diffguard-diff

Unified diff parser used by diffguard.

This crate parses git-style unified diffs and extracts scoped lines in diff order. It is pure parsing logic with no I/O.

What It Returns

• Vec<DiffLine> with path, line, content, and ChangeKind
• DiffStats with file/line totals

Scope behavior:

• Scope::Added - all added (+) lines
• Scope::Changed / Scope::Modified - added lines that replace removed lines
• Scope::Deleted - removed (-) lines

Main API

use diffguard_diff::{parse_unified_diff, ChangeKind};
use diffguard_types::Scope;

let diff = r#"
diff --git a/src/lib.rs b/src/lib.rs
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,1 +1,2 @@
 fn existing() {}
+fn added() {}
"#;

let (lines, stats) = parse_unified_diff(diff, Scope::Added)?;
assert_eq!(stats.files, 1);
assert_eq!(lines[0].kind, ChangeKind::Added);

Special Cases Handled

• binary file markers
• submodule diffs
• deleted files (included only for Scope::Deleted)
• mode-only changes
• renames (rename from / rename to)
• quoted/escaped git paths
• malformed hunks (skip bad hunk and continue parsing later content)

Robustness Contract

• No panics for malformed diff content
• Deterministic output ordering
• Fuzz-tested (fuzz_targets/unified_diff_parser)

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.