complete-merge

Finish the entire merge implementation and cover everything with tests.

Author: Byron

Cargo.lock

@@ -340,10 +340,11 @@ Check out the [performance discussion][gix-diff-performance] as well.
 
 * [x] three-way merge analysis of **blobs** with choice of how to resolve conflicts
     - [ ] choose how to resolve conflicts on the data-structure
-    - [ ] produce a new blob based on data-structure containing possible resolutions
+    - [x] produce a new blob based on data-structure containing possible resolutions
         - [x] `merge` style
         - [x] `diff3` style
         - [x] `zdiff` style
+    - [ ] various newlines-related options during the merge (see https://git-scm.com/docs/git-merge#Documentation/git-merge.txt-ignore-space-change).
     - [ ] a way to control inter-hunk merging based on proximity (maybe via `gix-diff` feature which could use the same)
 * [ ] diff-heuristics match Git perfectly
 * [x] API documentation

crate-status.md

@@ -43,6 +43,8 @@ document-features = { version = "0.2.0", optional = true }
 [dev-dependencies]
 gix-testtools = { path = "../tests/tools" }
 gix-odb = { path = "../gix-odb" }
+gix-utils = { version = "^0.1.12", path = "../gix-utils" }
+termtree = "0.5.1"
 pretty_assertions = "1.4.0"
 
 [package.metadata.docs.rs]

gix-merge/Cargo.toml

@@ -18,16 +18,16 @@ pub enum Error {
 }
 
 /// A way to configure [`commit()`](crate::commit()).
-#[derive(Default, Debug, Copy, Clone)]
+#[derive(Default, Debug, Clone)]
 pub struct Options {
     /// If `true`, merging unrelated commits is allowed, with the merge-base being assumed as empty tree.
     pub allow_missing_merge_base: bool,
     /// Options to define how trees should be merged.
     pub tree_merge: crate::tree::Options,
-    /// Options to define how to merge blobs.
-    ///
-    /// Note that these are temporarily overwritten if multiple merge-bases are merged into one.
-    pub blob_merge: crate::blob::platform::merge::Options,
+    /// If `true`, do not merge multiple merge-bases into one. Instead, just use the first one.
+    // TODO: test
+    #[doc(alias = "no_recursive", alias = "git2")]
+    pub use_first_merge_base: bool,
 }
 
 pub(super) mod function {
@@ -51,21 +51,33 @@ pub(super) mod function {
     ///
     /// Note that `objects` *should* have an object cache to greatly accelerate tree-retrieval.
     #[allow(clippy::too_many_arguments)]
-    pub fn commit<'objects>(
+    pub fn commit<'objects, E>(
         our_commit: gix_hash::ObjectId,
         their_commit: gix_hash::ObjectId,
         mut labels: crate::blob::builtin_driver::text::Labels<'_>,
         graph: &mut gix_revwalk::Graph<'_, '_, gix_revwalk::graph::Commit<gix_revision::merge_base::Flags>>,
         diff_resource_cache: &mut gix_diff::blob::Platform,
         blob_merge: &mut crate::blob::Platform,
         objects: &'objects impl gix_object::FindObjectOrHeader,
+        write_blob_to_odb: impl FnMut(&[u8]) -> Result<gix_hash::ObjectId, E>,
         options: Options,
-    ) -> Result<crate::tree::Outcome<'objects>, Error> {
+    ) -> Result<crate::tree::Outcome<'objects>, Error>
+    where
+        E: Into<Box<dyn std::error::Error + Send + Sync + 'static>>,
+    {
         let merge_bases_commit_ids = gix_revision::merge_base(our_commit, &[their_commit], graph)?;
-        let (merge_base_commit_id, ancestor_name) = match merge_bases_commit_ids {
-            Some(base_commit) if base_commit.len() == 1 => (base_commit[0], None),
+        let mut state = gix_diff::tree::State::default();
+        let (merge_base_tree_id, ancestor_name) = match merge_bases_commit_ids {
+            Some(base_commit) if base_commit.len() == 1 => {
+                (objects.find_commit(&base_commit[0], &mut state.buf1)?.tree(), None)
+            }
             Some(base_commits) => {
-                let virtual_base_tree = *base_commits.first().expect("TODO: merge multiple bases into one");
+                let virtual_base_tree = if options.use_first_merge_base {
+                    let first = *base_commits.first().expect("TODO: merge multiple bases into one");
+                    objects.find_commit(&first, &mut state.buf1)?.tree()
+                } else {
+                    todo!("merge multiple merge bases")
+                };
                 (virtual_base_tree, Some("merged common ancestors".into()))
             }
             None => {
@@ -86,8 +98,6 @@ pub(super) mod function {
             labels.ancestor = ancestor_name;
         }
 
-        let mut state = gix_diff::tree::State::default();
-        let merge_base_tree_id = objects.find_commit(&merge_base_commit_id, &mut state.buf1)?.tree();
         let our_tree_id = objects.find_commit(&our_commit, &mut state.buf1)?.tree();
         let their_tree_id = objects.find_commit(&their_commit, &mut state.buf1)?.tree();
 
@@ -97,6 +107,7 @@ pub(super) mod function {
             &their_tree_id,
             labels,
             objects,
+            write_blob_to_odb,
             &mut state,
             diff_resource_cache,
             blob_merge,