Add imara-diff v0.2 with slider heuristics support

gix-diff/Cargo.toml

@@ -15,7 +15,20 @@ autotests = false
 [features]
 default = ["blob", "index"]
 ## Enable diffing of blobs using imara-diff.
-blob = ["dep:imara-diff", "dep:gix-filter", "dep:gix-worktree", "dep:gix-path", "dep:gix-fs", "dep:gix-command", "dep:gix-tempfile", "dep:gix-trace", "dep:gix-traverse"]
+blob = [
+    "dep:imara-diff",
+    "dep:gix-filter",
+    "dep:gix-worktree",
+    "dep:gix-path",
+    "dep:gix-fs",
+    "dep:gix-command",
+    "dep:gix-tempfile",
+    "dep:gix-trace",
+    "dep:gix-traverse"
+]
+## An experimental use of the v0.2 branch of `imara-diff` to allow trying it out, and for writing tests against it more easily.
+## We will decide later how it should actually be exposed.
+blob-experimental = ["dep:imara-diff-v2"]
 ## Enable diffing of two indices, which also allows for a generic rewrite tracking implementation.
 index = ["dep:gix-index", "dep:gix-pathspec", "dep:gix-attributes"]
 ## Data structures implement `serde::Serialize` and `serde::Deserialize`.
@@ -43,6 +56,7 @@ gix-traverse = { version = "^0.49.0", path = "../gix-traverse", optional = true
 
 thiserror = "2.0.17"
 imara-diff = { version = "0.1.8", optional = true }
+imara-diff-v2 = { version = "0.2.0", optional = true, package = "imara-diff" }
 serde = { version = "1.0.114", optional = true, default-features = false, features = ["derive"] }
 getrandom = { version = "0.2.8", optional = true, default-features = false, features = ["js"] }
 bstr = { version = "1.12.0", default-features = false }

gix-diff/src/blob/mod.rs

@@ -5,6 +5,42 @@ use std::{collections::HashMap, path::PathBuf};
 use bstr::BString;
 pub use imara_diff::*;
 
+/// Re-export imara-diff v0.2 types for use with slider heuristics.
+///
+/// This module provides access to the v0.2 API of imara-diff, which includes
+/// support for Git's slider heuristics to produce more intuitive diffs.
+#[cfg(feature = "blob-experimental")]
+pub use imara_diff_v2 as v2;
+
+/// Compute a diff with Git's slider heuristics to produce more intuitive diffs.
+///
+/// This function uses `imara-diff` v0.2 which provides the [`v2::Diff`] structure
+/// that supports postprocessing with slider heuristics. The slider heuristics move
+/// diff hunks to more intuitive locations based on indentation and other factors,
+/// resulting in diffs that are more readable and match Git's output more closely.
+///
+/// # Examples
+///
+/// ```
+/// use gix_diff::blob::{diff_with_slider_heuristics, v2::{Algorithm, InternedInput}};
+///
+/// let before = "fn foo() {\n    let x = 1;\n}\n";
+/// let after = "fn foo() {\n    let x = 2;\n}\n";
+///
+/// let input = InternedInput::new(before, after);
+/// let diff = diff_with_slider_heuristics(Algorithm::Histogram, &input);
+///
+/// // The diff now has slider heuristics applied
+/// assert_eq!(diff.count_removals(), 1);
+/// assert_eq!(diff.count_additions(), 1);
+/// ```
+#[cfg(feature = "blob-experimental")]
+pub fn diff_with_slider_heuristics<T: AsRef<[u8]>>(algorithm: v2::Algorithm, input: &v2::InternedInput<T>) -> v2::Diff {
+    let mut diff = v2::Diff::compute(algorithm, input);
+    diff.postprocess_lines(input);
+    diff
+}
+
 ///
 pub mod pipeline;
 

gix-diff/tests/Cargo.toml

@@ -17,7 +17,7 @@ name = "diff"
 path = "diff/main.rs"
 
 [dev-dependencies]
-gix-diff = { path = ".." }
+gix-diff = { path = "..", features = ["blob-experimental"] }
 gix-index = { path = "../../gix-index" }
 gix-pathspec = { path = "../../gix-pathspec" }
 gix-hash = { path = "../../gix-hash" }

gix-diff/tests/diff/blob/mod.rs

@@ -2,3 +2,4 @@ pub(crate) mod pipeline;
 mod platform;
 mod slider;
 mod unified_diff;
+mod v2;