From 8a019b423f5d51bcfc107da9cb50aa90eacff19d Mon Sep 17 00:00:00 2001
From: Alexis Mousset <contact@amousset.me>
Date: Fri, 31 Dec 2021 09:06:54 +0100
Subject: [PATCH] Detect workspace root using language markers (#1370)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Detect workspace root using language markers

* Avoid allocating root_markers

* Update helix-core/src/lib.rs

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

* Update helix-core/src/lib.rs

Co-authored-by: Kirawi <67773714+kirawi@users.noreply.github.com>

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>
Co-authored-by: Kirawi <67773714+kirawi@users.noreply.github.com>
---
 helix-core/src/lib.rs      | 32 ++++++++++++++++++++++++++------
 helix-lsp/src/client.rs    |  6 +++++-
 helix-lsp/src/lib.rs       |  1 +
 helix-term/src/commands.rs |  3 ++-
 languages.toml             |  2 +-
 5 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/helix-core/src/lib.rs b/helix-core/src/lib.rs
index 1c78e7c0..7fd23b97 100644
--- a/helix-core/src/lib.rs
+++ b/helix-core/src/lib.rs
@@ -39,8 +39,14 @@ pub fn find_first_non_whitespace_char(line: RopeSlice) -> Option<usize> {
     line.chars().position(|ch| !ch.is_whitespace())
 }
 
-/// Find `.git` root.
-pub fn find_root(root: Option<&str>) -> Option<std::path::PathBuf> {
+/// Find project root.
+///
+/// Order of detection:
+/// * Top-most folder containing a root marker in current git repository
+/// * Git repostory root if no marker detected
+/// * Top-most folder containing a root marker if not git repository detected
+/// * Current working directory as fallback
+pub fn find_root(root: Option<&str>, root_markers: &[String]) -> Option<std::path::PathBuf> {
     let current_dir = std::env::current_dir().expect("unable to determine current directory");
 
     let root = match root {
@@ -52,16 +58,30 @@ pub fn find_root(root: Option<&str>) -> Option<std::path::PathBuf> {
                 current_dir.join(root)
             }
         }
-        None => current_dir,
+        None => current_dir.clone(),
     };
 
+    let mut top_marker = None;
     for ancestor in root.ancestors() {
-        // TODO: also use defined roots if git isn't found
+        for marker in root_markers {
+            if ancestor.join(marker).exists() {
+                top_marker = Some(ancestor);
+                break;
+            }
+        }
+        // don't go higher than repo
         if ancestor.join(".git").is_dir() {
-            return Some(ancestor.to_path_buf());
+            // Use workspace if detected from marker
+            return Some(top_marker.unwrap_or(ancestor).to_path_buf());
         }
     }
-    None
+
+    // In absence of git repo, use workspace if detected
+    if top_marker.is_some() {
+        top_marker.map(|a| a.to_path_buf())
+    } else {
+        Some(current_dir)
+    }
 }
 
 pub fn runtime_dir() -> std::path::PathBuf {
diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index 43804daa..c80f70b5 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -31,6 +31,7 @@ pub struct Client {
     pub(crate) capabilities: OnceCell<lsp::ServerCapabilities>,
     offset_encoding: OffsetEncoding,
     config: Option<Value>,
+    root_markers: Vec<String>,
 }
 
 impl Client {
@@ -39,6 +40,7 @@ impl Client {
         cmd: &str,
         args: &[String],
         config: Option<Value>,
+        root_markers: Vec<String>,
         id: usize,
     ) -> Result<(Self, UnboundedReceiver<(usize, Call)>, Arc<Notify>)> {
         let process = Command::new(cmd)
@@ -68,6 +70,7 @@ impl Client {
             capabilities: OnceCell::new(),
             offset_encoding: OffsetEncoding::Utf8,
             config,
+            root_markers,
         };
 
         Ok((client, server_rx, initialize_notify))
@@ -225,7 +228,8 @@ impl Client {
 
     pub(crate) async fn initialize(&self) -> Result<lsp::InitializeResult> {
         // TODO: delay any requests that are triggered prior to initialize
-        let root = find_root(None).and_then(|root| lsp::Url::from_file_path(root).ok());
+        let root = find_root(None, &self.root_markers)
+            .and_then(|root| lsp::Url::from_file_path(root).ok());
 
         if self.config.is_some() {
             log::info!("Using custom LSP config: {}", self.config.as_ref().unwrap());
diff --git a/helix-lsp/src/lib.rs b/helix-lsp/src/lib.rs
index 8fb321bc..1eb1c151 100644
--- a/helix-lsp/src/lib.rs
+++ b/helix-lsp/src/lib.rs
@@ -326,6 +326,7 @@ impl Registry {
                     &config.command,
                     &config.args,
                     language_config.config.clone(),
+                    language_config.roots.clone(),
                     id,
                 )?;
                 self.incoming.push(UnboundedReceiverStream::new(incoming));
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 6259ecb2..ed728115 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -3154,7 +3154,8 @@ fn command_mode(cx: &mut Context) {
 }
 
 fn file_picker(cx: &mut Context) {
-    let root = find_root(None).unwrap_or_else(|| PathBuf::from("./"));
+    // We don't specify language markers, root will be the root of the current git repo
+    let root = find_root(None, &[]).unwrap_or_else(|| PathBuf::from("./"));
     let picker = ui::file_picker(root, &cx.editor.config);
     cx.push_layer(Box::new(picker));
 }
diff --git a/languages.toml b/languages.toml
index 3d9bac7b..f088a3aa 100644
--- a/languages.toml
+++ b/languages.toml
@@ -3,7 +3,7 @@ name = "rust"
 scope = "source.rust"
 injection-regex = "rust"
 file-types = ["rs"]
-roots = []
+roots = ["Cargo.toml", "Cargo.lock"]
 auto-format = true
 comment-token = "//"
 language-server = { command = "rust-analyzer" }