debugger: Add support for inline value hints (#28656)

This PR uses Tree Sitter to show inline values while a user is in a
debug session.

We went with Tree Sitter over the LSP Inline Values request because the
LSP request isn't widely supported. Tree Sitter is easy for
languages/extensions to add support to. Tree Sitter can compute the
inline values locally, so there's no need to add extra RPC messages for
Collab. Tree Sitter also gives Zed more control over how we want to show
variables.

There's still more work to be done after this PR, namely differentiating
between global/local scoped variables, but it's a great starting point
to start iteratively improving it.

Release Notes:

- N/A

---------

Co-authored-by: Piotr Osiewicz <peterosiewicz@gmail.com>
Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Cole Miller <m@cole-miller.net>
Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Kirill <kirill@zed.dev>

crates/project/src/debugger/dap_store.rs

@@ -4,7 +4,7 @@ use super::{
     session::{self, Session, SessionStateEvent},
 };
 use crate::{
-    ProjectEnvironment,
+    InlayHint, InlayHintLabel, ProjectEnvironment, ResolveState,
     project_settings::ProjectSettings,
     terminals::{SshCommand, wrap_for_ssh},
     worktree_store::WorktreeStore,
@@ -15,7 +15,7 @@ use collections::HashMap;
 use dap::{
     Capabilities, CompletionItem, CompletionsArguments, DapRegistry, EvaluateArguments,
     EvaluateArgumentsContext, EvaluateResponse, RunInTerminalRequestArguments, Source,
-    StartDebuggingRequestArguments,
+    StackFrameId, StartDebuggingRequestArguments,
     adapters::{DapStatus, DebugAdapterBinary, DebugAdapterName, TcpArguments},
     client::SessionId,
     messages::Message,
@@ -28,7 +28,10 @@ use futures::{
 };
 use gpui::{App, AppContext, AsyncApp, Context, Entity, EventEmitter, SharedString, Task};
 use http_client::HttpClient;
-use language::{BinaryStatus, LanguageRegistry, LanguageToolchainStore};
+use language::{
+    BinaryStatus, Buffer, LanguageRegistry, LanguageToolchainStore,
+    language_settings::InlayHintKind, range_from_lsp,
+};
 use lsp::LanguageServerName;
 use node_runtime::NodeRuntime;
 
@@ -763,6 +766,103 @@ impl DapStore {
         })
     }
 
+    pub fn resolve_inline_values(
+        &self,
+        session: Entity<Session>,
+        stack_frame_id: StackFrameId,
+        buffer_handle: Entity<Buffer>,
+        inline_values: Vec<lsp::InlineValue>,
+        cx: &mut Context<Self>,
+    ) -> Task<Result<Vec<InlayHint>>> {
+        let snapshot = buffer_handle.read(cx).snapshot();
+        let all_variables = session.read(cx).variables_by_stack_frame_id(stack_frame_id);
+
+        cx.spawn(async move |_, cx| {
+            let mut inlay_hints = Vec::with_capacity(inline_values.len());
+            for inline_value in inline_values.iter() {
+                match inline_value {
+                    lsp::InlineValue::Text(text) => {
+                        inlay_hints.push(InlayHint {
+                            position: snapshot.anchor_after(range_from_lsp(text.range).end),
+                            label: InlayHintLabel::String(format!(": {}", text.text)),
+                            kind: Some(InlayHintKind::Type),
+                            padding_left: false,
+                            padding_right: false,
+                            tooltip: None,
+                            resolve_state: ResolveState::Resolved,
+                        });
+                    }
+                    lsp::InlineValue::VariableLookup(variable_lookup) => {
+                        let range = range_from_lsp(variable_lookup.range);
+
+                        let mut variable_name = variable_lookup
+                            .variable_name
+                            .clone()
+                            .unwrap_or_else(|| snapshot.text_for_range(range.clone()).collect());
+
+                        if !variable_lookup.case_sensitive_lookup {
+                            variable_name = variable_name.to_ascii_lowercase();
+                        }
+
+                        let Some(variable) = all_variables.iter().find(|variable| {
+                            if variable_lookup.case_sensitive_lookup {
+                                variable.name == variable_name
+                            } else {
+                                variable.name.to_ascii_lowercase() == variable_name
+                            }
+                        }) else {
+                            continue;
+                        };
+
+                        inlay_hints.push(InlayHint {
+                            position: snapshot.anchor_after(range.end),
+                            label: InlayHintLabel::String(format!(": {}", variable.value)),
+                            kind: Some(InlayHintKind::Type),
+                            padding_left: false,
+                            padding_right: false,
+                            tooltip: None,
+                            resolve_state: ResolveState::Resolved,
+                        });
+                    }
+                    lsp::InlineValue::EvaluatableExpression(expression) => {
+                        let range = range_from_lsp(expression.range);
+
+                        let expression = expression
+                            .expression
+                            .clone()
+                            .unwrap_or_else(|| snapshot.text_for_range(range.clone()).collect());
+
+                        let Ok(eval_task) = session.update(cx, |session, cx| {
+                            session.evaluate(
+                                expression,
+                                Some(EvaluateArgumentsContext::Variables),
+                                Some(stack_frame_id),
+                                None,
+                                cx,
+                            )
+                        }) else {
+                            continue;
+                        };
+
+                        if let Some(response) = eval_task.await {
+                            inlay_hints.push(InlayHint {
+                                position: snapshot.anchor_after(range.end),
+                                label: InlayHintLabel::String(format!(": {}", response.result)),
+                                kind: Some(InlayHintKind::Type),
+                                padding_left: false,
+                                padding_right: false,
+                                tooltip: None,
+                                resolve_state: ResolveState::Resolved,
+                            });
+                        };
+                    }
+                };
+            }
+
+            Ok(inlay_hints)
+        })
+    }
+
     pub fn shutdown_sessions(&mut self, cx: &mut Context<Self>) -> Task<()> {
         let mut tasks = vec![];
         for session_id in self.sessions.keys().cloned().collect::<Vec<_>>() {