refactor: extract manpage post-processing into a function with tests

- Move manpage post-processing logic into post_process_manpage() function
- Add comprehensive unit tests for all post-processing functionality
- Improve .br macro handling to correctly fix mandoc warnings
- Tests cover TH header fixes, whitespace removal, and .br pattern fixes

Author: sylvestre

Cargo.toml

@@ -31,7 +31,7 @@ expensive_tests = []
 # "test_risky_names" == enable tests that create problematic file names (would make a network share inaccessible to Windows, breaks SVN on Mac OS, etc.)
 test_risky_names = []
 # * only build `uudoc` when `--feature uudoc` is activated
-uudoc = ["dep:clap_complete", "dep:clap_mangen", "dep:fluent-syntax", "dep:zip"]
+uudoc = ["dep:clap_complete", "dep:clap_mangen", "dep:fluent-syntax", "dep:regex", "dep:zip"]
 ## features
 ## Optional feature for stdbuf
 # "feat_external_libstdbuf" == use an external libstdbuf.so for stdbuf instead of embedding it
@@ -477,6 +477,7 @@ clap_complete = { workspace = true, optional = true }
 clap_mangen = { workspace = true, optional = true }
 clap.workspace = true
 fluent-syntax = { workspace = true, optional = true }
+regex = { workspace = true, optional = true }
 itertools.workspace = true
 phf.workspace = true
 selinux = { workspace = true, optional = true }

src/bin/uudoc.rs

@@ -6,7 +6,7 @@
 // spell-checker:ignore mangen tldr
 
 use std::{
-    collections::HashMap,
+    collections::{HashMap, HashSet},
     ffi::OsString,
     fs::File,
     io::{self, Read, Seek, Write},
@@ -18,6 +18,7 @@ use clap_complete::Shell;
 use clap_mangen::Man;
 use fluent_syntax::ast::{Entry, Message, Pattern};
 use fluent_syntax::parser;
+use regex::Regex;
 use textwrap::{fill, indent, termwidth};
 use zip::ZipArchive;
 
@@ -26,6 +27,61 @@ use uucore::Args;
 
 include!(concat!(env!("OUT_DIR"), "/uutils_map.rs"));
 
+/// Post-process a generated manpage to fix mandoc lint issues
+///
+/// This function:
+/// - Fixes the TH header by uppercasing command names and removing invalid date formats
+/// - Removes trailing whitespace from all lines
+/// - Fixes redundant .br paragraph macros that cause mandoc warnings
+fn post_process_manpage(manpage: String) -> String {
+    // Only match TH headers that have at least a command name on the same line
+    // Use [ \t] instead of \s to avoid matching newlines
+    let th_regex = Regex::new(r"(?m)^\.TH[ \t]+([^ \t\n]+)(?:[ \t]+[^\n]*)?$").unwrap();
+    let mut result = th_regex
+        .replace_all(&manpage, |caps: &regex::Captures| {
+            format!(".TH {} 1", caps[1].to_uppercase())
+        })
+        .to_string();
+
+    // Process lines: remove trailing whitespace and fix .br issues in a single pass
+    let lines: Vec<&str> = result.lines().collect();
+    let mut fixed_lines = Vec::with_capacity(lines.len());
+    let mut skip_indices = HashSet::new();
+
+    // First pass: identify lines to skip (redundant .br macros)
+    for i in 0..lines.len() {
+        let line = lines[i].trim_end();
+
+        if line == ".br" && !skip_indices.contains(&i) {
+            // Check for consecutive .br macros
+            if i > 0 && lines[i - 1].trim_end() == ".br" {
+                skip_indices.insert(i);
+            }
+            // Check for .br, empty line, .br pattern
+            else if i + 2 < lines.len()
+                && lines[i + 1].trim().is_empty()
+                && lines[i + 2].trim_end() == ".br"
+            {
+                skip_indices.insert(i + 2);
+            }
+        }
+    }
+
+    // Second pass: build the final output
+    for (i, line) in lines.iter().enumerate() {
+        if !skip_indices.contains(&i) {
+            fixed_lines.push(line.trim_end());
+        }
+    }
+
+    result = fixed_lines.join("\n");
+    if !result.ends_with('\n') {
+        result.push('\n');
+    }
+
+    result
+}
+
 /// Print usage information for uudoc
 fn usage<T: Args>(utils: &UtilityMap<T>) {
     println!("uudoc - Documentation generator for uutils coreutils");
@@ -100,63 +156,15 @@ fn gen_manpage<T: Args>(
     man.render(&mut buffer).expect("Man page generation failed");
 
     // Convert to string for processing
-    let mut manpage = String::from_utf8(buffer).expect("Invalid UTF-8 in manpage");
-
-    // Fix the TH line: remove version info from date field and uppercase the command name
-    if let Some(th_pos) = manpage.find(".TH ") {
-        if let Some(line_end) = manpage[th_pos..].find('\n') {
-            let th_line = &manpage[th_pos..th_pos + line_end];
-            // Parse the TH line parts
-            let parts: Vec<&str> = th_line.split_whitespace().collect();
-            if parts.len() >= 2 {
-                let cmd_name = parts[1].to_uppercase();
-                // Reconstruct TH line with uppercase command name and no date
-                let new_th = format!(".TH {} 1", cmd_name);
-                manpage.replace_range(th_pos..th_pos + line_end, &new_th);
-            }
-        }
-    }
+    let manpage = String::from_utf8(buffer).expect("Invalid UTF-8 in manpage");
 
-    // Remove trailing whitespace from all lines and fix .br issues
-    let lines: Vec<String> = manpage
-        .lines()
-        .map(|line| line.trim_end().to_string())
-        .collect();
-
-    // Fix .br paragraph macro issues
-    let mut fixed_lines = Vec::new();
-    let mut skip_next_br = false;
-
-    for i in 0..lines.len() {
-        let line = &lines[i];
-
-        if line == ".br" {
-            // Check for problematic patterns with .br
-            let prev_is_br = i > 0 && lines[i - 1] == ".br";
-            let next_is_empty_then_br =
-                i + 2 < lines.len() && lines[i + 1].is_empty() && lines[i + 2] == ".br";
-            let prev_is_empty_with_br = i >= 2 && lines[i - 1].is_empty() && lines[i - 2] == ".br";
-
-            // Skip redundant .br in these patterns
-            if skip_next_br || prev_is_br || next_is_empty_then_br || prev_is_empty_with_br {
-                skip_next_br = false;
-                continue;
-            }
-
-            // If this .br is followed by empty line and another .br, skip the second one
-            if next_is_empty_then_br {
-                skip_next_br = true;
-            }
-        }
-
-        fixed_lines.push(line.clone());
-    }
-
-    manpage = fixed_lines.join("\n");
-    manpage.push('\n');
+    // Post-process the manpage to fix mandoc lint issues
+    let processed_manpage = post_process_manpage(manpage);
 
     // Write the processed manpage to stdout
-    io::stdout().write_all(manpage.as_bytes()).unwrap();
+    io::stdout()
+        .write_all(processed_manpage.as_bytes())
+        .unwrap();
     io::stdout().flush().unwrap();
     process::exit(0);
 }
@@ -691,3 +699,117 @@ fn format_examples(content: String, output_markdown: bool) -> Result<String, std
     )?;
     Ok(s)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_post_process_manpage_fixes_th_header() {
+        // Test that command names are uppercased and date is removed
+        let input =
+            ".TH cat 1 \"cat (uutils coreutils) 0.7.0\"\n.SH NAME\ncat - concatenate files\n";
+        let expected = ".TH CAT 1\n.SH NAME\ncat - concatenate files\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_removes_trailing_whitespace() {
+        // Test that trailing whitespace is removed from lines
+        let input = ".TH TEST 1  \nSome text with trailing spaces   \n.SH SECTION  \n";
+        let expected = ".TH TEST 1\nSome text with trailing spaces\n.SH SECTION\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_fixes_double_br() {
+        // Test that redundant .br macros are removed
+        let input = ".TH TEST 1\n.br\n.br\nSome text\n";
+        let expected = ".TH TEST 1\n.br\nSome text\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_fixes_br_with_empty_line() {
+        // Test that .br with empty line patterns are fixed
+        let input = ".TH TEST 1\n.br\n\n.br\nSome text\n";
+        let expected = ".TH TEST 1\n.br\n\nSome text\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_preserves_single_br() {
+        // Test that single .br macros are preserved
+        let input = ".TH TEST 1\nLine 1\n.br\nLine 2\n";
+        let expected = ".TH TEST 1\nLine 1\n.br\nLine 2\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_handles_mixed_case_command() {
+        // Test that mixed case command names are uppercased
+        let input = ".TH CaT 1 \"some version info\"\nContent\n";
+        let expected = ".TH CAT 1\nContent\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_handles_no_th_header() {
+        // Test that manpages without TH headers are handled gracefully
+        let input = ".SH NAME\ntest - a test utility\n";
+        let expected = ".SH NAME\ntest - a test utility\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_complex_br_pattern() {
+        // Test complex .br patterns with multiple occurrences
+        let input =
+            ".TH TEST 1\nSection 1\n.br\n\n.br\nMiddle\n.br\n.br\nSection 2\n.br\n\n.br\nEnd\n";
+        let expected = ".TH TEST 1\nSection 1\n.br\n\nMiddle\n.br\nSection 2\n.br\n\nEnd\n";
+
+        let result = post_process_manpage(input.to_string());
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_post_process_manpage_malformed_th_header() {
+        // Test that malformed TH headers don't cause panics and are handled gracefully
+        let input1 = ".TH\nContent\n"; // Missing command name
+        let expected1 = ".TH\nContent\n";
+        let result1 = post_process_manpage(input1.to_string());
+        assert_eq!(result1, expected1);
+
+        // TH header with special characters
+        let input2 = ".TH test-cmd 1 \"version 1.0\"\nContent\n";
+        let expected2 = ".TH TEST-CMD 1\nContent\n";
+        let result2 = post_process_manpage(input2.to_string());
+        assert_eq!(result2, expected2);
+
+        // TH header at end of file without newline
+        let input3 = "Content\n.TH test 1";
+        let expected3 = "Content\n.TH TEST 1\n";
+        let result3 = post_process_manpage(input3.to_string());
+        assert_eq!(result3, expected3);
+
+        // Multiple TH headers (only first should be processed due to ^anchor)
+        let input4 = ".TH first 1\nMiddle\n.TH second 1\n";
+        let expected4 = ".TH FIRST 1\nMiddle\n.TH SECOND 1\n";
+        let result4 = post_process_manpage(input4.to_string());
+        assert_eq!(result4, expected4);
+    }
+}