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(())
     }
 
@@ -303,7 +365,7 @@ mod from_new_merge_with_metadata {
         This is a merge commit of the virtual branches in your workspace.
 
         Due to GitButler managing multiple virtual branches, you cannot switch back and
-        forth between git branches and virtual branches easily. 
+        forth between git branches and virtual branches easily.
 
         If you switch to another branch, GitButler will need to be reinitialized.
         If you commit on this branch, GitButler will throw it away.
@@ -366,7 +428,7 @@ mod from_new_merge_with_metadata {
         This is a merge commit of the virtual branches in your workspace.
 
         Due to GitButler managing multiple virtual branches, you cannot switch back and
-        forth between git branches and virtual branches easily. 
+        forth between git branches and virtual branches easily.
 
         If you switch to another branch, GitButler will need to be reinitialized.
         If you commit on this branch, GitButler will throw it away.