From 92f739dbb9f2b46a1d825b39c0ea2c521dae0dbc Mon Sep 17 00:00:00 2001
From: Cole Miller <cole@zed.dev>
Date: Fri, 29 Aug 2025 13:40:39 -0400
Subject: [PATCH] acp: Improve error reporting and log more information when
 failing to launch gemini (#37178)

In the case where we fail to create an ACP connection to Gemini, only
report the "unsupported version" error if the version for the found
binary is at least our minimum version. That means we'll surface the
real error in this situation.

This also fixes incorrect sorting of downloaded Gemini versions--as @kpe
pointed out we were effectively using the version string as a key. Now
we'll correctly use the parsed semver::Version instead.

Release Notes:

- N/A
---
 crates/agent_servers/src/agent_servers.rs | 11 ++++---
 crates/agent_servers/src/gemini.rs        | 39 ++++++++++++++---------
 2 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/crates/agent_servers/src/agent_servers.rs b/crates/agent_servers/src/agent_servers.rs
index c1fc7b91ae862a25eac8da998f4b848327a3dd3e..c610c53ea8d61d24ece6d3c80ec15505d259ea3b 100644
--- a/crates/agent_servers/src/agent_servers.rs
+++ b/crates/agent_servers/src/agent_servers.rs
@@ -105,22 +105,23 @@ impl AgentServerDelegate {
                         .to_str()
                         .and_then(|name| semver::Version::from_str(&name).ok())
                     {
-                        versions.push((file_name.to_owned(), version));
+                        versions.push((version, file_name.to_owned()));
                     } else {
                         to_delete.push(file_name.to_owned())
                     }
                 }
 
                 versions.sort();
-                let newest_version = if let Some((file_name, version)) = versions.last().cloned()
-                    && minimum_version.is_none_or(|minimum_version| version > minimum_version)
+                let newest_version = if let Some((version, file_name)) = versions.last().cloned()
+                    && minimum_version.is_none_or(|minimum_version| version >= minimum_version)
                 {
                     versions.pop();
                     Some(file_name)
                 } else {
                     None
                 };
-                to_delete.extend(versions.into_iter().map(|(file_name, _)| file_name));
+                log::debug!("existing version of {package_name}: {newest_version:?}");
+                to_delete.extend(versions.into_iter().map(|(_, file_name)| file_name));
 
                 cx.background_spawn({
                     let fs = fs.clone();
@@ -200,6 +201,8 @@ impl AgentServerDelegate {
         node_runtime: NodeRuntime,
         package_name: SharedString,
     ) -> Result<String> {
+        log::debug!("downloading latest version of {package_name}");
+
         let tmp_dir = tempfile::tempdir_in(&dir)?;
 
         node_runtime
diff --git a/crates/agent_servers/src/gemini.rs b/crates/agent_servers/src/gemini.rs
index 5e958f686959d78e6ceaf8b8ea7d8404ffba166a..a1553d288ab44d96bdfe08723a092ce231ba005b 100644
--- a/crates/agent_servers/src/gemini.rs
+++ b/crates/agent_servers/src/gemini.rs
@@ -63,7 +63,9 @@ impl AgentServer for Gemini {
                 })?
                 .await?
             };
-            command.args.push("--experimental-acp".into());
+            if !command.args.contains(&ACP_ARG.into()) {
+                command.args.push(ACP_ARG.into());
+            }
 
             if let Some(api_key) = cx.update(GoogleLanguageModelProvider::api_key)?.await.ok() {
                 command
@@ -86,17 +88,17 @@ impl AgentServer for Gemini {
                             .await;
                         let current_version =
                             String::from_utf8(version_output?.stdout)?.trim().to_owned();
-                        if !connection.prompt_capabilities().image {
-                            return Err(LoadError::Unsupported {
-                                current_version: current_version.into(),
-                                command: command.path.to_string_lossy().to_string().into(),
-                                minimum_version: Self::MINIMUM_VERSION.into(),
-                            }
-                            .into());
+
+                        log::error!("connected to gemini, but missing prompt_capabilities.image (version is {current_version})");
+                        return Err(LoadError::Unsupported {
+                            current_version: current_version.into(),
+                            command: command.path.to_string_lossy().to_string().into(),
+                            minimum_version: Self::MINIMUM_VERSION.into(),
                         }
+                        .into());
                     }
                 }
-                Err(_) => {
+                Err(e) => {
                     let version_fut = util::command::new_smol_command(&command.path)
                         .args(command.args.iter())
                         .arg("--version")
@@ -111,12 +113,19 @@ impl AgentServer for Gemini {
 
                     let (version_output, help_output) =
                         futures::future::join(version_fut, help_fut).await;
-
-                    let current_version = std::str::from_utf8(&version_output?.stdout)?
-                        .trim()
-                        .to_string();
-                    let supported = String::from_utf8(help_output?.stdout)?.contains(ACP_ARG);
-
+                    let Some(version_output) = version_output.ok().and_then(|output| String::from_utf8(output.stdout).ok()) else {
+                        return result;
+                    };
+                    let Some((help_stdout, help_stderr)) = help_output.ok().and_then(|output| String::from_utf8(output.stdout).ok().zip(String::from_utf8(output.stderr).ok())) else  {
+                        return result;
+                    };
+
+                    let current_version = version_output.trim().to_string();
+                    let supported = help_stdout.contains(ACP_ARG) || current_version.parse::<semver::Version>().is_ok_and(|version| version >= Self::MINIMUM_VERSION.parse::<semver::Version>().unwrap());
+
+                    log::error!("failed to create ACP connection to gemini (version is {current_version}, supported: {supported}): {e}");
+                    log::debug!("gemini --help stdout: {help_stdout:?}");
+                    log::debug!("gemini --help stderr: {help_stderr:?}");
                     if !supported {
                         return Err(LoadError::Unsupported {
                             current_version: current_version.into(),