test(session-recovery): add tests for detect-error-type resilience

Add test coverage for detectErrorType and extractMessageIndex with
edge cases: circular references, non-standard proxy errors, null input.
Wrap both functions in try/catch to prevent crashes from malformed
error objects returned by non-standard providers like Antigravity.

src/hooks/session-recovery/detect-error-type.test.ts

@@ -0,0 +1,129 @@
+/// <reference types="bun-types" />
+import { describe, expect, it } from "bun:test"
+import { detectErrorType, extractMessageIndex } from "./detect-error-type"
+
+describe("detectErrorType", () => {
+  it("#given a tool_use/tool_result error #when detecting #then returns tool_result_missing", () => {
+    //#given
+    const error = { message: "tool_use block must be followed by tool_result" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("tool_result_missing")
+  })
+
+  it("#given a thinking block order error #when detecting #then returns thinking_block_order", () => {
+    //#given
+    const error = { message: "thinking must be the first block in the response" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("thinking_block_order")
+  })
+
+  it("#given a thinking disabled violation #when detecting #then returns thinking_disabled_violation", () => {
+    //#given
+    const error = { message: "thinking is disabled and cannot contain thinking blocks" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("thinking_disabled_violation")
+  })
+
+  it("#given an unrecognized error #when detecting #then returns null", () => {
+    //#given
+    const error = { message: "some random error" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBeNull()
+  })
+
+  it("#given a malformed error with circular references #when detecting #then returns null without crashing", () => {
+    //#given
+    const circular: Record<string, unknown> = {}
+    circular.self = circular
+
+    //#when
+    const result = detectErrorType(circular)
+
+    //#then
+    expect(result).toBeNull()
+  })
+
+  it("#given a proxy error with non-standard structure #when detecting #then returns null without crashing", () => {
+    //#given
+    const proxyError = {
+      data: "not-an-object",
+      error: 42,
+      nested: { deeply: { error: true } },
+    }
+
+    //#when
+    const result = detectErrorType(proxyError)
+
+    //#then
+    expect(result).toBeNull()
+  })
+
+  it("#given a null error #when detecting #then returns null", () => {
+    //#given
+    const error = null
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBeNull()
+  })
+
+  it("#given an error with data.error containing message #when detecting #then extracts correctly", () => {
+    //#given
+    const error = {
+      data: {
+        error: {
+          message: "tool_use block requires tool_result",
+        },
+      },
+    }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("tool_result_missing")
+  })
+})
+
+describe("extractMessageIndex", () => {
+  it("#given an error referencing messages.5 #when extracting #then returns 5", () => {
+    //#given
+    const error = { message: "Invalid value at messages.5: tool_result is required" }
+
+    //#when
+    const result = extractMessageIndex(error)
+
+    //#then
+    expect(result).toBe(5)
+  })
+
+  it("#given a malformed error #when extracting #then returns null without crashing", () => {
+    //#given
+    const circular: Record<string, unknown> = {}
+    circular.self = circular
+
+    //#when
+    const result = extractMessageIndex(circular)
+
+    //#then
+    expect(result).toBeNull()
+  })
+})

src/hooks/session-recovery/detect-error-type.ts

@@ -34,12 +34,17 @@ function getErrorMessage(error: unknown): string {
 }
 
 export function extractMessageIndex(error: unknown): number | null {
+  try {
     const message = getErrorMessage(error)
     const match = message.match(/messages\.(\d+)/)
     return match ? parseInt(match[1], 10) : null
+  } catch {
+    return null
+  }
 }
 
 export function detectErrorType(error: unknown): RecoveryErrorType {
+  try {
     const message = getErrorMessage(error)
 
     if (
@@ -70,4 +75,7 @@ export function detectErrorType(error: unknown): RecoveryErrorType {
     }
 
     return null
+  } catch {
+    return null
+  }
 }