Add world CLI compatibility for Git, xargs, devices and tool aliases

userland/git/src/changes.rs

@@ -618,6 +618,113 @@ fn unified(a: &str, b: &str, context: usize) -> String {
     out
 }
 
+/// Git's default whitespace checks apply only to added lines.
+pub fn check(
+    repo: &gix::Repository,
+    diffs: &[FileDiff],
+    revision: Option<&str>,
+    cached: bool,
+) -> Result<i32> {
+    let snapshot = if let Some(rev) = revision {
+        Some(tree(repo, rev)?)
+    } else if cached {
+        Some(index(repo)?.0)
+    } else {
+        None
+    };
+    let mut failed = false;
+    for diff in diffs.iter().filter(|diff| !diff.binary) {
+        let mut number = 0;
+        let mut added = BTreeSet::new();
+        for line in diff.patch.split_terminator('\n') {
+            if line.starts_with("@@ ") {
+                number = line
+                    .split_whitespace()
+                    .nth(2)
+                    .unwrap()
+                    .trim_start_matches('+')
+                    .split(',')
+                    .next()
+                    .unwrap()
+                    .parse::<usize>()
+                    .unwrap();
+            } else if number > 0 && line.starts_with('+') {
+                let text = &line[1..];
+                if text.trim_ascii().is_empty() {
+                    added.insert(number);
+                }
+                let indent = text
+                    .chars()
+                    .take_while(|ch| *ch == ' ' || *ch == '\t')
+                    .collect::<String>();
+                let mut errors = Vec::new();
+                if text.ends_with(|ch: char| ch.is_ascii_whitespace()) {
+                    errors.push("trailing whitespace");
+                }
+                if !text.trim_ascii().is_empty() && indent.contains(" \t") {
+                    errors.push("space before tab in indent");
+                }
+                if text.starts_with("<<<<<<< ") || text == "=======" || text.starts_with(">>>>>>> ")
+                {
+                    println!("{}:{number}: leftover conflict marker", diff.path);
+                    failed = true;
+                }
+                if !errors.is_empty() {
+                    println!("{}:{number}: {}.", diff.path, errors.join(", "));
+                    println!("{line}");
+                    failed = true;
+                }
+                number += 1;
+            } else if number > 0 && line.starts_with(' ') {
+                number += 1;
+            }
+        }
+        if added.is_empty() {
+            continue;
+        }
+        let bytes = if let Some(ref snapshot) = snapshot {
+            blob(repo, snapshot.get(diff.path.as_bytes()))?
+        } else if diff.status == Kind::Deleted {
+            Vec::new()
+        } else {
+            let file = repo.workdir().unwrap().join(&diff.path);
+            if std::fs::symlink_metadata(&file)
+                .map_err(|e| error("diff check", e))?
+                .file_type()
+                .is_symlink()
+            {
+                gix::path::into_bstr(std::fs::read_link(&file).map_err(|e| error("diff check", e))?)
+                    .map_err(|e| error("diff check", e))?
+                    .into_owned()
+                    .to_vec()
+            } else {
+                std::fs::read(file).map_err(|e| error("diff check", e))?
+            }
+        };
+        let text = String::from_utf8_lossy(&bytes);
+        let mut lines: Vec<_> = text.lines().collect();
+        if !text.ends_with('\n')
+            && lines
+                .last()
+                .is_some_and(|line| line.trim_ascii().is_empty())
+        {
+            lines.pop();
+        }
+        let first = lines
+            .iter()
+            .enumerate()
+            .rev()
+            .take_while(|(_, line)| line.trim_ascii().is_empty())
+            .filter_map(|(i, _)| added.contains(&(i + 1)).then_some(i + 1))
+            .min();
+        if let Some(line) = first {
+            println!("{}:{line}: new blank line at EOF.", diff.path);
+            failed = true;
+        }
+    }
+    Ok(if failed { 2 } else { 0 })
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;