Refactor to improve error conversion in esbuild

Closes GH-2595.

Reviewed-by: Titus Wormer <tituswormer@gmail.com>

Author: egnor

packages/esbuild/lib/index.js

@@ -1,6 +1,7 @@
 /**
  * @import {CompileOptions} from '@mdx-js/mdx'
  * @import {
+      Location,
       Message,
       OnLoadArgs,
       OnLoadResult,
@@ -117,14 +118,15 @@ export function esbuild(options) {
         messages = file.messages
       } catch (error_) {
         const cause = /** @type {VFileMessage | Error} */ (error_)
-        const message =
-          'reason' in cause
-            ? cause
-            : new VFileMessage('Cannot process MDX file with esbuild', {
-                cause,
-                ruleId: 'process-error',
-                source: '@mdx-js/esbuild'
-              })
+        const message = new VFileMessage(
+          'Cannot process MDX file with esbuild',
+          {
+            cause,
+            place: 'reason' in cause ? cause.place : undefined,
+            ruleId: 'process-error',
+            source: '@mdx-js/esbuild'
+          }
+        )
         message.fatal = true
         messages.push(message)
       }
@@ -157,44 +159,57 @@ export function esbuild(options) {
  *   ESBuild message.
  */
 function vfileMessageToEsbuild(state, message) {
+  /** @type {Location} */
+  const location = {
+    column: 0,
+    file: state.path,
+    length: 0,
+    line: 0,
+    lineText: '',
+    namespace: 'file',
+    suggestion: ''
+  }
+
   const place = message.place
   const start = place ? ('start' in place ? place.start : place) : undefined
-  const end = place && 'end' in place ? place.end : undefined
-  let length = 0
-  let lineStart = 0
-  let line = 0
-  let column = 0
-
-  if (start && start.offset !== undefined) {
-    line = start.line
-    column = start.column - 1
-    lineStart = start.offset - column
-    length = 1
-
-    if (end && end.offset !== undefined) {
-      length = end.offset - start.offset
+  if (start) {
+    location.column = start.column - 1
+    location.line = start.line
+    location.length = 1
+
+    const end = place && 'end' in place ? place.end : undefined
+    if (end) {
+      if (start.offset !== undefined && end.offset !== undefined) {
+        location.length = end.offset - start.offset
+      } else if (end.line === start.line) {
+        location.length = end.column - start.column
+      }
     }
-  }
 
-  eol.lastIndex = lineStart
+    if (start.offset !== undefined) {
+      eol.lastIndex = start.offset
+      const match = eol.exec(state.doc)
+      const lineStart = start.offset - (start.column - 1)
+      const lineEnd = match ? match.index : state.doc.length
+      location.lineText = state.doc.slice(lineStart, lineEnd)
+      location.length = Math.min(location.length, lineEnd - (start.offset || 0))
+    }
+
+    const maxLength = state.doc.length - (start.offset || 0)
+    location.length = Math.min(location.length, maxLength)
+  }
 
-  const match = eol.exec(state.doc)
-  const lineEnd = match ? match.index : state.doc.length
+  let text = message.reason
+  if (message.cause) {
+    text = `${text}:\n  ${message.cause}`
+  }
 
   return {
     detail: message,
     id: '',
-    location: {
-      column,
-      file: state.path,
-      length: Math.min(length, lineEnd),
-      line,
-      lineText: state.doc.slice(lineStart, lineEnd),
-      namespace: 'file',
-      suggestion: ''
-    },
+    location,
     notes: [],
     pluginName: state.name,
-    text: message.reason
+    text
   }
 }

packages/esbuild/test/index.js

@@ -231,7 +231,7 @@ test('@mdx-js/esbuild', async function (t) {
         },
         notes: [],
         pluginName: '@mdx-js/esbuild',
-        text: 'Unexpected character `/` (U+002F) before local name, expected a character that can start a name, such as a letter, `$`, or `_` (note: to create a link in MDX, use `[text](url)`)'
+        text: 'Cannot process MDX file with esbuild:\n  1:12: Unexpected character `/` (U+002F) before local name, expected a character that can start a name, such as a letter, `$`, or `_` (note: to create a link in MDX, use `[text](url)`)'
       })
     }
 
@@ -271,7 +271,7 @@ test('@mdx-js/esbuild', async function (t) {
             location: {
               column: 20,
               file: 'test/esbuild.mdx',
-              length: 1,
+              length: 0,
               line: 3,
               lineText: '# Hello, <Message />',
               namespace: 'file',
@@ -290,7 +290,7 @@ test('@mdx-js/esbuild', async function (t) {
               file: 'test/esbuild.mdx',
               length: 0,
               line: 0,
-              lineText: 'export function Message() { return <>World!</> }',
+              lineText: '',
               namespace: 'file',
               suggestion: ''
             },
@@ -305,7 +305,7 @@ test('@mdx-js/esbuild', async function (t) {
               file: 'test/esbuild.mdx',
               length: 0,
               line: 0,
-              lineText: 'export function Message() { return <>World!</> }',
+              lineText: '',
               namespace: 'file',
               suggestion: ''
             },
@@ -365,7 +365,7 @@ test('@mdx-js/esbuild', async function (t) {
               file: 'test/esbuild.mdx',
               length: 11,
               line: 3,
-              lineText: '# Hello, <Message />',
+              lineText: '',
               namespace: 'file',
               suggestion: ''
             },
@@ -414,7 +414,10 @@ test('@mdx-js/esbuild', async function (t) {
         file.message('3', tree)
         file.message('4', esm)
         file.message('5', text)
-        file.message('6', jsx)
+        const m6 = file.message('6', jsx)
+        assert(m6.place)
+        assert('start' in m6.place)
+        delete m6.place.start.offset
         file.message('7', head.position.end).fatal = true // End of heading
       }
     }
@@ -439,10 +442,6 @@ test('@mdx-js/esbuild', async function (t) {
       /** @type {BuildFailure} */
       const result = JSON.parse(JSON.stringify(error))
 
-      for (const message of [...result.errors, ...result.warnings]) {
-        message.text = message.text.split('\n')[0]
-      }
-
       assert.deepEqual(result, {
         errors: [
           {
@@ -461,13 +460,13 @@ test('@mdx-js/esbuild', async function (t) {
               file: 'test/esbuild.mdx',
               length: 0,
               line: 0,
-              lineText: '# hi',
+              lineText: '',
               namespace: 'file',
               suggestion: ''
             },
             notes: [],
             pluginName: '@mdx-js/esbuild',
-            text: 'Cannot process MDX file with esbuild'
+            text: 'Cannot process MDX file with esbuild:\n  Error: Something went wrong'
           }
         ],
         warnings: []