Add a slash command for automatically retrieving relevant context (#17972)

* [x] put this slash command behind a feature flag until we release
embedding access to the general population
* [x] choose a name for this slash command and name the rust module to
match

Release Notes:

- N/A

---------

Co-authored-by: Jason <jason@zed.dev>
Co-authored-by: Richard <richard@zed.dev>
Co-authored-by: Jason Mancuso <7891333+jvmncs@users.noreply.github.com>
Co-authored-by: Richard Feldman <oss@rtfeldman.com>

Author: 3 people

assets/prompts/project_slash_command.hbs

@@ -0,0 +1,8 @@
+A software developer is asking a question about their project. The source files in their project have been indexed into a database of semantic text embeddings.
+Your task is to generate a list of 4 diverse search queries that can be run on this embedding database, in order to retrieve a list of code snippets
+that are relevant to the developer's question. Redundant search queries will be heavily penalized, so only include another query if it's sufficiently
+distinct from previous ones.
+
+Here is the question that's been asked, together with context that the developer has added manually:
+
+{{{context_buffer}}}

crates/assistant/src/assistant.rs

@@ -41,9 +41,10 @@ use semantic_index::{CloudEmbeddingProvider, SemanticDb};
 use serde::{Deserialize, Serialize};
 use settings::{update_settings_file, Settings, SettingsStore};
 use slash_command::{
-    auto_command, context_server_command, default_command, delta_command, diagnostics_command,
-    docs_command, fetch_command, file_command, now_command, project_command, prompt_command,
-    search_command, symbols_command, tab_command, terminal_command, workflow_command,
+    auto_command, cargo_workspace_command, context_server_command, default_command, delta_command,
+    diagnostics_command, docs_command, fetch_command, file_command, now_command, project_command,
+    prompt_command, search_command, symbols_command, tab_command, terminal_command,
+    workflow_command,
 };
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -384,20 +385,33 @@ fn register_slash_commands(prompt_builder: Option<Arc<PromptBuilder>>, cx: &mut
     slash_command_registry.register_command(delta_command::DeltaSlashCommand, true);
     slash_command_registry.register_command(symbols_command::OutlineSlashCommand, true);
     slash_command_registry.register_command(tab_command::TabSlashCommand, true);
-    slash_command_registry.register_command(project_command::ProjectSlashCommand, true);
+    slash_command_registry
+        .register_command(cargo_workspace_command::CargoWorkspaceSlashCommand, true);
     slash_command_registry.register_command(prompt_command::PromptSlashCommand, true);
     slash_command_registry.register_command(default_command::DefaultSlashCommand, false);
     slash_command_registry.register_command(terminal_command::TerminalSlashCommand, true);
     slash_command_registry.register_command(now_command::NowSlashCommand, false);
     slash_command_registry.register_command(diagnostics_command::DiagnosticsSlashCommand, true);
+    slash_command_registry.register_command(fetch_command::FetchSlashCommand, false);
 
     if let Some(prompt_builder) = prompt_builder {
         slash_command_registry.register_command(
             workflow_command::WorkflowSlashCommand::new(prompt_builder.clone()),
             true,
         );
+        cx.observe_flag::<project_command::ProjectSlashCommandFeatureFlag, _>({
+            let slash_command_registry = slash_command_registry.clone();
+            move |is_enabled, _cx| {
+                if is_enabled {
+                    slash_command_registry.register_command(
+                        project_command::ProjectSlashCommand::new(prompt_builder.clone()),
+                        true,
+                    );
+                }
+            }
+        })
+        .detach();
     }
-    slash_command_registry.register_command(fetch_command::FetchSlashCommand, false);
 
     cx.observe_flag::<auto_command::AutoSlashCommandFeatureFlag, _>({
         let slash_command_registry = slash_command_registry.clone();
@@ -435,10 +449,12 @@ fn update_slash_commands_from_settings(cx: &mut AppContext) {
         slash_command_registry.unregister_command(docs_command::DocsSlashCommand);
     }
 
-    if settings.project.enabled {
-        slash_command_registry.register_command(project_command::ProjectSlashCommand, true);
+    if settings.cargo_workspace.enabled {
+        slash_command_registry
+            .register_command(cargo_workspace_command::CargoWorkspaceSlashCommand, true);
     } else {
-        slash_command_registry.unregister_command(project_command::ProjectSlashCommand);
+        slash_command_registry
+            .unregister_command(cargo_workspace_command::CargoWorkspaceSlashCommand);
     }
 }
 

crates/assistant/src/context.rs

@@ -1967,8 +1967,9 @@ impl Context {
     }
 
     pub fn assist(&mut self, cx: &mut ModelContext<Self>) -> Option<MessageAnchor> {
-        let provider = LanguageModelRegistry::read_global(cx).active_provider()?;
-        let model = LanguageModelRegistry::read_global(cx).active_model()?;
+        let model_registry = LanguageModelRegistry::read_global(cx);
+        let provider = model_registry.active_provider()?;
+        let model = model_registry.active_model()?;
         let last_message_id = self.get_last_valid_message_id(cx)?;
 
         if !provider.is_authenticated(cx) {

crates/assistant/src/prompts.rs

@@ -40,6 +40,11 @@ pub struct TerminalAssistantPromptContext {
     pub user_prompt: String,
 }
 
+#[derive(Serialize)]
+pub struct ProjectSlashCommandPromptContext {
+    pub context_buffer: String,
+}
+
 /// Context required to generate a workflow step resolution prompt.
 #[derive(Debug, Serialize)]
 pub struct StepResolutionContext {
@@ -317,4 +322,14 @@ impl PromptBuilder {
     pub fn generate_workflow_prompt(&self) -> Result<String, RenderError> {
         self.handlebars.lock().render("edit_workflow", &())
     }
+
+    pub fn generate_project_slash_command_prompt(
+        &self,
+        context_buffer: String,
+    ) -> Result<String, RenderError> {
+        self.handlebars.lock().render(
+            "project_slash_command",
+            &ProjectSlashCommandPromptContext { context_buffer },
+        )
+    }
 }

crates/assistant/src/slash_command.rs

@@ -18,8 +18,8 @@ use std::{
 };
 use ui::ActiveTheme;
 use workspace::Workspace;
-
 pub mod auto_command;
+pub mod cargo_workspace_command;
 pub mod context_server_command;
 pub mod default_command;
 pub mod delta_command;

crates/assistant/src/slash_command/cargo_workspace_command.rs

@@ -0,0 +1,153 @@
+use super::{SlashCommand, SlashCommandOutput};
+use anyhow::{anyhow, Context, Result};
+use assistant_slash_command::{ArgumentCompletion, SlashCommandOutputSection};
+use fs::Fs;
+use gpui::{AppContext, Model, Task, WeakView};
+use language::{BufferSnapshot, LspAdapterDelegate};
+use project::{Project, ProjectPath};
+use std::{
+    fmt::Write,
+    path::Path,
+    sync::{atomic::AtomicBool, Arc},
+};
+use ui::prelude::*;
+use workspace::Workspace;
+
+pub(crate) struct CargoWorkspaceSlashCommand;
+
+impl CargoWorkspaceSlashCommand {
+    async fn build_message(fs: Arc<dyn Fs>, path_to_cargo_toml: &Path) -> Result<String> {
+        let buffer = fs.load(path_to_cargo_toml).await?;
+        let cargo_toml: cargo_toml::Manifest = toml::from_str(&buffer)?;
+
+        let mut message = String::new();
+        writeln!(message, "You are in a Rust project.")?;
+
+        if let Some(workspace) = cargo_toml.workspace {
+            writeln!(
+                message,
+                "The project is a Cargo workspace with the following members:"
+            )?;
+            for member in workspace.members {
+                writeln!(message, "- {member}")?;
+            }
+
+            if !workspace.default_members.is_empty() {
+                writeln!(message, "The default members are:")?;
+                for member in workspace.default_members {
+                    writeln!(message, "- {member}")?;
+                }
+            }
+
+            if !workspace.dependencies.is_empty() {
+                writeln!(
+                    message,
+                    "The following workspace dependencies are installed:"
+                )?;
+                for dependency in workspace.dependencies.keys() {
+                    writeln!(message, "- {dependency}")?;
+                }
+            }
+        } else if let Some(package) = cargo_toml.package {
+            writeln!(
+                message,
+                "The project name is \"{name}\".",
+                name = package.name
+            )?;
+
+            let description = package
+                .description
+                .as_ref()
+                .and_then(|description| description.get().ok().cloned());
+            if let Some(description) = description.as_ref() {
+                writeln!(message, "It describes itself as \"{description}\".")?;
+            }
+
+            if !cargo_toml.dependencies.is_empty() {
+                writeln!(message, "The following dependencies are installed:")?;
+                for dependency in cargo_toml.dependencies.keys() {
+                    writeln!(message, "- {dependency}")?;
+                }
+            }
+        }
+
+        Ok(message)
+    }
+
+    fn path_to_cargo_toml(project: Model<Project>, cx: &mut AppContext) -> Option<Arc<Path>> {
+        let worktree = project.read(cx).worktrees(cx).next()?;
+        let worktree = worktree.read(cx);
+        let entry = worktree.entry_for_path("Cargo.toml")?;
+        let path = ProjectPath {
+            worktree_id: worktree.id(),
+            path: entry.path.clone(),
+        };
+        Some(Arc::from(
+            project.read(cx).absolute_path(&path, cx)?.as_path(),
+        ))
+    }
+}
+
+impl SlashCommand for CargoWorkspaceSlashCommand {
+    fn name(&self) -> String {
+        "cargo-workspace".into()
+    }
+
+    fn description(&self) -> String {
+        "insert project workspace metadata".into()
+    }
+
+    fn menu_text(&self) -> String {
+        "Insert Project Workspace Metadata".into()
+    }
+
+    fn complete_argument(
+        self: Arc<Self>,
+        _arguments: &[String],
+        _cancel: Arc<AtomicBool>,
+        _workspace: Option<WeakView<Workspace>>,
+        _cx: &mut WindowContext,
+    ) -> Task<Result<Vec<ArgumentCompletion>>> {
+        Task::ready(Err(anyhow!("this command does not require argument")))
+    }
+
+    fn requires_argument(&self) -> bool {
+        false
+    }
+
+    fn run(
+        self: Arc<Self>,
+        _arguments: &[String],
+        _context_slash_command_output_sections: &[SlashCommandOutputSection<language::Anchor>],
+        _context_buffer: BufferSnapshot,
+        workspace: WeakView<Workspace>,
+        _delegate: Option<Arc<dyn LspAdapterDelegate>>,
+        cx: &mut WindowContext,
+    ) -> Task<Result<SlashCommandOutput>> {
+        let output = workspace.update(cx, |workspace, cx| {
+            let project = workspace.project().clone();
+            let fs = workspace.project().read(cx).fs().clone();
+            let path = Self::path_to_cargo_toml(project, cx);
+            let output = cx.background_executor().spawn(async move {
+                let path = path.with_context(|| "Cargo.toml not found")?;
+                Self::build_message(fs, &path).await
+            });
+
+            cx.foreground_executor().spawn(async move {
+                let text = output.await?;
+                let range = 0..text.len();
+                Ok(SlashCommandOutput {
+                    text,
+                    sections: vec![SlashCommandOutputSection {
+                        range,
+                        icon: IconName::FileTree,
+                        label: "Project".into(),
+                        metadata: None,
+                    }],
+                    run_commands_in_text: false,
+                })
+            })
+        });
+        output.unwrap_or_else(|error| Task::ready(Err(error)))
+    }
+}