Add --show-root flag to print resolved project root

Author: martintrojer

src/cli.rs

@@ -15,7 +15,7 @@ pub enum ColorChoice {
 )]
 pub struct Args {
     /// The search query (natural language or code snippet).
-    #[arg(required_unless_present_any = ["reindex", "stats", "clear_cache", "index_only", "type_list", "interactive", "serve"])]
+    #[arg(required_unless_present_any = ["reindex", "stats", "clear_cache", "index_only", "type_list", "interactive", "serve", "show_root"])]
     pub query: Option<String>,
 
     /// Paths to search (files or directories). Defaults to current directory.
@@ -124,6 +124,10 @@ pub struct Args {
     #[arg(long, default_value_t = 1000)]
     pub index_warn_threshold: usize,
 
+    /// Print the resolved project root and exit.
+    #[arg(long)]
+    pub show_root: bool,
+
     /// Start HTTP server mode.
     #[arg(long)]
     pub serve: bool,

src/main.rs

@@ -148,6 +148,15 @@ fn run() -> Result<bool> {
 
     // Find project root and compute path relationships
     let project_root = find_project_root(&index_root);
+
+    // Handle --show-root (no model or index needed)
+    if args.show_root {
+        let canon = project_root
+            .canonicalize()
+            .unwrap_or_else(|_| project_root.clone());
+        println!("{}", canon.display());
+        return Ok(true);
+    }
     let project_root_canon = project_root
         .canonicalize()
         .unwrap_or_else(|_| project_root.clone());

tests/integration.rs

@@ -142,3 +142,57 @@ fn test_incremental_indexing() {
     let new_hash = index.get_file_hash("a.rs").unwrap();
     assert_eq!(new_hash, Some("hash_a_v2".to_string()));
 }
+
+// --- CLI flag tests using the binary ---
+
+#[test]
+fn test_show_root_at_git_root() {
+    let dir = tempfile::TempDir::new().unwrap();
+    std::fs::create_dir(dir.path().join(".git")).unwrap();
+
+    let output = std::process::Command::new(env!("CARGO_BIN_EXE_vecgrep"))
+        .arg("--show-root")
+        .current_dir(dir.path())
+        .output()
+        .unwrap();
+
+    assert!(output.status.success());
+    let stdout = String::from_utf8(output.stdout).unwrap();
+    let expected = dir.path().canonicalize().unwrap();
+    assert_eq!(stdout.trim(), expected.display().to_string());
+}
+
+#[test]
+fn test_show_root_from_subdirectory() {
+    let dir = tempfile::TempDir::new().unwrap();
+    std::fs::create_dir(dir.path().join(".git")).unwrap();
+    std::fs::create_dir_all(dir.path().join("src/deep")).unwrap();
+
+    let output = std::process::Command::new(env!("CARGO_BIN_EXE_vecgrep"))
+        .arg("--show-root")
+        .current_dir(dir.path().join("src/deep"))
+        .output()
+        .unwrap();
+
+    assert!(output.status.success());
+    let stdout = String::from_utf8(output.stdout).unwrap();
+    let expected = dir.path().canonicalize().unwrap();
+    assert_eq!(stdout.trim(), expected.display().to_string());
+}
+
+#[test]
+fn test_show_root_no_marker_falls_back_to_cwd() {
+    let dir = tempfile::TempDir::new().unwrap();
+    // No .git, .hg, .jj, or .vecgrep — falls back to cwd
+
+    let output = std::process::Command::new(env!("CARGO_BIN_EXE_vecgrep"))
+        .arg("--show-root")
+        .current_dir(dir.path())
+        .output()
+        .unwrap();
+
+    assert!(output.status.success());
+    let stdout = String::from_utf8(output.stdout).unwrap();
+    let expected = dir.path().canonicalize().unwrap();
+    assert_eq!(stdout.trim(), expected.display().to_string());
+}