spellings such as \xe9 inside comments are accepted because the comment source itself is ASCII-only.

The rule is diagnostic-only. It does not try to escape or transliterate comments because comments may be prose, machine-readable directives, or temporarily disabled code.

Why is this useful?¶

Some projects require ASCII-only source files for portability, encoding compatibility, or review consistency. Reporting non-ASCII comments makes those violations visible without guessing the intended replacement text.

Ruff compatibility¶

None.

Examples¶

Literal non-ASCII comments are reported without automatic changes:

# café
value = 1  # naïve

PCF005: Line 1: Comment contains non-ASCII character U+00E9
PCF005: Line 2: Comment contains non-ASCII character U+00EF

All comment forms are checked, including tool directives and type comments:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
value = 1  # type: inté
# noqa: café
# pylint: disable=line-too-longé

PCF005: Line 3: Comment contains non-ASCII character U+00E9
PCF005: Line 4: Comment contains non-ASCII character U+00E9
PCF005: Line 5: Comment contains non-ASCII character U+00E9

Non-ASCII characters outside comments are ignored, and comments that use ASCII-only escape spellings are unchanged:

text = "# café is string data"
# caf\xe9 is ASCII source

ASCII-only comments are unchanged:

# cafe
value = 1  # naive

Options¶

None.