change!: accept :3:<path> for the 'theirs' index stage, like Git does

gitoxide-core/src/repository/revision/explain.rs

@@ -197,9 +197,10 @@ impl delegate::Navigate for Explain<'_> {
             path,
             stage,
             match stage {
-                0 => "base",
-                1 => "ours",
-                2 => "theirs",
+                0 => "unconflicted",
+                1 => "base",
+                2 => "ours",
+                3 => "theirs",
                 _ => unreachable!("BUG: parser assures of that"),
             }
         )

gix-revision/src/spec/parse/delegate.rs

@@ -72,7 +72,8 @@ pub trait Navigate {
     /// or return `None` if it doesn't exist at this `stage`.
     /// Note that this implies no revision is needed and no anchor is set yet.
     ///
-    /// * `stage` ranges from 0 to 2, with 0 being the base, 1 being ours, 2 being theirs.
+    /// * `stage` ranges from 0 to 3, with 0 being unconflicted, 1 being the base, 2 being ours
+    ///   and 3 being theirs, just like the stages Git records in the index.
     /// * `path` without prefix is relative to the root of the repository, while prefixes like `./` and `../` make it
     ///   relative to the current working directory.
     fn index_lookup(&mut self, path: &BStr, stage: u8) -> Result<(), Exn>;

gix-revision/src/spec/parse/function.rs

@@ -403,6 +403,11 @@ where
                 format!("Couldn't find index '{path}' stage 2", path = path.as_bstr())
             });
         }
+        [b':', b'3', b':', path @ ..] => {
+            return consume_all(delegate.index_lookup(path.as_bstr(), 3), || {
+                format!("Couldn't find index '{path}' stage 3", path = path.as_bstr())
+            });
+        }
         [b':', path @ ..] => {
             return consume_all(delegate.index_lookup(path.as_bstr(), 0), || {
                 format!("Couldn't find index '{path}' stage 0 (implicit)", path = path.as_bstr())

gix-revision/tests/revision/spec/parse/anchor/colon_symbol.rs

@@ -87,6 +87,7 @@ fn various_valid_index_lookups_by_path_and_stage() {
         (":0:path", "path", 0),
         (":1:dir/path", "dir/path", 1),
         (":2:dir/path@{part-of-path}", "dir/path@{part-of-path}", 2),
+        (":3:dir/path", "dir/path", 3),
     ] {
         let rec = parse(spec);