Show login options when not signed in with ChatGPT (#2440)

Motivation: we have users who uses their API key although they want to
use ChatGPT account. We want to give them the chance to always login
with their account.

This PR displays login options when the user is not signed in with
ChatGPT. Even if you have set an OpenAI API key as an environment
variable, you will still be prompted to log in with ChatGPT.

We’ve also added a new flag, `always_use_api_key_signing` false by
default, which ensures you are never asked to log in with ChatGPT and
always defaults to using your API key.



https://github.com/user-attachments/assets/b61ebfa9-3c5e-4ab7-bf94-395c23a0e0af

After ChatGPT sign in:


https://github.com/user-attachments/assets/d58b366b-c46a-428f-a22f-2ac230f991c0

codex-rs/core/src/config.rs

@@ -13,6 +13,7 @@ use crate::model_provider_info::built_in_model_providers;
 use crate::openai_model_info::get_model_info;
 use crate::protocol::AskForApproval;
 use crate::protocol::SandboxPolicy;
+use codex_login::AuthMode;
 use codex_protocol::config_types::ReasoningEffort;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::SandboxMode;
@@ -163,6 +164,9 @@ pub struct Config {
 
     /// The value for the `originator` header included with Responses API requests.
     pub internal_originator: Option<String>,
+
+    /// If set to `true`, the API key will be signed with the `originator` header.
+    pub preferred_auth_method: AuthMode,
 }
 
 impl Config {
@@ -409,6 +413,9 @@ pub struct ConfigToml {
     pub internal_originator: Option<String>,
 
     pub projects: Option<HashMap<String, ProjectConfig>>,
+
+    /// If set to `true`, the API key will be signed with the `originator` header.
+    pub preferred_auth_method: Option<AuthMode>,
 }
 
 #[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
@@ -672,6 +679,7 @@ impl Config {
             include_plan_tool: include_plan_tool.unwrap_or(false),
             include_apply_patch_tool: include_apply_patch_tool_val,
             internal_originator: cfg.internal_originator,
+            preferred_auth_method: cfg.preferred_auth_method.unwrap_or(AuthMode::ChatGPT),
         };
         Ok(config)
     }
@@ -1036,6 +1044,7 @@ disable_response_storage = true
                 include_plan_tool: false,
                 include_apply_patch_tool: false,
                 internal_originator: None,
+                preferred_auth_method: AuthMode::ChatGPT,
             },
             o3_profile_config
         );
@@ -1088,6 +1097,7 @@ disable_response_storage = true
             include_plan_tool: false,
             include_apply_patch_tool: false,
             internal_originator: None,
+            preferred_auth_method: AuthMode::ChatGPT,
         };
 
         assert_eq!(expected_gpt3_profile_config, gpt3_profile_config);
@@ -1155,6 +1165,7 @@ disable_response_storage = true
             include_plan_tool: false,
             include_apply_patch_tool: false,
             internal_originator: None,
+            preferred_auth_method: AuthMode::ChatGPT,
         };
 
         assert_eq!(expected_zdr_profile_config, zdr_profile_config);

codex-rs/core/src/conversation_manager.rs

@@ -40,7 +40,7 @@ impl Default for ConversationManager {
 
 impl ConversationManager {
     pub async fn new_conversation(&self, config: Config) -> CodexResult<NewConversation> {
-        let auth = CodexAuth::from_codex_home(&config.codex_home)?;
+        let auth = CodexAuth::from_codex_home(&config.codex_home, config.preferred_auth_method)?;
         self.new_conversation_with_auth(config, auth).await
     }