Workspace merges can now deal with conflicting commits.

Author: Byron

crates/but-testsupport/src/lib.rs

@@ -1,14 +1,14 @@
 //! Utilities for testing.
 #![deny(missing_docs)]
 
-use std::{collections::HashMap, path::Path};
-
 use gix::{
     Repository,
     bstr::{BStr, ByteSlice},
     config::tree::Key,
 };
 pub use gix_testtools;
+use std::io::Write;
+use std::{collections::HashMap, path::Path};
 
 mod in_memory_meta;
 pub use in_memory_meta::{InMemoryRefMetadata, InMemoryRefMetadataHandle, StackState};
@@ -31,14 +31,41 @@ pub fn hunk_header(old: &str, new: &str) -> ((u32, u32), (u32, u32)) {
     (parse_header(old), parse_header(new))
 }
 
-/// While `gix` can't (or can't conveniently) do everything, let's make using `git` easier.
+/// While `gix` can't (or can't conveniently) do everything, let's make using `git` easier,
+/// by producing a command that is anchored to the `gix` repository.
+/// Call [`run()`](CommandExt::run) when done configuring its arguments.
 pub fn git(repo: &gix::Repository) -> std::process::Command {
     let mut cmd = std::process::Command::new(gix::path::env::exe_invocation());
     cmd.current_dir(repo.workdir().expect("non-bare"));
     isolate_env_std_cmd(&mut cmd);
     cmd
 }
 
+/// Run the given `script` in bash, with the `cwd` set to the `repo` worktree.
+/// Panic if the script fails.
+pub fn invoke_bash(script: &str, repo: &gix::Repository) {
+    let mut cmd = std::process::Command::new("bash");
+    cmd.current_dir(repo.workdir().expect("non-bare"));
+    isolate_env_std_cmd(&mut cmd);
+    cmd.stdin(std::process::Stdio::piped())
+        .stdout(std::process::Stdio::piped())
+        .stderr(std::process::Stdio::piped());
+    let mut child = cmd.spawn().expect("bash can be spawned");
+    child
+        .stdin
+        .as_mut()
+        .unwrap()
+        .write_all(script.as_bytes())
+        .expect("failed to write to stdin");
+    let out = child.wait_with_output().expect("can wait for output");
+    assert!(
+        out.status.success(),
+        "{cmd:?} failed: {}\n\n{}",
+        out.stdout.as_bstr(),
+        out.stderr.as_bstr()
+    );
+}
+
 /// Open a repository at `path` suitable for testing which means that:
 ///
 /// * author and committer are configured, as well as a stable time.

crates/but-workspace/src/commit.rs

@@ -365,7 +365,8 @@ pub mod merge {
     }
 
     fn peel_to_tree(commit: gix::Id) -> anyhow::Result<gix::ObjectId> {
-        Ok(commit.object()?.peel_to_tree()?.id)
+        let commit = but_core::Commit::from_id(commit)?;
+        Ok(commit.tree_id_or_auto_resolution()?.detach())
     }
 }
 

crates/but-workspace/tests/fixtures/scenario/with-conflict.sh

@@ -3,7 +3,8 @@
 set -eu -o pipefail
 
 git init
-# A repository with a normal and an artificial conflicting commit
+echo "A repository with a normal and an artificial conflicting commit" >.git/description
+
 echo content >file && git add . && git commit -m "init"
 git tag normal
 

crates/but-workspace/tests/workspace/commit.rs

@@ -1,11 +1,13 @@
 mod from_new_merge_with_metadata {
+    use crate::ref_info::with_workspace_commit::utils::{
+        named_read_only_in_memory_scenario, named_writable_scenario_with_description_and_graph,
+    };
     use bstr::ByteSlice;
-    use but_graph::init::Options;
+    use but_graph::init::{Options, Overlay};
     use but_testsupport::{visualize_commit_graph_all, visualize_tree};
     use but_workspace::WorkspaceCommit;
     use gix::prelude::ObjectIdExt;
-
-    use crate::ref_info::with_workspace_commit::utils::named_read_only_in_memory_scenario;
+    use gix::refs::Target;
 
     #[test]
     fn without_conflict_journey() -> anyhow::Result<()> {
@@ -240,9 +242,69 @@ mod from_new_merge_with_metadata {
 
     #[test]
     fn with_conflict_commits() -> anyhow::Result<()> {
-        let (repo, mut meta) = named_read_only_in_memory_scenario("with-conflict", "")?;
-        insta::assert_snapshot!(visualize_commit_graph_all(&repo)?, @r"");
-        // but_testsupport::git(&repo)
+        let (_tmp, mut graph, repo, mut meta, _description) =
+            named_writable_scenario_with_description_and_graph("with-conflict", |_| {})?;
+        insta::assert_snapshot!(visualize_commit_graph_all(&repo)?, @r"
+        * 8450331 (HEAD -> main, tag: conflicted) GitButler WIP Commit
+        * a047f81 (tag: normal) init
+        ");
+        but_testsupport::invoke_bash(
+            r#"
+            git branch tip-conflicted
+            git reset --hard @~1
+            git checkout -b unrelated
+                touch unrelated-file && git add unrelated-file && git commit -m "unrelated"
+            "#,
+            &repo,
+        );
+        insta::assert_snapshot!(visualize_commit_graph_all(&repo)?, @r"
+        * 8450331 (tag: conflicted, tip-conflicted) GitButler WIP Commit
+        | * 8ab1c4d (HEAD -> unrelated) unrelated
+        |/  
+        * a047f81 (tag: normal, main) init
+        ");
+
+        let stacks = ["tip-conflicted", "unrelated"];
+        add_stacks(&mut meta, stacks);
+
+        graph = graph.redo_traversal_with_overlay(
+            &repo,
+            &meta,
+            Overlay::default().with_references_if_new([
+                repo.find_reference("unrelated")?.inner,
+                // The workspace ref is needed so the workspace and its stacks are iterated as well.
+                // Algorithms which work with simulation also have to be mindful about this.
+                gix::refs::Reference {
+                    name: "refs/heads/gitbutler/workspace".try_into()?,
+                    target: Target::Object(repo.rev_parse_single("main")?.detach()),
+                    peeled: None,
+                },
+            ]),
+        )?;
+
+        let out =
+            WorkspaceCommit::from_new_merge_with_metadata(&to_stacks(stacks), &graph, &repo, None)?;
+        insta::assert_debug_snapshot!(out, @r#"
+        Outcome {
+            workspace_commit_id: Sha1(ed5a3012c6a4798404f5b8586588d0ede0664683),
+            stacks: [
+                Stack { tip: 8450331, name: "tip-conflicted" },
+                Stack { tip: 8ab1c4d, name: "unrelated" },
+            ],
+            missing_stacks: [],
+            conflicting_stacks: [],
+        }
+        "#);
+
+        // There it auto-resolves the commit to not merge the actual tree structure.
+        insta::assert_snapshot!(visualize_tree(
+            out.workspace_commit_id.attach(&repo).object()?.into_commit().tree_id()?
+        ), @r#"
+        8882acc
+        ├── file:100644:e69de29 ""
+        └── unrelated-file:100644:e69de29 ""
+        "#);
+
         Ok(())
     }