fix: causative errors are now also pretty-printed. @W-22797799@

src/errors/errors/pretty-print.ts

@@ -30,28 +30,47 @@ const formatSuggestions = (suggestions?: string[]): string | undefined => {
   return `${label}\n${indent(multiple, 2)}`
 }
 
-export default function prettyPrint(error: Error & PrettyPrintableError & CLIErrorDisplayOptions): string | undefined {
-  if (settings.debug) {
-    return error.stack
-  }
+type CombinedErrorType = Error & PrettyPrintableError & CLIErrorDisplayOptions
+
+function isCombinedErrorType(obj: any): obj is CombinedErrorType {
+  return Boolean(obj) && 'name' in obj && 'message' in obj
+}
+
+export default function prettyPrint(error: CombinedErrorType): string | undefined {
+  const prettyPrintedErrors: string[] = []
+  let currentError: unknown = error
+  let isDeep: boolean = false
+  while (isCombinedErrorType(currentError)) {
+    if (settings.debug && currentError.stack) {
+      prettyPrintedErrors.push(`${isDeep ? 'Caused by: ' : ''}${currentError.stack}`)
+    } else {
+      const {bang, code, message, name: errorSuffix, ref, suggestions} = currentError
 
-  const {bang, code, message, name: errorSuffix, ref, suggestions} = error
+      // errorSuffix is pulled from the 'name' property on CLIError
+      // and is like either Error or Warning
+      const formattedHeader = message ? `${errorSuffix || 'Error'}: ${message}` : undefined
+      const formattedCode = code ? `Code: ${code}` : undefined
+      const formattedSuggestions = formatSuggestions(suggestions)
+      const formattedReference = ref ? `Reference: ${ref}` : undefined
 
-  // errorSuffix is pulled from the 'name' property on CLIError
-  // and is like either Error or Warning
-  const formattedHeader = message ? `${errorSuffix || 'Error'}: ${message}` : undefined
-  const formattedCode = code ? `Code: ${code}` : undefined
-  const formattedSuggestions = formatSuggestions(suggestions)
-  const formattedReference = ref ? `Reference: ${ref}` : undefined
+      const formatted = [formattedHeader, formattedCode, formattedSuggestions, formattedReference]
+        .filter(Boolean)
+        .join('\n')
 
-  const formatted = [formattedHeader, formattedCode, formattedSuggestions, formattedReference]
-    .filter(Boolean)
-    .join('\n')
+      let output = `${isDeep ? 'Caused by: ' : ''}${formatted}`
+      output = wrap(output, errtermwidth - 6, {hard: true, trim: false} as any)
+      if (!settings.debug) {
+        output = indent(output, 3)
+        output = indent(output, 1, {includeEmptyLines: true, indent: bang || ''} as any)
+        output = indent(output, 1)
+      }
 
-  let output = wrap(formatted, errtermwidth - 6, {hard: true, trim: false} as any)
-  output = indent(output, 3)
-  output = indent(output, 1, {includeEmptyLines: true, indent: bang || ''} as any)
-  output = indent(output, 1)
+      prettyPrintedErrors.push(output)
+    }
+
+    isDeep = true
+    currentError = currentError.cause ?? null
+  }
 
-  return output
+  return prettyPrintedErrors.join('\n')
 }

test/errors/pretty-print.test.ts

@@ -7,7 +7,7 @@ import prettyPrint from '../../src/errors/errors/pretty-print'
 import {PrettyPrintableError} from '../../src/interfaces/errors'
 
 describe('pretty-print', () => {
-  it('pretty prints an error', async () => {
+  it('pretty prints a simple error', async () => {
     const sampleError: Error & PrettyPrintableError = new Error('Something very serious has gone wrong with the flags!')
     sampleError.ref = 'https://oclif.io/docs/flags'
     sampleError.code = 'OCLIF_BAD_FLAG'
@@ -20,6 +20,23 @@ describe('pretty-print', () => {
     Reference: https://oclif.io/docs/flags`)
   })
 
+  it('pretty prints an error and its causative error chain', async () => {
+    const rootError: Error & PrettyPrintableError = new Error('This error is the root error')
+    const errorOnceRemoved: Error & PrettyPrintableError = new Error(
+      'This error is one level removed from the root error',
+      {cause: rootError},
+    )
+    const errorTwiceRemoved: Error & PrettyPrintableError = new Error(
+      'This error is two levels removed from the root error',
+      {cause: errorOnceRemoved},
+    )
+
+    expect(ansis.strip(prettyPrint(errorTwiceRemoved) ?? '')).to
+      .equal(`    Error: This error is two levels removed from the root error
+    Caused by: Error: This error is one level removed from the root error
+    Caused by: Error: This error is the root error`)
+  })
+
   it('pretty prints multiple suggestions', async () => {
     const sampleError: Error & PrettyPrintableError = new Error('Something very serious has gone wrong with the flags!')
     sampleError.suggestions = ['Use a good flag', 'Use no flags']
@@ -75,5 +92,47 @@ describe('pretty-print', () => {
       error.stack = 'this is the error stack property'
       expect(prettyPrint(error)).to.equal('this is the error stack property')
     })
+
+    it('shows the stack for causative errors', async () => {
+      const rootError: Error & PrettyPrintableError = new Error('This error is the root error')
+      rootError.stack = String.raw`Root error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`
+      const errorOnceRemoved: Error & PrettyPrintableError = new Error(
+        'This error is one level removed from the root error',
+        {cause: rootError},
+      )
+      errorOnceRemoved.stack = String.raw`Once-removed error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`
+      const errorTwiceRemoved: Error & PrettyPrintableError = new Error(
+        'This error is two levels removed from the root error',
+        {cause: errorOnceRemoved},
+      )
+      errorTwiceRemoved.stack = String.raw`Twice-removed error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`
+
+      expect(prettyPrint(errorTwiceRemoved)).to.equal(
+        "Twice-removed error stack. In the wild, this would be something like 'Error: someMessage\\n\\tcodeStack'\n" +
+          "Caused by: Once-removed error stack. In the wild, this would be something like 'Error: someMessage\\n\\tcodeStack'\n" +
+          String.raw`Caused by: Root error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`,
+      )
+    })
+
+    it('when no stack is available, standard pretty print is used instead', () => {
+      const rootError: Error & PrettyPrintableError = new Error('This error is the root error')
+      rootError.stack = String.raw`Root error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`
+      const errorOnceRemoved: Error & PrettyPrintableError = new Error(
+        'This error is one level removed from the root error',
+        {cause: rootError},
+      )
+      delete errorOnceRemoved.stack
+      const errorTwiceRemoved: Error & PrettyPrintableError = new Error(
+        'This error is two levels removed from the root error',
+        {cause: errorOnceRemoved},
+      )
+      errorTwiceRemoved.stack = String.raw`Twice-removed error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`
+
+      expect(prettyPrint(errorTwiceRemoved)).to.equal(
+        "Twice-removed error stack. In the wild, this would be something like 'Error: someMessage\\n\\tcodeStack'\n" +
+          'Caused by: Error: This error is one level removed from the root error\n' +
+          String.raw`Caused by: Root error stack. In the wild, this would be something like 'Error: someMessage\n\tcodeStack'`,
+      )
+    })
   })
 })