Processor

The processor replaces TODO comments in source files with GitHub issue links after issues are created.

Processor

#![allow(unused)]
fn main() {
pub struct Processor;
}

Stateless processor that operates on batches of (TodoComment, CreatedIssue) pairs. All methods are associated functions (no self).

replace_todos

#![allow(unused)]
fn main() {
pub async fn replace_todos(
    repo_root: &Path,
    replacements: &[(TodoComment, CreatedIssue)],
) -> ProcessorResult
}

Replaces TODO comments in source files with GH_ISSUE: <issue_url> links.

Behaviour:

1. Groups replacements by file path for efficient batch processing
2. For each file, validates the path stays within repo_root
3. Reads file content, replaces each TODO line, writes back atomically
4. Returns a ProcessorResult with counts and per-file errors

Path safety:

• Both the file path and repo root are canonicalised before comparison
• Files outside the repo root are rejected with PathOutsideRoot
• Issue URLs must start with https://github.com/ or are rejected

Replacement format:

The comment prefix (e.g., // , # , /* ) is preserved. The TODO text after the prefix is replaced:

// TODO: Implement caching    -->    // GH_ISSUE: https://github.com/owner/repo/issues/42
# FIXME: Handle timeout        -->    # GH_ISSUE: https://github.com/owner/repo/issues/43

Atomic writes:

Files are written via a tempfile in the same directory, then atomically persisted. This prevents partial writes if the process is interrupted.

Empty input:

If replacements is empty, returns immediately with zero counts and no I/O.

ProcessorResult

#![allow(unused)]
fn main() {
pub struct ProcessorResult {
    pub files_modified: usize,
    pub todos_replaced: usize,
    pub errors: Vec<(PathBuf, TowlProcessorError)>,
}
}

Summary of a batch replacement operation. The errors field contains per-file errors that did not abort the overall operation -- other files continue processing.

Errors

#![allow(unused)]
fn main() {
pub enum TowlProcessorError {
    FileReadError(PathBuf, std::io::Error),
    FileWriteError(PathBuf, std::io::Error),
    LineOutOfBounds { path: PathBuf, line: usize, total_lines: usize },
    CommentPrefixNotFound { path: PathBuf, line: usize },
    PathOutsideRoot { path: PathBuf, root: PathBuf },
    InvalidIssueUrl { url: String },
}
}

Example

#![allow(unused)]
fn main() {
use towl::processor::Processor;

let replacements = vec![(todo, created_issue)];
let result = Processor::replace_todos(repo_root, &replacements).await;

println!("Modified {} files, replaced {} TODOs", result.files_modified, result.todos_replaced);

for (path, err) in &result.errors {
    eprintln!("Error in {}: {}", path.display(), err);
}
}