diff.print({ format: "Patch" }) strips +/-/space line origin markers

[monotykamary]

What happened

diff.print({ format: "Patch" }) returns patch output that has correct ---/+++/@@ headers but is missing the +/-/ (space) prefixes on the body lines inside hunks.

What I expected

Proper unified diff output, identical to what git diff --patch produces, where every line inside a hunk is prefixed with + (addition), - (deletion), or (space, context).

Reproduction

const { Repository } = require("@es-git/repository");
const repo = await Repository.open("/path/to/dirty-repo");
const diff = await repo.diffIndexToWorkdir();
const patch = diff.print({ format: "Patch" });
console.log(patch);

Compare the output with git diff --patch in the same repo. The hunk bodies will look like this:

es-git output (broken):

@@ -1,3 +1,3 @@
 alpha
beta
 gamma

git diff output (correct):

@@ -1,3 +1,3 @@
  alpha
-beta
+MORE
  gamma

The +/-/ prefixes are completely absent from the es-git output.

Root cause

In src/diff.rs, the print method does:

let _ = self.inner.print(format.into(), |_delta, _hunk, line| {
    if let Ok(content) = std::str::from_utf8(line.content()) {
        lines.push(content.to_string());
    }
    true
});

It uses line.content() which returns the line body without the origin character. The origin (+, -, ) is available via line.origin(). It needs to be prepended:

let _ = self.inner.print(format.into(), |_delta, _hunk, line| {
    if let Ok(content) = std::str::from_utf8(line.content()) {
        lines.push(format!("{}{}", line.origin(), content));
    }
    true
});

This affects all DiffFormat variants that go through print, not just Patch, since the callback is the same.

Impact

Consumers that parse the patch output (e.g. to render diffs in a UI) cannot distinguish additions, deletions, and context lines without the origin markers. This makes the print() method unusable for any PATCH-format output that needs to be parsed downstream.

Environment

• es-git: latest (as of 2026-06-14)
• Node.js: v22.x
• OS: macOS 15