feat(events): preserve CLI context on session.resume

src/events.rs

@@ -119,6 +119,39 @@ pub struct SessionStartData {
 pub struct SessionResumeData {
     pub resume_time: String,
     pub event_count: f64,
+    /// Optional CLI-supplied workspace context. Copilot CLI 1.0.35+ sends
+    /// this object alongside the basic resume metadata so downstream
+    /// consumers (IDE integrations, session dashboards) can rebind to the
+    /// right working directory, git branch, and remote without re-reading
+    /// the session store. Older CLI versions omit the field entirely,
+    /// hence `Option` + `#[serde(default)]` keeps the type backward
+    /// compatible.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub context: Option<SessionResumeContext>,
+}
+
+/// Workspace context payload attached to a `session.resume` event by the
+/// Copilot CLI. Every field is optional because the CLI may omit any
+/// subset depending on whether the resumed session lives inside a git
+/// repository and which host (IDE / terminal / etc.) initiated the
+/// resume.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SessionResumeContext {
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub cwd: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub git_root: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub branch: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub base_commit: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub head_commit: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub repository: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub host_type: Option<String>,
 }
 
 /// Data for session.error event.
@@ -1447,4 +1480,76 @@ mod tests {
         let event = SessionEvent::from_json(&json).unwrap();
         assert_eq!(event.event_type, "session.usage_info");
     }
+
+    /// Regression fixture derived from the Copilot CLI 1.0.35 wire trace
+    /// captured during DevInSip POC-3 (see docs/POC_COPILOT_SDK.md in the
+    /// DevInSip repo). The CLI emits `session.resume` with an additional
+    /// `context` object that the pre-patch SDK silently dropped, leaving
+    /// downstream consumers (session binding, sidebar cwd) unable to
+    /// recover the working directory without bypassing the SDK.
+    #[test]
+    fn test_session_resume_preserves_cli_context() {
+        let json = json!({
+            "id": "evt_resume_1",
+            "timestamp": "2026-04-24T00:00:00Z",
+            "type": "session.resume",
+            "data": {
+                "resumeTime": "2026-04-24T00:00:00Z",
+                "eventCount": 42.0,
+                "context": {
+                    "cwd": "/Users/dev/project",
+                    "gitRoot": "/Users/dev/project",
+                    "branch": "main",
+                    "baseCommit": "abc123",
+                    "headCommit": "def456",
+                    "repository": "github.com/org/repo",
+                    "hostType": "vscode"
+                }
+            }
+        });
+
+        let event = SessionEvent::from_json(&json).unwrap();
+        assert_eq!(event.event_type, "session.resume");
+
+        let resume = match &event.data {
+            SessionEventData::SessionResume(r) => r,
+            other => panic!("expected SessionResume variant, got {other:?}"),
+        };
+        assert_eq!(resume.resume_time, "2026-04-24T00:00:00Z");
+        assert_eq!(resume.event_count, 42.0);
+
+        let ctx = resume
+            .context
+            .as_ref()
+            .expect("context must round-trip through SessionResumeData");
+        assert_eq!(ctx.cwd.as_deref(), Some("/Users/dev/project"));
+        assert_eq!(ctx.git_root.as_deref(), Some("/Users/dev/project"));
+        assert_eq!(ctx.branch.as_deref(), Some("main"));
+        assert_eq!(ctx.base_commit.as_deref(), Some("abc123"));
+        assert_eq!(ctx.head_commit.as_deref(), Some("def456"));
+        assert_eq!(ctx.repository.as_deref(), Some("github.com/org/repo"));
+        assert_eq!(ctx.host_type.as_deref(), Some("vscode"));
+    }
+
+    /// CLI payloads that omit `context` must still deserialize successfully
+    /// — the field is additive and backward-compatible.
+    #[test]
+    fn test_session_resume_without_context_is_backward_compatible() {
+        let json = json!({
+            "id": "evt_resume_2",
+            "timestamp": "2026-04-24T00:00:00Z",
+            "type": "session.resume",
+            "data": {
+                "resumeTime": "2026-04-24T00:00:00Z",
+                "eventCount": 0.0
+            }
+        });
+
+        let event = SessionEvent::from_json(&json).unwrap();
+        let resume = match &event.data {
+            SessionEventData::SessionResume(r) => r,
+            other => panic!("expected SessionResume variant, got {other:?}"),
+        };
+        assert!(resume.context.is_none());
+    }
 }