V3 apply/unapply: MVP

crates/but-core/src/ref_metadata.rs

@@ -36,8 +36,27 @@ pub struct Workspace {
     pub push_remote: Option<String>,
 }
 
+impl Workspace {}
+
 /// Mutations
 impl Workspace {
+    /// Remove the named segment `branch`, which removes the whole stack if it's empty after removing a segment
+    /// of that name.
+    /// Returns `true` if it was removed or `false` if it wasn't found.
+    pub fn remove_segment(&mut self, branch: &FullNameRef) -> bool {
+        let Some((stack_idx, segment_idx)) = self.find_owner_indexes_by_name(branch) else {
+            return false;
+        };
+
+        let stack = &mut self.stacks[stack_idx];
+        stack.branches.remove(segment_idx);
+
+        if stack.branches.is_empty() {
+            self.stacks.remove(stack_idx);
+        }
+        true
+    }
+
     /// Insert `branch` as new stack if it's not yet contained in the workspace and if `order` is not `None` or push
     /// it to the end of the stack list.
     /// Note that `order` is only relevant at insertion time.
@@ -68,6 +87,28 @@ impl Workspace {
         }
         true
     }
+
+    /// Insert `branch` as new segment if it's not yet contained in the workspace,
+    /// and insert it above the given `anchor` segment name, which maybe the tip of a stack or any segment within one
+    /// Returns `true` if the ref was newly added, or `false` if it already existed, or `None` if `anchor` didn't exist.
+    pub fn insert_new_segment_above_anchor_if_not_present(
+        &mut self,
+        branch: &FullNameRef,
+        anchor: &FullNameRef,
+    ) -> Option<bool> {
+        if self.contains_ref(branch) {
+            return Some(false);
+        };
+        let (stack_idx, segment_idx) = self.find_owner_indexes_by_name(anchor)?;
+        self.stacks[stack_idx].branches.insert(
+            segment_idx,
+            WorkspaceStackBranch {
+                ref_name: branch.to_owned(),
+                archived: false,
+            },
+        );
+        Some(true)
+    }
 }
 
 /// Access

crates/but-core/tests/core/ref_metadata.rs

@@ -2,7 +2,7 @@ mod workspace {
     use but_core::ref_metadata::Workspace;
 
     #[test]
-    fn add_new_stack_if_not_present() {
+    fn add_new_stack_if_not_present_journey() {
         let mut ws = Workspace::default();
         assert_eq!(ws.stacks.len(), 0);
 
@@ -18,6 +18,100 @@ mod workspace {
         let c_ref = r("refs/heads/C");
         assert!(ws.add_or_insert_new_stack_if_not_present(c_ref, None));
         assert_eq!(ws.stack_names().collect::<Vec<_>>(), [b_ref, a_ref, c_ref]);
+
+        assert!(ws.remove_segment(a_ref));
+        assert!(ws.remove_segment(b_ref));
+        assert!(!ws.remove_segment(b_ref));
+        assert!(ws.remove_segment(c_ref));
+        assert!(!ws.remove_segment(c_ref));
+
+        // Everything should be removed.
+        insta::assert_debug_snapshot!(ws, @r"
+        Workspace {
+            ref_info: RefInfo { created_at: None, updated_at: None },
+            stacks: [],
+            target_ref: None,
+            push_remote: None,
+        }
+        ");
+    }
+
+    #[test]
+    fn insert_new_segment_above_anchor_if_not_present_journey() {
+        let mut ws = Workspace::default();
+        assert_eq!(ws.stacks.len(), 0);
+
+        let a_ref = r("refs/heads/A");
+        let b_ref = r("refs/heads/B");
+        assert_eq!(
+            ws.insert_new_segment_above_anchor_if_not_present(b_ref, a_ref),
+            None,
+            "anchor doesn't exist"
+        );
+        assert!(ws.add_or_insert_new_stack_if_not_present(a_ref, None));
+        assert_eq!(
+            ws.insert_new_segment_above_anchor_if_not_present(b_ref, a_ref),
+            Some(true),
+            "anchor existed and it was added"
+        );
+        assert_eq!(
+            ws.insert_new_segment_above_anchor_if_not_present(b_ref, a_ref),
+            Some(false),
+            "anchor existed and it was NOT added as it already existed"
+        );
+
+        let c_ref = r("refs/heads/C");
+        assert_eq!(
+            ws.insert_new_segment_above_anchor_if_not_present(c_ref, a_ref),
+            Some(true)
+        );
+
+        insta::assert_snapshot!(but_testsupport::sanitize_uuids_and_timestamps(format!("{ws:#?}")), @r#"
+        Workspace {
+            ref_info: RefInfo { created_at: None, updated_at: None },
+            stacks: [
+                WorkspaceStack {
+                    id: 1,
+                    branches: [
+                        WorkspaceStackBranch {
+                            ref_name: FullName(
+                                "refs/heads/B",
+                            ),
+                            archived: false,
+                        },
+                        WorkspaceStackBranch {
+                            ref_name: FullName(
+                                "refs/heads/C",
+                            ),
+                            archived: false,
+                        },
+                        WorkspaceStackBranch {
+                            ref_name: FullName(
+                                "refs/heads/A",
+                            ),
+                            archived: false,
+                        },
+                    ],
+                },
+            ],
+            target_ref: None,
+            push_remote: None,
+        }
+        "#);
+
+        assert!(ws.remove_segment(b_ref));
+        assert!(ws.remove_segment(a_ref));
+        assert!(ws.remove_segment(c_ref));
+
+        // Everything should be removed.
+        insta::assert_debug_snapshot!(ws, @r"
+        Workspace {
+            ref_info: RefInfo { created_at: None, updated_at: None },
+            stacks: [],
+            target_ref: None,
+            push_remote: None,
+        }
+        ");
     }
 
     fn r(name: &str) -> &gix::refs::FullNameRef {

crates/but-testing/src/args.rs

@@ -36,6 +36,14 @@ pub struct Args {
 
 #[derive(Debug, clap::Subcommand)]
 pub enum Subcommands {
+    /// Make an existing branch appear in the workspace.
+    Apply {
+        /// The 0-based place in the worktree into which the branch should be inserted.
+        #[clap(long, short = 'o')]
+        order: Option<usize>,
+        /// The name of the branch to apply to the workspace, like `feature` or `origin/other`.
+        branch_name: String,
+    },
     /// Add the given Git repository as project for use with GitButler.
     AddProject {
         /// The long name of the remote reference to track, like `refs/remotes/origin/main`,

crates/but-testing/src/command/mod.rs

@@ -3,6 +3,9 @@ use but_core::UnifiedDiff;
 use but_db::poll::ItemKind;
 use but_graph::VirtualBranchesTomlMetadata;
 use but_settings::AppSettings;
+use but_workspace::branch::OnWorkspaceMergeConflict;
+use but_workspace::branch::apply::{IntegrationMode, WorkspaceReferenceNaming};
+use but_workspace::branch::checkout::UncommitedWorktreeChanges;
 use but_workspace::branch::create_reference::{Anchor, Position};
 use but_workspace::{DiffSpec, HunkHeader};
 use gitbutler_project::{Project, ProjectId};
@@ -634,6 +637,32 @@ pub fn remove_reference(
     Ok(())
 }
 
+pub fn apply(args: &super::Args, short_name: &str, order: Option<usize>) -> anyhow::Result<()> {
+    let (repo, project, graph, mut meta) =
+        repo_and_maybe_project_and_graph(args, RepositoryOpenMode::Merge)?;
+    let branch = repo.find_reference(short_name)?;
+    let ws = graph.to_workspace()?;
+    _ = but_workspace::branch::apply(
+        branch.name(),
+        &ws,
+        &repo,
+        &mut *meta,
+        but_workspace::branch::apply::Options {
+            integration_mode: IntegrationMode::AlwaysMerge,
+            on_workspace_conflict: OnWorkspaceMergeConflict::MaterializeAndReportConflictingStacks,
+            workspace_reference_naming: WorkspaceReferenceNaming::Default,
+            uncommitted_changes: UncommitedWorktreeChanges::KeepAndAbortOnConflict,
+            order,
+        },
+    )?;
+
+    if project.is_some() {
+        // write metadata if there are projects - this is a special case while we use vb.toml.
+        ManuallyDrop::into_inner(meta);
+    }
+    Ok(())
+}
+
 pub fn create_reference(
     args: &super::Args,
     short_name: &str,

crates/but-testing/src/main.rs

@@ -7,6 +7,7 @@ use command::parse_diff_spec;
 use gix::bstr::BString;
 
 mod args;
+use crate::args::Subcommands;
 use crate::command::{RepositoryOpenMode, repo_and_maybe_project};
 use args::Args;
 
@@ -31,6 +32,7 @@ async fn main() -> Result<()> {
     }
 
     match &args.cmd {
+        Subcommands::Apply { branch_name, order } => command::apply(&args, branch_name, *order),
         args::Subcommands::AddProject {
             switch_to_workspace,
             path,
@@ -39,7 +41,6 @@ async fn main() -> Result<()> {
             path.to_owned(),
             switch_to_workspace.to_owned(),
         ),
-
         args::Subcommands::RemoveReference {
             permit_empty_stacks,
             keep_metadata,