storkit: merge 387_story_configurable_base_branch_name_in_project_toml

server/src/config.rs

@@ -30,6 +30,12 @@ pub struct ProjectConfig {
     /// Default: 2. Set to 0 to disable retry limits.
     #[serde(default = "default_max_retries")]
     pub max_retries: u32,
+    /// Optional base branch name (e.g. "main", "master", "develop").
+    /// When set, overrides the auto-detection logic (`detect_base_branch`) for all
+    /// worktree creation, merge operations, and agent prompt `{{base_branch}}` substitution.
+    /// When not set, the system falls back to `detect_base_branch` (reads current HEAD).
+    #[serde(default)]
+    pub base_branch: Option<String>,
 }
 
 /// Configuration for the filesystem watcher's sweep behaviour.
@@ -164,6 +170,8 @@ struct LegacyProjectConfig {
     max_coders: Option<usize>,
     #[serde(default = "default_max_retries")]
     max_retries: u32,
+    #[serde(default)]
+    base_branch: Option<String>,
 }
 
 impl Default for ProjectConfig {
@@ -190,6 +198,7 @@ impl Default for ProjectConfig {
             default_coder_model: None,
             max_coders: None,
             max_retries: default_max_retries(),
+            base_branch: None,
         }
     }
 }
@@ -235,6 +244,7 @@ impl ProjectConfig {
                             default_coder_model: legacy.default_coder_model,
                             max_coders: legacy.max_coders,
                             max_retries: legacy.max_retries,
+                            base_branch: legacy.base_branch,
                         };
                         validate_agents(&config.agent)?;
                         return Ok(config);
@@ -259,6 +269,7 @@ impl ProjectConfig {
                         default_coder_model: legacy.default_coder_model,
                         max_coders: legacy.max_coders,
                         max_retries: legacy.max_retries,
+                        base_branch: legacy.base_branch,
                     };
                     validate_agents(&config.agent)?;
                     Ok(config)
@@ -271,6 +282,7 @@ impl ProjectConfig {
                         default_coder_model: legacy.default_coder_model,
                         max_coders: legacy.max_coders,
                         max_retries: legacy.max_retries,
+                        base_branch: legacy.base_branch,
                     })
                 }
             }
@@ -312,7 +324,9 @@ impl ProjectConfig {
                 .ok_or_else(|| "No agents configured".to_string())?,
         };
 
-        let bb = base_branch.unwrap_or("master");
+        let bb = base_branch
+            .or(self.base_branch.as_deref())
+            .unwrap_or("master");
         let aname = agent.name.as_str();
         let render = |s: &str| {
             s.replace("{{worktree_path}}", worktree_path)
@@ -858,6 +872,80 @@ runtime = "openai"
         assert!(err.contains("unknown runtime 'openai'"));
     }
 
+    // ── base_branch config ──────────────────────────────────────────────────
+
+    #[test]
+    fn base_branch_defaults_to_none() {
+        let toml_str = r#"
+[[agent]]
+name = "coder"
+"#;
+        let config = ProjectConfig::parse(toml_str).unwrap();
+        assert_eq!(config.base_branch, None);
+    }
+
+    #[test]
+    fn base_branch_parsed_when_set() {
+        let toml_str = r#"
+base_branch = "main"
+
+[[agent]]
+name = "coder"
+"#;
+        let config = ProjectConfig::parse(toml_str).unwrap();
+        assert_eq!(config.base_branch, Some("main".to_string()));
+    }
+
+    #[test]
+    fn render_agent_args_uses_config_base_branch_when_caller_passes_none() {
+        let toml_str = r#"
+base_branch = "develop"
+
+[[agent]]
+name = "coder"
+prompt = "git difftool {{base_branch}}...HEAD"
+"#;
+        let config = ProjectConfig::parse(toml_str).unwrap();
+        let (_, _, prompt) = config
+            .render_agent_args("/tmp/wt", "42_foo", None, None)
+            .unwrap();
+        assert!(
+            prompt.contains("develop"),
+            "Expected 'develop' in prompt, got: {prompt}"
+        );
+    }
+
+    #[test]
+    fn render_agent_args_caller_base_branch_takes_precedence_over_config() {
+        let toml_str = r#"
+base_branch = "develop"
+
+[[agent]]
+name = "coder"
+prompt = "git difftool {{base_branch}}...HEAD"
+"#;
+        let config = ProjectConfig::parse(toml_str).unwrap();
+        let (_, _, prompt) = config
+            .render_agent_args("/tmp/wt", "42_foo", None, Some("feature-x"))
+            .unwrap();
+        assert!(
+            prompt.contains("feature-x"),
+            "Caller-supplied base_branch should win, got: {prompt}"
+        );
+    }
+
+    #[test]
+    fn project_toml_has_base_branch_master() {
+        let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
+        let project_root = manifest_dir.parent().unwrap();
+        let config = ProjectConfig::load(project_root).unwrap();
+        assert_eq!(
+            config.base_branch,
+            Some("master".to_string()),
+            "project.toml must have base_branch = \"master\""
+        );
+    }
+
     #[test]
     fn project_toml_has_three_sonnet_coders() {
         let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));