Add rebase option for worktrees

src/grm/cmd.rs

@@ -91,6 +91,8 @@ pub enum WorktreeAction {
     Fetch(WorktreeFetchArgs),
     #[clap(about = "Fetch refs from remotes and update local branches")]
     Pull(WorktreePullArgs),
+    #[clap(about = "Rebase worktree onto default branch")]
+    Rebase(WorktreeRebaseArgs),
 }
 
 #[derive(Parser)]
@@ -137,6 +139,14 @@ pub struct WorktreePullArgs {
     pub rebase: bool,
 }
 
+#[derive(Parser)]
+pub struct WorktreeRebaseArgs {
+    #[clap(long = "--pull", about = "Perform a pull before rebasing")]
+    pub pull: bool,
+    #[clap(long = "--rebase", about = "Perform a rebase when doing a pull")]
+    pub rebase: bool,
+}
+
 pub fn parse() -> Opts {
     Opts::parse()
 }

src/grm/main.rs

@@ -362,6 +362,76 @@ fn main() {
                         }
                     }
                 }
+                cmd::WorktreeAction::Rebase(args) => {
+                    if args.rebase && !args.pull {
+                        print_error("There is no point in using --rebase without --pull");
+                        process::exit(1);
+                    }
+                    let repo = grm::Repo::open(&cwd, true).unwrap_or_else(|error| {
+                        if error.kind == grm::RepoErrorKind::NotFound {
+                            print_error("Directory does not contain a git repository");
+                        } else {
+                            print_error(&format!("Opening repository failed: {}", error));
+                        }
+                        process::exit(1);
+                    });
+
+                    if args.pull {
+                        repo.fetchall().unwrap_or_else(|error| {
+                            print_error(&format!("Error fetching remotes: {}", error));
+                            process::exit(1);
+                        });
+                    }
+
+                    let config =
+                        grm::repo::read_worktree_root_config(&cwd).unwrap_or_else(|error| {
+                            print_error(&format!(
+                                "Failed to read worktree configuration: {}",
+                                error
+                            ));
+                            process::exit(1);
+                        });
+
+                    let worktrees = repo.get_worktrees().unwrap_or_else(|error| {
+                        print_error(&format!("Error getting worktrees: {}", error));
+                        process::exit(1);
+                    });
+
+                    for worktree in &worktrees {
+                        if args.pull {
+                            if let Some(warning) = worktree
+                                .forward_branch(args.rebase)
+                                .unwrap_or_else(|error| {
+                                    print_error(&format!(
+                                        "Error updating worktree branch: {}",
+                                        error
+                                    ));
+                                    process::exit(1);
+                                })
+                            {
+                                print_warning(&format!("{}: {}", worktree.name(), warning));
+                            }
+                        }
+                    }
+
+                    for worktree in &worktrees {
+                        if let Some(warning) =
+                            worktree
+                                .rebase_onto_default(&config)
+                                .unwrap_or_else(|error| {
+                                    print_error(&format!(
+                                        "Error rebasing worktree branch: {}",
+                                        error
+                                    ));
+                                    process::exit(1);
+                                })
+                        {
+                            print_warning(&format!("{}: {}", worktree.name(), warning));
+                        } else {
+                            print_success(&format!("{}: Done", worktree.name()));
+                        }
+                    }
+                }
             }
         }
     }

src/repo.rs

@@ -219,8 +219,16 @@ impl Worktree {
                         .map_err(convert_libgit2_error)?;
                     let committer = rebased_commit.committer();
 
-                    if rebase.commit(None, &committer, None).is_err() {
+                    // This is effectively adding all files to the index explicitly.
+                    // Normal files are already staged, but changed submodules are not.
+                    let mut index = repo.0.index().map_err(convert_libgit2_error)?;
+                    index
+                        .add_all(["."].iter(), git2::IndexAddOption::CHECK_PATHSPEC, None)
+                        .map_err(convert_libgit2_error)?;
+
+                    if let Err(error) = rebase.commit(None, &committer, None) {
                         rebase.abort().map_err(convert_libgit2_error)?;
+                        return Err(convert_libgit2_error(error));
                     }
                 }
 
@@ -251,6 +259,78 @@ impl Worktree {
         };
         Ok(None)
     }
+
+    pub fn rebase_onto_default(
+        &self,
+        config: &Option<WorktreeRootConfig>,
+    ) -> Result<Option<String>, String> {
+        let repo = Repo::open(Path::new(&self.name), false)
+            .map_err(|error| format!("Error opening worktree: {}", error))?;
+
+        let guess_default_branch = || {
+            repo.default_branch()
+                .map_err(|_| "Could not determine default branch")?
+                .name()
+                .map_err(|error| format!("Failed getting default branch name: {}", error))
+        };
+
+        let default_branch_name = match &config {
+            None => guess_default_branch()?,
+            Some(config) => match &config.persistent_branches {
+                None => guess_default_branch()?,
+                Some(persistent_branches) => {
+                    if persistent_branches.is_empty() {
+                        guess_default_branch()?
+                    } else {
+                        persistent_branches[0].clone()
+                    }
+                }
+            },
+        };
+
+        let base_branch = repo.find_local_branch(&default_branch_name)?;
+        let base_annotated_commit = repo
+            .0
+            .find_annotated_commit(base_branch.commit()?.id().0)
+            .map_err(convert_libgit2_error)?;
+
+        let mut rebase = repo
+            .0
+            .rebase(
+                None, // use HEAD
+                Some(&base_annotated_commit),
+                None, // figure out the base yourself, libgit2!
+                Some(&mut git2::RebaseOptions::new()),
+            )
+            .map_err(convert_libgit2_error)?;
+
+        while let Some(operation) = rebase.next() {
+            let operation = operation.map_err(convert_libgit2_error)?;
+
+            // This is required to preserve the commiter of the rebased
+            // commits, which is the expected behaviour.
+            let rebased_commit = repo
+                .0
+                .find_commit(operation.id())
+                .map_err(convert_libgit2_error)?;
+            let committer = rebased_commit.committer();
+
+            // This is effectively adding all files to the index explicitly.
+            // Normal files are already staged, but changed submodules are not.
+            let mut index = repo.0.index().map_err(convert_libgit2_error)?;
+            index
+                .add_all(["."].iter(), git2::IndexAddOption::CHECK_PATHSPEC, None)
+                .map_err(convert_libgit2_error)?;
+
+            if let Err(error) = rebase.commit(None, &committer, None) {
+                rebase.abort().map_err(convert_libgit2_error)?;
+                return Err(convert_libgit2_error(error));
+            }
+        }
+
+        rebase.finish(None).map_err(convert_libgit2_error)?;
+        Ok(None)
+    }
 }
 
 impl RepoStatus {