Remove vestigal concrete Project database, keeping trait (#198)

Author: joshuadavidthomas

Cargo.lock

@@ -8,6 +8,8 @@ extension-module = []
 default = []
 
 [dependencies]
+djls-workspace = { workspace = true }
+
 pyo3 = { workspace = true }
 salsa = { workspace = true }
 which = { workspace = true}

crates/djls-project/Cargo.toml

@@ -1,31 +1,31 @@
+//! Project-specific database trait and queries.
+//!
+//! This module extends the workspace database trait with project-specific
+//! functionality including metadata access and Python environment discovery.
+
+use djls_workspace::Db as WorkspaceDb;
+
 use crate::meta::ProjectMetadata;
+use crate::python::PythonEnvironment;
 
+/// Project-specific database trait extending the workspace database
 #[salsa::db]
-pub trait Db: salsa::Database {
+pub trait Db: WorkspaceDb {
+    /// Get the project metadata containing root path and venv configuration
     fn metadata(&self) -> &ProjectMetadata;
 }
 
-#[salsa::db]
-#[derive(Clone)]
-pub struct ProjectDatabase {
-    storage: salsa::Storage<ProjectDatabase>,
-    metadata: ProjectMetadata,
-}
-
-impl ProjectDatabase {
-    pub fn new(metadata: ProjectMetadata) -> Self {
-        let storage = salsa::Storage::new(None);
+/// Find the Python environment for the project.
+///
+/// This Salsa tracked function discovers the Python environment based on:
+/// 1. Explicit venv path from metadata
+/// 2. VIRTUAL_ENV environment variable
+/// 3. Common venv directories in project root (.venv, venv, env, .env)
+/// 4. System Python as fallback
+#[salsa::tracked]
+pub fn find_python_environment(db: &dyn Db) -> Option<PythonEnvironment> {
+    let project_path = db.metadata().root().as_path();
+    let venv_path = db.metadata().venv().and_then(|p| p.to_str());
 
-        Self { storage, metadata }
-    }
+    PythonEnvironment::new(project_path, venv_path)
 }
-
-#[salsa::db]
-impl Db for ProjectDatabase {
-    fn metadata(&self) -> &ProjectMetadata {
-        &self.metadata
-    }
-}
-
-#[salsa::db]
-impl salsa::Database for ProjectDatabase {}

crates/djls-project/src/db.rs

@@ -8,11 +8,11 @@ use std::fmt;
 use std::path::Path;
 use std::path::PathBuf;
 
-use db::ProjectDatabase;
-use meta::ProjectMetadata;
+pub use db::find_python_environment;
+pub use db::Db;
+pub use meta::ProjectMetadata;
 use pyo3::prelude::*;
-use python::find_python_environment;
-use python::PythonEnvironment;
+pub use python::PythonEnvironment;
 pub use templatetags::TemplateTags;
 
 #[derive(Debug)]
@@ -32,11 +32,9 @@ impl DjangoProject {
         }
     }
 
-    pub fn initialize(&mut self, venv_path: Option<&str>) -> PyResult<()> {
-        let venv_pathbuf = venv_path.map(PathBuf::from);
-        let metadata = ProjectMetadata::new(self.path.clone(), venv_pathbuf);
-        let db = ProjectDatabase::new(metadata);
-        self.env = find_python_environment(&db);
+    pub fn initialize(&mut self, db: &dyn Db) -> PyResult<()> {
+        // Use the database to find the Python environment
+        self.env = find_python_environment(db);
         if self.env.is_none() {
             return Err(PyErr::new::<pyo3::exceptions::PyRuntimeError, _>(
                 "Could not find Python environment",

crates/djls-project/src/lib.rs

@@ -7,14 +7,17 @@ pub struct ProjectMetadata {
 }
 
 impl ProjectMetadata {
+    #[must_use]
     pub fn new(root: PathBuf, venv: Option<PathBuf>) -> Self {
         ProjectMetadata { root, venv }
     }
 
+    #[must_use]
     pub fn root(&self) -> &PathBuf {
         &self.root
     }
 
+    #[must_use]
     pub fn venv(&self) -> Option<&PathBuf> {
         self.venv.as_ref()
     }

crates/djls-project/src/meta.rs

@@ -4,17 +4,8 @@ use std::path::PathBuf;
 
 use pyo3::prelude::*;
 
-use crate::db::Db;
 use crate::system;
 
-#[salsa::tracked]
-pub fn find_python_environment(db: &dyn Db) -> Option<PythonEnvironment> {
-    let project_path = db.metadata().root().as_path();
-    let venv_path = db.metadata().venv().and_then(|p| p.to_str());
-
-    PythonEnvironment::new(project_path, venv_path)
-}
-
 #[derive(Clone, Debug, PartialEq)]
 pub struct PythonEnvironment {
     python_path: PathBuf,
@@ -23,7 +14,8 @@ pub struct PythonEnvironment {
 }
 
 impl PythonEnvironment {
-    fn new(project_path: &Path, venv_path: Option<&str>) -> Option<Self> {
+    #[must_use]
+    pub fn new(project_path: &Path, venv_path: Option<&str>) -> Option<Self> {
         if let Some(path) = venv_path {
             let prefix = PathBuf::from(path);
             if let Some(env) = Self::from_venv_prefix(&prefix) {
@@ -703,12 +695,57 @@ mod tests {
         }
     }
 
-    // Add tests for the salsa tracked function
     mod salsa_integration {
+        use std::sync::Arc;
+
+        use djls_workspace::FileSystem;
+        use djls_workspace::InMemoryFileSystem;
+
         use super::*;
-        use crate::db::ProjectDatabase;
+        use crate::db::find_python_environment;
+        use crate::db::Db as ProjectDb;
         use crate::meta::ProjectMetadata;
 
+        /// Test implementation of ProjectDb for unit tests
+        #[salsa::db]
+        #[derive(Clone)]
+        struct TestDatabase {
+            storage: salsa::Storage<TestDatabase>,
+            metadata: ProjectMetadata,
+            fs: Arc<dyn FileSystem>,
+        }
+
+        impl TestDatabase {
+            fn new(metadata: ProjectMetadata) -> Self {
+                Self {
+                    storage: salsa::Storage::new(None),
+                    metadata,
+                    fs: Arc::new(InMemoryFileSystem::new()),
+                }
+            }
+        }
+
+        #[salsa::db]
+        impl salsa::Database for TestDatabase {}
+
+        #[salsa::db]
+        impl djls_workspace::Db for TestDatabase {
+            fn fs(&self) -> Arc<dyn FileSystem> {
+                self.fs.clone()
+            }
+
+            fn read_file_content(&self, path: &std::path::Path) -> std::io::Result<String> {
+                self.fs.read_to_string(path)
+            }
+        }
+
+        #[salsa::db]
+        impl ProjectDb for TestDatabase {
+            fn metadata(&self) -> &ProjectMetadata {
+                &self.metadata
+            }
+        }
+
         #[test]
         fn test_find_python_environment_with_salsa_db() {
             let project_dir = tempdir().unwrap();
@@ -721,8 +758,8 @@ mod tests {
             let metadata =
                 ProjectMetadata::new(project_dir.path().to_path_buf(), Some(venv_prefix.clone()));
 
-            // Create a ProjectDatabase with the metadata
-            let db = ProjectDatabase::new(metadata);
+            // Create a TestDatabase with the metadata
+            let db = TestDatabase::new(metadata);
 
             // Call the tracked function
             let env = find_python_environment(&db);
@@ -756,8 +793,8 @@ mod tests {
             // Create a metadata instance with project path but no explicit venv path
             let metadata = ProjectMetadata::new(project_dir.path().to_path_buf(), None);
 
-            // Create a ProjectDatabase with the metadata
-            let db = ProjectDatabase::new(metadata);
+            // Create a TestDatabase with the metadata
+            let db = TestDatabase::new(metadata);
 
             // Mock to ensure VIRTUAL_ENV is not set
             let _guard = system::mock::MockGuard;

crates/djls-project/src/python.rs

@@ -1,8 +1,8 @@
 //! Concrete Salsa database implementation for the Django Language Server.
 //!
 //! This module provides the concrete [`DjangoDatabase`] that implements all
-//! the database traits from workspace and template crates. This follows Ruff's
-//! architecture pattern where the concrete database lives at the top level.
+//! the database traits from workspace, template, and project crates. This follows
+//! Ruff's architecture pattern where the concrete database lives at the top level.
 
 use std::path::Path;
 use std::path::PathBuf;
@@ -11,6 +11,8 @@ use std::sync::Arc;
 use std::sync::Mutex;
 
 use dashmap::DashMap;
+use djls_project::Db as ProjectDb;
+use djls_project::ProjectMetadata;
 use djls_templates::db::Db as TemplateDb;
 use djls_workspace::db::Db as WorkspaceDb;
 use djls_workspace::db::SourceFile;
@@ -23,6 +25,7 @@ use salsa::Setter;
 /// This database implements all the traits from various crates:
 /// - [`WorkspaceDb`] for file system access and core operations
 /// - [`TemplateDb`] for template parsing and diagnostics
+/// - [`ProjectDb`] for project metadata and Python environment
 #[salsa::db]
 #[derive(Clone)]
 pub struct DjangoDatabase {
@@ -32,6 +35,9 @@ pub struct DjangoDatabase {
     /// Maps paths to [`SourceFile`] entities for O(1) lookup.
     files: Arc<DashMap<PathBuf, SourceFile>>,
 
+    /// Project metadata containing root path and venv configuration.
+    metadata: ProjectMetadata,
+
     storage: salsa::Storage<Self>,
 
     // The logs are only used for testing and demonstrating reuse:
@@ -49,6 +55,7 @@ impl Default for DjangoDatabase {
         Self {
             fs: Arc::new(InMemoryFileSystem::new()),
             files: Arc::new(DashMap::new()),
+            metadata: ProjectMetadata::new(PathBuf::from("/test"), None),
             storage: salsa::Storage::new(Some(Box::new({
                 let logs = logs.clone();
                 move |event| {
@@ -68,11 +75,16 @@ impl Default for DjangoDatabase {
 }
 
 impl DjangoDatabase {
-    /// Create a new [`DjangoDatabase`] with the given file system and file map.
-    pub fn new(file_system: Arc<dyn FileSystem>, files: Arc<DashMap<PathBuf, SourceFile>>) -> Self {
+    /// Create a new [`DjangoDatabase`] with the given file system, file map, and project metadata.
+    pub fn new(
+        file_system: Arc<dyn FileSystem>,
+        files: Arc<DashMap<PathBuf, SourceFile>>,
+        metadata: ProjectMetadata,
+    ) -> Self {
         Self {
             fs: file_system,
             files,
+            metadata,
             storage: salsa::Storage::new(None),
             #[cfg(test)]
             logs: Arc::new(Mutex::new(None)),
@@ -149,3 +161,10 @@ impl WorkspaceDb for DjangoDatabase {
 
 #[salsa::db]
 impl TemplateDb for DjangoDatabase {}
+
+#[salsa::db]
+impl ProjectDb for DjangoDatabase {
+    fn metadata(&self) -> &ProjectMetadata {
+        &self.metadata
+    }
+}

crates/djls-server/src/db.rs

@@ -149,12 +149,7 @@ impl LanguageServer for DjangoLanguageServer {
 
                 let init_result = {
                     let mut session_lock = session_arc.lock().await;
-                    if let Some(project) = session_lock.project_mut().as_mut() {
-                        project.initialize(venv_path.as_deref())
-                    } else {
-                        // Project was removed between read and write locks
-                        Ok(())
-                    }
+                    session_lock.initialize_project()
                 };
 
                 match init_result {

crates/djls-server/src/server.rs

@@ -9,11 +9,13 @@ use std::sync::Arc;
 use dashmap::DashMap;
 use djls_conf::Settings;
 use djls_project::DjangoProject;
+use djls_project::ProjectMetadata;
 use djls_workspace::db::SourceFile;
 use djls_workspace::paths;
 use djls_workspace::PositionEncoding;
 use djls_workspace::TextDocument;
 use djls_workspace::Workspace;
+use pyo3::PyResult;
 use tower_lsp_server::lsp_types;
 use url::Url;
 
@@ -63,23 +65,29 @@ impl Session {
                 std::env::current_dir().ok()
             });
 
-        let (project, settings) = if let Some(path) = &project_path {
+        let (project, settings, metadata) = if let Some(path) = &project_path {
             let settings =
                 djls_conf::Settings::new(path).unwrap_or_else(|_| djls_conf::Settings::default());
 
             let project = Some(djls_project::DjangoProject::new(path.clone()));
 
-            (project, settings)
+            // Create metadata for the project with venv path from settings
+            let venv_path = settings.venv_path().map(PathBuf::from);
+            let metadata = ProjectMetadata::new(path.clone(), venv_path);
+
+            (project, settings, metadata)
         } else {
-            (None, Settings::default())
+            // Default metadata for when there's no project path
+            let metadata = ProjectMetadata::new(PathBuf::from("."), None);
+            (None, Settings::default(), metadata)
         };
 
         // Create workspace for buffer management
         let workspace = Workspace::new();
 
-        // Create the concrete database with the workspace's file system
+        // Create the concrete database with the workspace's file system and metadata
         let files = Arc::new(DashMap::new());
-        let db = DjangoDatabase::new(workspace.file_system(), files);
+        let db = DjangoDatabase::new(workspace.file_system(), files, metadata);
 
         Self {
             db,
@@ -130,6 +138,20 @@ impl Session {
         f(&mut self.db)
     }
 
+    /// Get a reference to the database for project operations.
+    pub fn database(&self) -> &DjangoDatabase {
+        &self.db
+    }
+
+    /// Initialize the project with the database.
+    pub fn initialize_project(&mut self) -> PyResult<()> {
+        if let Some(project) = self.project.as_mut() {
+            project.initialize(&self.db)
+        } else {
+            Ok(())
+        }
+    }
+
     /// Open a document in the session.
     ///
     /// Updates both the workspace buffers and database. Creates the file in