RUF010: New rule for removing blank comments

crates/ruff/resources/test/fixtures/ruff/RUF010.py

@@ -0,0 +1,19 @@
+# Multi-line comment
+# with a blank line
+#
+# is valid
+
+print("Hello, world!")  #
+
+
+def func_1():
+    # This is a valid comment
+    print("Hello, world!")  #
+
+
+def func_2():
+    # Indented multi-line comment
+    # with a blank line
+    #
+    # is valid
+    print("Hello, world!")

crates/ruff/src/checkers/physical_lines.rs

@@ -19,6 +19,7 @@ use crate::rules::pycodestyle::rules::{
 use crate::rules::pygrep_hooks::rules::{blanket_noqa, blanket_type_ignore};
 use crate::rules::pylint;
 use crate::rules::pyupgrade::rules::unnecessary_coding_comment;
+use crate::rules::ruff::rules::blank_comment;
 use crate::settings::{flags, Settings};
 
 pub fn check_physical_lines(
@@ -34,6 +35,7 @@ pub fn check_physical_lines(
     let mut has_any_shebang = false;
 
     let enforce_blanket_noqa = settings.rules.enabled(Rule::BlanketNOQA);
+    let enforce_blank_comment = settings.rules.enabled(Rule::BlankComment);
     let enforce_shebang_not_executable = settings.rules.enabled(Rule::ShebangNotExecutable);
     let enforce_shebang_missing = settings.rules.enabled(Rule::ShebangMissingExecutableFile);
     let enforce_shebang_whitespace = settings.rules.enabled(Rule::ShebangLeadingWhitespace);
@@ -83,6 +85,10 @@ pub fn check_physical_lines(
                 blanket_noqa(&mut diagnostics, &line);
             }
 
+            if enforce_blank_comment {
+                blank_comment(&mut diagnostics, &line, settings, autofix);
+            }
+
             if enforce_shebang_missing
                 || enforce_shebang_not_executable
                 || enforce_shebang_whitespace

crates/ruff/src/codes.rs

@@ -720,6 +720,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<Rule> {
         (Ruff, "007") => Rule::PairwiseOverZipped,
         (Ruff, "008") => Rule::MutableDataclassDefault,
         (Ruff, "009") => Rule::FunctionCallInDataclassDefaultArgument,
+        (Ruff, "010") => Rule::BlankComment,
         (Ruff, "100") => Rule::UnusedNOQA,
 
         // flake8-django

crates/ruff/src/registry.rs

@@ -651,6 +651,7 @@ ruff_macros::register_rules!(
     rules::ruff::rules::AmbiguousUnicodeCharacterString,
     rules::ruff::rules::AmbiguousUnicodeCharacterDocstring,
     rules::ruff::rules::AmbiguousUnicodeCharacterComment,
+    rules::ruff::rules::BlankComment,
     rules::ruff::rules::CollectionLiteralConcatenation,
     rules::ruff::rules::AsyncioDanglingTask,
     rules::ruff::rules::UnusedNOQA,
@@ -902,6 +903,7 @@ impl Rule {
             | Rule::ShebangLeadingWhitespace
             | Rule::TrailingWhitespace
             | Rule::TabIndentation
+            | Rule::BlankComment
             | Rule::BlankLineWithWhitespace => LintSource::PhysicalLines,
             Rule::AmbiguousUnicodeCharacterComment
             | Rule::AmbiguousUnicodeCharacterDocstring

crates/ruff/src/rules/ruff/mod.rs

@@ -19,6 +19,7 @@ mod tests {
 
     #[test_case(Rule::CollectionLiteralConcatenation, Path::new("RUF005.py"); "RUF005")]
     #[test_case(Rule::AsyncioDanglingTask, Path::new("RUF006.py"); "RUF006")]
+    #[test_case(Rule::BlankComment, Path::new("RUF010.py"); "RUF010")]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff/src/rules/ruff/rules/blank_comment.rs

@@ -0,0 +1,63 @@
+use crate::registry::Rule;
+use crate::settings::{flags, Settings};
+use once_cell::sync::Lazy;
+use regex::Regex;
+use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::newlines::Line;
+use ruff_text_size::{TextLen, TextRange, TextSize};
+
+/// ## What it does
+/// Check for blank comments.
+///
+/// ## Why is this bad?
+/// Blank comments are useless and should be removed.
+///
+/// ## Example
+/// ```python
+/// print("Hello, World!")  #
+/// ```
+///
+/// Use instead:
+/// ```python
+/// print("Hello, World!")
+/// ```
+///
+/// ## References
+/// - [Ruff documentation](https://beta.ruff.rs/docs/configuration/#error-suppression)
+#[violation]
+pub struct BlankComment;
+
+impl AlwaysAutofixableViolation for BlankComment {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("Blank comments are useless and should be removed")
+    }
+
+    fn autofix_title(&self) -> String {
+        "Remove blank comment".to_string()
+    }
+}
+
+static BLACK_COMMENT_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"\S(\s*#\s*)$").unwrap());
+
+/// RUF010
+pub fn blank_comment(
+    diagnostics: &mut Vec<Diagnostic>,
+    line: &Line,
+    settings: &Settings,
+    autofix: flags::Autofix,
+) {
+    if let Some(captures) = BLACK_COMMENT_REGEX.captures(line.as_str()) {
+        let match_ = captures.get(1).unwrap();
+        let range = TextRange::at(
+            line.start() + TextSize::try_from(match_.start()).unwrap(),
+            match_.as_str().text_len(),
+        );
+        let mut diagnostic = Diagnostic::new(BlankComment, range);
+        if autofix.into() && settings.rules.should_fix(Rule::BlankComment) {
+            diagnostic.set_fix(Edit::deletion(range.start(), range.end()));
+        }
+        diagnostics.push(diagnostic);
+    }
+}

crates/ruff/src/rules/ruff/rules/mod.rs

@@ -1,5 +1,6 @@
 mod ambiguous_unicode_character;
 mod asyncio_dangling_task;
+mod blank_comment;
 mod collection_literal_concatenation;
 mod mutable_defaults_in_dataclass_fields;
 mod pairwise_over_zipped;
@@ -10,6 +11,7 @@ pub use ambiguous_unicode_character::{
     AmbiguousUnicodeCharacterDocstring, AmbiguousUnicodeCharacterString,
 };
 pub use asyncio_dangling_task::{asyncio_dangling_task, AsyncioDanglingTask};
+pub use blank_comment::{blank_comment, BlankComment};
 pub use collection_literal_concatenation::{
     collection_literal_concatenation, CollectionLiteralConcatenation,
 };

crates/ruff/src/rules/ruff/snapshots/ruff__rules__ruff__tests__RUF010_RUF010.py.snap

@@ -0,0 +1,42 @@
+---
+source: crates/ruff/src/rules/ruff/mod.rs
+---
+RUF010.py:6:23: RUF010 [*] Blank comments are useless and should be removed
+  |
+6 | # is valid
+7 | 
+8 | print("Hello, world!")  #
+  |                       ^^^ RUF010
+  |
+  = help: Remove blank comment
+
+ℹ Suggested fix
+3 3 | #
+4 4 | # is valid
+5 5 | 
+6   |-print("Hello, world!")  #
+  6 |+print("Hello, world!")
+7 7 | 
+8 8 | 
+9 9 | def func_1():
+
+RUF010.py:11:27: RUF010 [*] Blank comments are useless and should be removed
+   |
+11 | def func_1():
+12 |     # This is a valid comment
+13 |     print("Hello, world!")  #
+   |                           ^^^ RUF010
+   |
+   = help: Remove blank comment
+
+ℹ Suggested fix
+8  8  | 
+9  9  | def func_1():
+10 10 |     # This is a valid comment
+11    |-    print("Hello, world!")  #
+   11 |+    print("Hello, world!")
+12 12 | 
+13 13 | 
+14 14 | def func_2():
+
+