rumdl_lib/rules/
md021_no_multiple_space_closed_atx.rs

1/// Rule MD021: No multiple spaces inside closed ATX heading
2///
3/// See [docs/md021.md](../../docs/md021.md) for full documentation, configuration, and examples.
4use crate::rule::{Fix, LintError, LintResult, LintWarning, Rule, RuleCategory, Severity};
5use crate::utils::range_utils::calculate_line_range;
6use crate::utils::regex_cache::get_cached_regex;
7
8// Regex patterns
9const CLOSED_ATX_MULTIPLE_SPACE_PATTERN_STR: &str = r"^(\s*)(#+)(\s+)(.*?)(\s+)(#+)\s*$";
10
11#[derive(Clone)]
12pub struct MD021NoMultipleSpaceClosedAtx;
13
14impl Default for MD021NoMultipleSpaceClosedAtx {
15    fn default() -> Self {
16        Self::new()
17    }
18}
19
20impl MD021NoMultipleSpaceClosedAtx {
21    pub fn new() -> Self {
22        Self
23    }
24
25    fn is_closed_atx_heading_with_multiple_spaces(&self, line: &str) -> bool {
26        if let Some(captures) = get_cached_regex(CLOSED_ATX_MULTIPLE_SPACE_PATTERN_STR)
27            .ok()
28            .and_then(|re| re.captures(line))
29        {
30            let start_spaces = captures.get(3).unwrap().as_str().len();
31            let end_spaces = captures.get(5).unwrap().as_str().len();
32            start_spaces > 1 || end_spaces > 1
33        } else {
34            false
35        }
36    }
37
38    fn fix_closed_atx_heading(&self, line: &str) -> String {
39        if let Some(captures) = get_cached_regex(CLOSED_ATX_MULTIPLE_SPACE_PATTERN_STR)
40            .ok()
41            .and_then(|re| re.captures(line))
42        {
43            let indentation = &captures[1];
44            let opening_hashes = &captures[2];
45            let content = &captures[4];
46            let closing_hashes = &captures[6];
47            format!(
48                "{}{} {} {}",
49                indentation,
50                opening_hashes,
51                content.trim(),
52                closing_hashes
53            )
54        } else {
55            line.to_string()
56        }
57    }
58
59    fn count_spaces(&self, line: &str) -> (usize, usize) {
60        if let Some(captures) = get_cached_regex(CLOSED_ATX_MULTIPLE_SPACE_PATTERN_STR)
61            .ok()
62            .and_then(|re| re.captures(line))
63        {
64            let start_spaces = captures.get(3).unwrap().as_str().len();
65            let end_spaces = captures.get(5).unwrap().as_str().len();
66            (start_spaces, end_spaces)
67        } else {
68            (0, 0)
69        }
70    }
71}
72
73impl Rule for MD021NoMultipleSpaceClosedAtx {
74    fn name(&self) -> &'static str {
75        "MD021"
76    }
77
78    fn description(&self) -> &'static str {
79        "Multiple spaces inside hashes on closed heading"
80    }
81
82    fn check(&self, ctx: &crate::lint_context::LintContext) -> LintResult {
83        let mut warnings = Vec::new();
84
85        // Check all closed ATX headings from cached info
86        for (line_num, line_info) in ctx.lines.iter().enumerate() {
87            if let Some(heading) = &line_info.heading {
88                // Skip headings indented 4+ spaces (they're code blocks)
89                if line_info.visual_indent >= 4 {
90                    continue;
91                }
92
93                // Only check closed ATX headings
94                if matches!(heading.style, crate::lint_context::HeadingStyle::ATX) && heading.has_closing_sequence {
95                    let line = line_info.content(ctx.content);
96
97                    // Check if line matches closed ATX pattern with multiple spaces
98                    if self.is_closed_atx_heading_with_multiple_spaces(line) {
99                        let captures = get_cached_regex(CLOSED_ATX_MULTIPLE_SPACE_PATTERN_STR)
100                            .ok()
101                            .and_then(|re| re.captures(line))
102                            .unwrap();
103                        let _indentation = captures.get(1).unwrap();
104                        let opening_hashes = captures.get(2).unwrap();
105                        let (start_spaces, end_spaces) = self.count_spaces(line);
106
107                        let message = if start_spaces > 1 && end_spaces > 1 {
108                            format!(
109                                "Multiple spaces ({} at start, {} at end) inside hashes on closed heading (with {} at start and end)",
110                                start_spaces,
111                                end_spaces,
112                                "#".repeat(opening_hashes.as_str().len())
113                            )
114                        } else if start_spaces > 1 {
115                            format!(
116                                "Multiple spaces ({}) after {} at start of closed heading",
117                                start_spaces,
118                                "#".repeat(opening_hashes.as_str().len())
119                            )
120                        } else {
121                            format!(
122                                "Multiple spaces ({}) before {} at end of closed heading",
123                                end_spaces,
124                                "#".repeat(opening_hashes.as_str().len())
125                            )
126                        };
127
128                        // Replace the entire line with the fixed version
129                        let (start_line, start_col, end_line, end_col) = calculate_line_range(line_num + 1, line);
130                        let replacement = self.fix_closed_atx_heading(line);
131
132                        warnings.push(LintWarning {
133                            rule_name: Some(self.name().to_string()),
134                            message,
135                            line: start_line,
136                            column: start_col,
137                            end_line,
138                            end_column: end_col,
139                            severity: Severity::Warning,
140                            fix: Some(Fix {
141                                range: ctx
142                                    .line_index
143                                    .line_col_to_byte_range_with_length(start_line, 1, line.len()),
144                                replacement,
145                            }),
146                        });
147                    }
148                }
149            }
150        }
151
152        Ok(warnings)
153    }
154
155    fn fix(&self, ctx: &crate::lint_context::LintContext) -> Result<String, LintError> {
156        if self.should_skip(ctx) {
157            return Ok(ctx.content.to_string());
158        }
159        let warnings = self.check(ctx)?;
160        if warnings.is_empty() {
161            return Ok(ctx.content.to_string());
162        }
163        let warnings =
164            crate::utils::fix_utils::filter_warnings_by_inline_config(warnings, ctx.inline_config(), self.name());
165        crate::utils::fix_utils::apply_warning_fixes(ctx.content, &warnings).map_err(LintError::InvalidInput)
166    }
167
168    /// Get the category of this rule for selective processing
169    fn category(&self) -> RuleCategory {
170        RuleCategory::Heading
171    }
172
173    /// Check if this rule should be skipped
174    fn should_skip(&self, ctx: &crate::lint_context::LintContext) -> bool {
175        ctx.content.is_empty() || !ctx.likely_has_headings()
176    }
177
178    fn as_any(&self) -> &dyn std::any::Any {
179        self
180    }
181
182    fn from_config(_config: &crate::config::Config) -> Box<dyn Rule>
183    where
184        Self: Sized,
185    {
186        Box::new(MD021NoMultipleSpaceClosedAtx::new())
187    }
188}
189
190#[cfg(test)]
191mod tests {
192    use super::*;
193    use crate::lint_context::LintContext;
194
195    #[test]
196    fn test_basic_functionality() {
197        let rule = MD021NoMultipleSpaceClosedAtx;
198
199        // Test with correct spacing
200        let content = "# Heading 1 #\n## Heading 2 ##\n### Heading 3 ###";
201        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
202        let result = rule.check(&ctx).unwrap();
203        assert!(result.is_empty());
204
205        // Test with multiple spaces
206        let content = "#  Heading 1 #\n## Heading 2 ##\n### Heading 3  ###";
207        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
208        let result = rule.check(&ctx).unwrap();
209        assert_eq!(result.len(), 2); // Should flag the two headings with multiple spaces
210        assert_eq!(result[0].line, 1);
211        assert_eq!(result[1].line, 3);
212    }
213}
rumdl_lib/rules/md021_no_multiple_space_closed_atx.rs

rumdl_lib/rules/
md021_no_multiple_space_closed_atx.rs
