Crate hunkpick 

Non-interactive git add -p alternative: pick and split unified-diff hunks by index, range, or content id.

hunkpick reads a unified diff from stdin (or a file), splits each hunk into minimal sub-hunks, and emits only the selected ones — suitable for piping into git apply --cached. The crate exposes the building blocks used by the CLI:

• parser — parse a unified diff into a model::Patch;
• select — resolve selectors (index, range, path:*, content id) and emit the chosen sub-hunks;
• split — split an original hunk at context boundaries;
• renumber — recompute new-side line numbers of a result diff;
• list — enumerate addressable sub-hunks (human-readable and JSON);
• validate — check internal consistency of a result diff;
• subhunk_id — stable content ids for sub-hunks;
• emit — render a model::Patch back to a unified diff;
• error — application errors with process exit codes.

use hunkpick::{emit, model, parser, select};

// A hunk with two changes separated by context auto-splits into two sub-hunks.
let diff = "\
--- a/f
+++ b/f
@@ -1,5 +1,5 @@
 a
-b
+B
 c
-d
+D
 e
";
let patch: model::Patch = parser::parse(diff.as_bytes())?;

// Take only the second one; the result is a diff of its own, with the new-side
// anchors recomputed so `git apply` can locate it.
let selectors = select::parse_selectors(&["2".to_string()])?;
let out = select::select(&patch, &selectors)?;

let text = String::from_utf8(emit::emit(&out)).unwrap();
assert!(text.contains("+D"));
assert!(!text.contains("+B"));

See the README for the selector grammar and command reference.

Modules

cli

Command-line surface: the argument types clap derives the CLI from, and colour resolution.

emit

Render a model::Patch back to a unified diff, byte-for-byte for git-canonical input.

error

Application errors and the process exit codes they map to.

gitenv

The environment variables that decide which repository a git child acts on. The environment variables that decide which repository a git invocation acts on.

list

Enumerate the addressable sub-hunks of a patch, human-readable or as JSON.

model

The data model of a parsed diff: model::Patch, model::FileDiff, model::Hunk.

parser

Parse a unified diff (git or plain) into a model::Patch.

renumber

Recompute the new-side line numbers of a result diff from the diff itself. New-side (+) line numbers of a result diff.

select

Resolve selectors (index, range, path:*, @id, @L) and build the result patch.

split

Split hunks: automatically at context gaps, explicitly at given lines, or down to a subset of changed lines.

subhunk_id

Stable, context-free content ids for sub-hunks (the @<id> selector form).

validate

Consistency checks for an input or result diff, plus the optional git apply --check gate.