Optimize repository loading and enhance Git UI

Consolidate multiple Git backend calls into a single bundle to reduce
overhead when opening and auto-refreshing repositories. This significantly
improves performance by fetching status, branches, commits, and files
in one optimized operation, instead of re-running 'git rev-parse' and
'git status' multiple times.

Also, streamline commit history loading by fetching file changes inline
via 'git log --name-status -z', eliminating expensive per-commit
'git diff-tree' processes.

Additionally, introduce the ability to create new branches from a
specific commit in the history and refactor the commit comparison
feature into a dedicated dialog. The status panel now displays concise
file names.

src-tauri/src/git.rs

@@ -208,6 +208,41 @@ pub fn open_repository(path: String) -> Result<GitStatus, String> {
     status_for_repo(&repo)
 }
 
+#[derive(Debug, Clone, Serialize)]
+pub struct RepositoryBundle {
+    pub status: GitStatus,
+    pub branches: Vec<GitBranch>,
+    pub commits: Vec<GitCommit>,
+    pub files: Vec<GitRepositoryFile>,
+}
+
+/// Opens a repository and gathers everything the UI needs in a single call.
+///
+/// Runs on a blocking thread (so the UI/overlay stays responsive) and resolves
+/// the repo and its status only once, instead of the previous four separate
+/// commands that each re-ran `git rev-parse` and `git status`.
+#[tauri::command]
+pub async fn open_repository_bundle(
+    path: String,
+    commit_limit: Option<u32>,
+) -> Result<RepositoryBundle, String> {
+    tauri::async_runtime::spawn_blocking(move || -> Result<RepositoryBundle, String> {
+        let repo = resolve_repo(&path)?;
+        let status = status_for_repo(&repo)?;
+        let branches = branches_for_repo(&repo)?;
+        let commits = commits_for_repo(&repo, commit_limit)?;
+        let files = repository_files_with_status(&repo, &status)?;
+        Ok(RepositoryBundle {
+            status,
+            branches,
+            commits,
+            files,
+        })
+    })
+    .await
+    .map_err(|err| format!("Repository konnte nicht geladen werden: {err}"))?
+}
+
 #[tauri::command]
 pub fn get_status(path: String) -> Result<GitStatus, String> {
     let repo = resolve_repo(&path)?;
@@ -217,8 +252,12 @@ pub fn get_status(path: String) -> Result<GitStatus, String> {
 #[tauri::command]
 pub fn list_branches(path: String) -> Result<Vec<GitBranch>, String> {
     let repo = resolve_repo(&path)?;
+    branches_for_repo(&repo)
+}
+
+fn branches_for_repo(repo: &Path) -> Result<Vec<GitBranch>, String> {
     let output = run_git(
-        &repo,
+        repo,
         [
             "for-each-ref",
             "--format=%(refname)\t%(HEAD)",
@@ -282,10 +321,23 @@ pub fn checkout_branch(path: String, branch: String) -> Result<GitStatus, String
 }
 
 #[tauri::command]
-pub fn create_branch(path: String, branch: String) -> Result<GitStatus, String> {
+pub fn create_branch(
+    path: String,
+    branch: String,
+    start_point: Option<String>,
+) -> Result<GitStatus, String> {
     let repo = resolve_repo(&path)?;
     let branch = validate_new_branch_name(&repo, &branch)?;
-    run_git(&repo, ["checkout", "-b", branch.as_str()])?;
+    match start_point {
+        Some(start) if !start.trim().is_empty() => {
+            // Resolve the requested commit first so we fail clearly if it is gone.
+            let start = verify_commit(&repo, &start)?;
+            run_git(&repo, ["checkout", "-b", branch.as_str(), start.as_str()])?;
+        }
+        _ => {
+            run_git(&repo, ["checkout", "-b", branch.as_str()])?;
+        }
+    }
     status_for_repo(&repo)
 }
 
@@ -586,23 +638,34 @@ pub fn merge_branch(path: String, branch: String) -> Result<GitStatus, String> {
 #[tauri::command]
 pub fn list_commits(path: String, limit: Option<u32>) -> Result<Vec<GitCommit>, String> {
     let repo = resolve_repo(&path)?;
-    if verify_commit(&repo, "HEAD").is_err() {
+    commits_for_repo(&repo, limit)
+}
+
+fn commits_for_repo(repo: &Path, limit: Option<u32>) -> Result<Vec<GitCommit>, String> {
+    if verify_commit(repo, "HEAD").is_err() {
         return Ok(Vec::new());
     }
 
     let limit = limit.unwrap_or(100).clamp(1, 500).to_string();
+    // Fetch the per-commit changed files inline via `--name-status` in a single
+    // `git log` process, instead of spawning one `git diff-tree` per commit
+    // (which was ~100 extra processes and the main cost of opening a repo).
     let output = run_git(
-        &repo,
+        repo,
         [
             "log",
             "--decorate=short",
-            "--pretty=format:%H%x1f%h%x1f%an%x1f%ae%x1f%aI%x1f%D%x1f%P%x1f%s%x1e",
+            "--name-status",
+            "-M",
+            "-z",
+            "--root",
+            "--pretty=format:%x1e%H%x1f%h%x1f%an%x1f%ae%x1f%aI%x1f%D%x1f%P%x1f%s%x1f",
             "-n",
             limit.as_str(),
         ],
     )?;
 
-    parse_commit_log(&repo, &output)
+    parse_commit_log_inline(&output)
 }
 
 #[tauri::command]
@@ -1242,6 +1305,13 @@ fn status_for_repo(repo: &Path) -> Result<GitStatus, String> {
 
 fn repository_files(repo: &Path) -> Result<Vec<GitRepositoryFile>, String> {
     let status = status_for_repo(repo)?;
+    repository_files_with_status(repo, &status)
+}
+
+fn repository_files_with_status(
+    repo: &Path,
+    status: &GitStatus,
+) -> Result<Vec<GitRepositoryFile>, String> {
     let mut files = BTreeMap::<String, GitRepositoryFile>::new();
 
     let tracked_output = run_git(repo, ["ls-files", "-z", "--cached", "--deleted"])?;
@@ -1580,6 +1650,71 @@ fn commit_search_metadata(repo: &Path, commit: &str) -> Result<GitSearchCommitMe
     })
 }
 
+/// Parses `git log --name-status -z` output where each commit's changed files
+/// are embedded inline (see `commits_for_repo`), so no per-commit git process is
+/// needed. Record layout: `\x1e` then eight `\x1f`-separated header fields, then
+/// git's newline, then the NUL-separated name-status entries.
+fn parse_commit_log_inline(output: &[u8]) -> Result<Vec<GitCommit>, String> {
+    const FIELD_SEPARATOR: u8 = 0x1f;
+    const RECORD_SEPARATOR: u8 = 0x1e;
+
+    let mut commits = Vec::new();
+
+    for record in output.split(|byte| *byte == RECORD_SEPARATOR) {
+        // Skip the empty leading chunk and any stray separators left by `-z`.
+        if record
+            .iter()
+            .all(|&byte| matches!(byte, 0 | b'\n' | b'\r' | b' ' | b'\t'))
+        {
+            continue;
+        }
+
+        let parts: Vec<&[u8]> = record.splitn(9, |byte| *byte == FIELD_SEPARATOR).collect();
+        if parts.len() < 8 {
+            return Err(format!(
+                "Unerwarteter Git-Log-Eintrag: {}",
+                String::from_utf8_lossy(record)
+            ));
+        }
+
+        // Field 8 (if present) holds the name-status list, preceded by the newline
+        // git inserts between the pretty-format output and the diff.
+        let mut files_bytes: &[u8] = parts.get(8).copied().unwrap_or(&[]);
+        while let Some((&first, rest)) = files_bytes.split_first() {
+            if matches!(first, b'\n' | b'\r') {
+                files_bytes = rest;
+            } else {
+                break;
+            }
+        }
+
+        let refs = String::from_utf8_lossy(parts[5])
+            .split(',')
+            .map(str::trim)
+            .filter(|item| !item.is_empty())
+            .map(ToString::to_string)
+            .collect();
+        let parents = String::from_utf8_lossy(parts[6])
+            .split_whitespace()
+            .map(ToString::to_string)
+            .collect();
+
+        commits.push(GitCommit {
+            hash: String::from_utf8_lossy(parts[0]).trim().to_string(),
+            short_hash: String::from_utf8_lossy(parts[1]).trim().to_string(),
+            author_name: String::from_utf8_lossy(parts[2]).to_string(),
+            author_email: String::from_utf8_lossy(parts[3]).to_string(),
+            date: String::from_utf8_lossy(parts[4]).trim().to_string(),
+            refs,
+            parents,
+            summary: String::from_utf8_lossy(parts[7]).to_string(),
+            files: parse_commit_files(files_bytes)?,
+        });
+    }
+
+    Ok(commits)
+}
+
 fn parse_commit_log(repo: &Path, output: &[u8]) -> Result<Vec<GitCommit>, String> {
     const FIELD_SEPARATOR: char = '\x1f';
     const RECORD_SEPARATOR: char = '\x1e';
@@ -3234,6 +3369,7 @@ mod tests {
         let status = create_branch(
             repo.path.to_string_lossy().to_string(),
             "feature/new-panel".to_string(),
+            None,
         )
         .unwrap();
 
@@ -3246,6 +3382,7 @@ mod tests {
         let err = create_branch(
             repo.path.to_string_lossy().to_string(),
             "feature/new-panel".to_string(),
+            None,
         )
         .unwrap_err();
         assert!(err.contains("existiert bereits"));

src-tauri/src/main.rs

@@ -6,7 +6,8 @@ use git::{
     cancel_code_search, checkout_branch, commit, compare_commits, compare_file_to_head,
     compare_file_to_parent, create_branch, cred_delete, cred_load, cred_save,
     diff_file_against_working_tree, get_remote_url, get_status, list_branches, list_commits,
-    list_file_history, list_repository_files, merge_branch, open_repository, pull, push,
+    list_file_history, list_repository_files, merge_branch, open_repository,
+    open_repository_bundle, pull, push,
     read_conflict, resolve_conflict, resolve_conflict_side, restore_file_from_commit,
     restore_files, restore_to_commit, search_code_introductions, stage_files, unstage_files,
     SearchCancellationState,
@@ -34,6 +35,7 @@ fn main() {
             restore_file_from_commit,
             merge_branch,
             list_repository_files,
+            open_repository_bundle,
             list_file_history,
             compare_commits,
             compare_file_to_head,