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>

crates/assistant/src/slash_command/search_command.rs

@@ -7,7 +7,7 @@ use anyhow::Result;
 use assistant_slash_command::{ArgumentCompletion, SlashCommandOutputSection};
 use feature_flags::FeatureFlag;
 use gpui::{AppContext, Task, WeakView};
-use language::{CodeLabel, LineEnding, LspAdapterDelegate};
+use language::{CodeLabel, LspAdapterDelegate};
 use semantic_index::{LoadedSearchResult, SemanticDb};
 use std::{
     fmt::Write,
@@ -101,7 +101,7 @@ impl SlashCommand for SearchSlashCommand {
         cx.spawn(|cx| async move {
             let results = project_index
                 .read_with(&cx, |project_index, cx| {
-                    project_index.search(query.clone(), limit.unwrap_or(5), cx)
+                    project_index.search(vec![query.clone()], limit.unwrap_or(5), cx)
                 })?
                 .await?;
 
@@ -112,31 +112,8 @@ impl SlashCommand for SearchSlashCommand {
                 .spawn(async move {
                     let mut text = format!("Search results for {query}:\n");
                     let mut sections = Vec::new();
-                    for LoadedSearchResult {
-                        path,
-                        range,
-                        full_path,
-                        file_content,
-                        row_range,
-                    } in loaded_results
-                    {
-                        let section_start_ix = text.len();
-                        text.push_str(&codeblock_fence_for_path(
-                            Some(&path),
-                            Some(row_range.clone()),
-                        ));
-
-                        let mut excerpt = file_content[range].to_string();
-                        LineEnding::normalize(&mut excerpt);
-                        text.push_str(&excerpt);
-                        writeln!(text, "\n```\n").unwrap();
-                        let section_end_ix = text.len() - 1;
-                        sections.push(build_entry_output_section(
-                            section_start_ix..section_end_ix,
-                            Some(&full_path),
-                            false,
-                            Some(row_range.start() + 1..row_range.end() + 1),
-                        ));
+                    for loaded_result in &loaded_results {
+                        add_search_result_section(loaded_result, &mut text, &mut sections);
                     }
 
                     let query = SharedString::from(query);
@@ -159,3 +136,35 @@ impl SlashCommand for SearchSlashCommand {
         })
     }
 }
+
+pub fn add_search_result_section(
+    loaded_result: &LoadedSearchResult,
+    text: &mut String,
+    sections: &mut Vec<SlashCommandOutputSection<usize>>,
+) {
+    let LoadedSearchResult {
+        path,
+        full_path,
+        excerpt_content,
+        row_range,
+        ..
+    } = loaded_result;
+    let section_start_ix = text.len();
+    text.push_str(&codeblock_fence_for_path(
+        Some(&path),
+        Some(row_range.clone()),
+    ));
+
+    text.push_str(&excerpt_content);
+    if !text.ends_with('\n') {
+        text.push('\n');
+    }
+    writeln!(text, "```\n").unwrap();
+    let section_end_ix = text.len() - 1;
+    sections.push(build_entry_output_section(
+        section_start_ix..section_end_ix,
+        Some(&full_path),
+        false,
+        Some(row_range.start() + 1..row_range.end() + 1),
+    ));
+}