Fix slash command argument completion bugs (#16233)

Release Notes:

- N/A

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/assistant/src/slash_command/diagnostics_command.rs

@@ -150,6 +150,7 @@ impl SlashCommand for DiagnosticsSlashCommand {
                     label: completion.clone().into(),
                     new_text: completion,
                     run_command: true,
+                    replace_previous_arguments: false,
                 })
                 .collect())
         })

crates/assistant/src/slash_command/docs_command.rs

@@ -182,6 +182,7 @@ impl SlashCommand for DocsSlashCommand {
                         label: item.clone().into(),
                         new_text: item.to_string(),
                         run_command: true,
+                        replace_previous_arguments: false,
                     })
                     .collect()
             }
@@ -194,6 +195,7 @@ impl SlashCommand for DocsSlashCommand {
                             label: "No available docs providers.".into(),
                             new_text: String::new(),
                             run_command: false,
+                            replace_previous_arguments: false,
                         }]);
                     }
 
@@ -203,6 +205,7 @@ impl SlashCommand for DocsSlashCommand {
                             label: provider.to_string().into(),
                             new_text: provider.to_string(),
                             run_command: false,
+                            replace_previous_arguments: false,
                         })
                         .collect())
                 }
@@ -234,6 +237,7 @@ impl SlashCommand for DocsSlashCommand {
                             label: format!("{package_name} (unindexed)").into(),
                             new_text: format!("{package_name}"),
                             run_command: true,
+                            replace_previous_arguments: false,
                         })
                         .collect::<Vec<_>>();
                     items.extend(workspace_crate_completions);
@@ -247,6 +251,7 @@ impl SlashCommand for DocsSlashCommand {
                             .into(),
                             new_text: provider.to_string(),
                             run_command: false,
+                            replace_previous_arguments: false,
                         }]);
                     }
 

crates/assistant/src/slash_command/file_command.rs

@@ -164,7 +164,8 @@ impl SlashCommand for FileSlashCommand {
                     Some(ArgumentCompletion {
                         label,
                         new_text: text,
-                        run_command: false,
+                        run_command: true,
+                        replace_previous_arguments: false,
                     })
                 })
                 .collect())

crates/assistant/src/slash_command/prompt_command.rs

@@ -35,7 +35,7 @@ impl SlashCommand for PromptSlashCommand {
         cx: &mut WindowContext,
     ) -> Task<Result<Vec<ArgumentCompletion>>> {
         let store = PromptStore::global(cx);
-        let query = arguments.last().cloned().unwrap_or_default();
+        let query = arguments.to_owned().join(" ");
         cx.background_executor().spawn(async move {
             let prompts = store.await?.search(query).await;
             Ok(prompts
@@ -46,6 +46,7 @@ impl SlashCommand for PromptSlashCommand {
                         label: prompt_title.clone().into(),
                         new_text: prompt_title,
                         run_command: true,
+                        replace_previous_arguments: true,
                     })
                 })
                 .collect())
@@ -59,12 +60,13 @@ impl SlashCommand for PromptSlashCommand {
         _delegate: Option<Arc<dyn LspAdapterDelegate>>,
         cx: &mut WindowContext,
     ) -> Task<Result<SlashCommandOutput>> {
-        let Some(title) = arguments.first() else {
+        let title = arguments.to_owned().join(" ");
+        if title.trim().is_empty() {
             return Task::ready(Err(anyhow!("missing prompt name")));
         };
 
         let store = PromptStore::global(cx);
-        let title = SharedString::from(title.to_string());
+        let title = SharedString::from(title.clone());
         let prompt = cx.background_executor().spawn({
             let title = title.clone();
             async move {

crates/assistant/src/slash_command/tab_command.rs

@@ -76,6 +76,7 @@ impl SlashCommand for TabSlashCommand {
                 Some(ArgumentCompletion {
                     label: path_string.clone().into(),
                     new_text: path_string,
+                    replace_previous_arguments: false,
                     run_command,
                 })
             });
@@ -83,6 +84,7 @@ impl SlashCommand for TabSlashCommand {
             Ok(Some(ArgumentCompletion {
                 label: ALL_TABS_COMPLETION_ITEM.into(),
                 new_text: ALL_TABS_COMPLETION_ITEM.to_owned(),
+                replace_previous_arguments: false,
                 run_command: true,
             })
             .into_iter()