Improve Cause Rendering (Vitest) (#2747)

Co-authored-by: Tim <hello@timsmart.co>

.changeset/gorgeous-students-jog.md

@@ -0,0 +1,6 @@
+---
+"effect": minor
+"@effect/vitest": minor
+---
+
+Improve causal rendering in vitest by rethrowing pretty errors

.changeset/soft-moons-raise.md

@@ -0,0 +1,5 @@
+---
+"@effect/vitest": patch
+---
+
+Throw plain error object derived from fiber failure

.changeset/tough-buses-brush.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Consider Generator.next a cutpoint

packages/effect/src/internal/cause.ts

@@ -977,12 +977,25 @@ export const pretty = <E>(cause: Cause.Cause<E>): string => {
 }
 
 class PrettyError extends globalThis.Error implements Cause.PrettyError {
+  span: undefined | Span = undefined
   constructor(originalError: unknown) {
     const prevLimit = Error.stackTraceLimit
     Error.stackTraceLimit = 0
-    super(prettyErrorMessage(originalError), { cause: originalError })
+    super(prettyErrorMessage(originalError))
     Error.stackTraceLimit = prevLimit
+
     this.name = originalError instanceof Error ? originalError.name : "Error"
+    if (typeof originalError === "object" && originalError !== null) {
+      if (spanSymbol in originalError) {
+        this.span = originalError[spanSymbol] as Span
+      }
+      Object.keys(originalError).forEach((key) => {
+        if (!(key in this)) {
+          // @ts-expect-error
+          this[key] = originalError[key]
+        }
+      })
+    }
     this.stack = prettyErrorStack(
       this.message,
       originalError instanceof Error && originalError.stack
@@ -992,10 +1005,6 @@ class PrettyError extends globalThis.Error implements Cause.PrettyError {
     )
   }
 
-  get span(): Span | undefined {
-    return hasProperty(this.cause, spanSymbol) ? this.cause[spanSymbol] as Span : undefined
-  }
-
   toJSON() {
     const out: any = { message: this.message, stack: this.stack }
     if (this.span) {
@@ -1048,7 +1057,7 @@ const prettyErrorStack = (message: string, stack: string, span?: Span | undefine
   const lines = stack.split("\n")
 
   for (let i = 1; i < lines.length; i++) {
-    if (lines[i].includes("effect_cutpoint")) {
+    if (lines[i].includes("effect_cutpoint") || lines[i].includes("Generator.next")) {
       break
     }
     out.push(

packages/effect/src/internal/fiberRuntime.ts

@@ -1335,7 +1335,7 @@ export class FiberRuntime<in out A, in out E = never> implements Fiber.RuntimeFi
             internalCause.sequential(internalCause.die(e), internalCause.interrupt(FiberId.none))
           )
         } else {
-          cur = core.exitFailCause(internalCause.die(e))
+          cur = core.die(e)
         }
       }
     }

packages/effect/src/internal/runtime.ts

@@ -179,6 +179,10 @@ class FiberFailureImpl extends Error implements Runtime.FiberFailure {
     }
 
     this.name = `(FiberFailure) ${this.name}`
+
+    if (this.message === undefined || this.message.length === 0) {
+      this.message = "An error has occurred"
+    }
   }
 
   toJSON(): unknown {
@@ -187,6 +191,7 @@ class FiberFailureImpl extends Error implements Runtime.FiberFailure {
       cause: this[FiberFailureCauseId].toJSON()
     }
   }
+
   toString(): string {
     return "(FiberFailure) " + (this.stack ?? this.message)
   }

packages/effect/test/Effect/cause-rendering.test.ts

@@ -117,4 +117,21 @@ describe("Effect", () => {
       assert.include(error.stack, "span-123")
       assert.include(error.stack, "cause-rendering.test.ts:110")
     }))
+
+  it.effect("includes span name in stack", () =>
+    Effect.gen(function*() {
+      const fn = Effect.functionWithSpan({
+        options: (n) => ({ name: `fn-${n}` }),
+        body: (a: number) =>
+          Effect.sync(() => {
+            assert.strictEqual(a, 2)
+          })
+      })
+      const cause = yield* fn(0).pipe(
+        Effect.sandbox,
+        Effect.flip
+      )
+      const prettyErrors = Cause.prettyErrors(cause)
+      assert.include(prettyErrors[0].stack ?? "", "at fn-0 ")
+    }))
 })

packages/vitest/src/index.ts

@@ -2,9 +2,11 @@
  * @since 1.0.0
  */
 import type { Tester, TesterContext } from "@vitest/expect"
+import * as Cause from "effect/Cause"
 import * as Duration from "effect/Duration"
 import * as Effect from "effect/Effect"
 import * as Equal from "effect/Equal"
+import * as Exit from "effect/Exit"
 import { pipe } from "effect/Function"
 import * as Layer from "effect/Layer"
 import * as Logger from "effect/Logger"
@@ -16,6 +18,22 @@ import * as Utils from "effect/Utils"
 import type { TestAPI } from "vitest"
 import * as V from "vitest"
 
+const runTest = <E, A>(effect: Effect.Effect<A, E>) =>
+  Effect.gen(function*() {
+    const exit: Exit.Exit<A, E> = yield* Effect.exit(effect)
+    if (Exit.isSuccess(exit)) {
+      return () => {}
+    } else {
+      const errors = Cause.prettyErrors(exit.cause)
+      for (let i = 1; i < errors.length; i++) {
+        yield* Effect.logError(errors[i])
+      }
+      return () => {
+        throw errors[0]
+      }
+    }
+  }).pipe(Effect.runPromise).then((f) => f())
+
 /**
  * @since 1.0.0
  */
@@ -58,7 +76,7 @@ export const effect = (() => {
         pipe(
           Effect.suspend(() => self(c)),
           Effect.provide(TestEnv),
-          Effect.runPromise
+          runTest
         ),
       timeout
     )
@@ -74,7 +92,7 @@ export const effect = (() => {
           pipe(
             Effect.suspend(() => self(c)),
             Effect.provide(TestEnv),
-            Effect.runPromise
+            runTest
           ),
         timeout
       ),
@@ -89,7 +107,7 @@ export const effect = (() => {
           pipe(
             Effect.suspend(() => self(c)),
             Effect.provide(TestEnv),
-            Effect.runPromise
+            runTest
           ),
         timeout
       )
@@ -109,7 +127,7 @@ export const live = <E, A>(
     (c) =>
       pipe(
         Effect.suspend(() => self(c)),
-        Effect.runPromise
+        runTest
       ),
     timeout
   )
@@ -150,7 +168,7 @@ export const scoped = <E, A>(
         Effect.suspend(() => self(c)),
         Effect.scoped,
         Effect.provide(TestEnv),
-        Effect.runPromise
+        runTest
       ),
     timeout
   )
@@ -169,7 +187,7 @@ export const scopedLive = <E, A>(
       pipe(
         Effect.suspend(() => self(c)),
         Effect.scoped,
-        Effect.runPromise
+        runTest
       ),
     timeout
   )