module: show user location for missing module errors, resolve #38892

lib/internal/errors/error_source.js

@@ -2,6 +2,11 @@
 
 const {
   FunctionPrototypeBind,
+  MathMax,
+  MathMin,
+  NumberIsFinite,
+  RegExpPrototypeSymbolReplace,
+  StringPrototypeRepeat,
   StringPrototypeSlice,
 } = primordials;
 
@@ -14,6 +19,80 @@ const {
   getSourceLine,
 } = require('internal/source_map/source_map_cache');
 
+const kSourceLineMaxLength = 120;
+const kSourceLineContext = 40;
+const kLineEllipsis = '...';
+
+function createSourceUnderline(sourceLine, startColumn, underlineLength) {
+  const prefix = RegExpPrototypeSymbolReplace(
+    /[^\t]/g, StringPrototypeSlice(sourceLine, 0, startColumn), ' ');
+  return prefix + StringPrototypeRepeat('^', underlineLength);
+}
+
+function clipSourceLine(sourceLine, startColumn, underlineLength) {
+  if (sourceLine.length <= kSourceLineMaxLength) {
+    return {
+      sourceLine,
+      startColumn,
+      underlineLength,
+    };
+  }
+
+  const targetEnd = startColumn + underlineLength;
+  const windowStart = MathMax(0, startColumn - kSourceLineContext);
+  const windowEnd = MathMin(
+    sourceLine.length,
+    windowStart + kSourceLineMaxLength,
+    targetEnd + kSourceLineContext,
+  );
+
+  const leftEllipsis = windowStart > 0 ? kLineEllipsis : '';
+  const rightEllipsis = windowEnd < sourceLine.length ? kLineEllipsis : '';
+  const clippedLine = leftEllipsis +
+    StringPrototypeSlice(sourceLine, windowStart, windowEnd) +
+    rightEllipsis;
+  const clippedStartColumn = leftEllipsis.length + startColumn - windowStart;
+  const clippedUnderlineLength = MathMax(
+    1,
+    MathMin(underlineLength, windowEnd - startColumn),
+  );
+
+  return {
+    sourceLine: clippedLine,
+    startColumn: clippedStartColumn,
+    underlineLength: clippedUnderlineLength,
+  };
+}
+
+/**
+ * Format a source line with a caret underline for an error message.
+ * @param {string} filename The file containing the source line.
+ * @param {number} lineNumber The 1-based line number.
+ * @param {string} sourceLine The source line text.
+ * @param {number} startColumn The 0-based underline start column.
+ * @param {number} underlineLength The underline length.
+ * @returns {string|undefined}
+ */
+function getErrorSourceMessage(filename, lineNumber, sourceLine, startColumn, underlineLength) {
+  if (typeof sourceLine !== 'string' ||
+      !NumberIsFinite(lineNumber) ||
+      !NumberIsFinite(startColumn) ||
+      !NumberIsFinite(underlineLength)) {
+    return;
+  }
+
+  startColumn = MathMax(0, startColumn);
+  underlineLength = MathMax(1, underlineLength);
+
+  const clipped = clipSourceLine(sourceLine, startColumn, underlineLength);
+  const arrow = createSourceUnderline(
+    clipped.sourceLine,
+    clipped.startColumn,
+    clipped.underlineLength,
+  );
+  return `${filename}:${lineNumber}\n${clipped.sourceLine}\n${arrow}\n`;
+}
+
 /**
  * Get the source location of an error. If source map is enabled, resolve the source location
  * based on the source map.
@@ -162,4 +241,5 @@ function getErrorSourceExpression(error) {
 module.exports = {
   getErrorSourceLocation,
   getErrorSourceExpression,
+  getErrorSourceMessage,
 };

lib/internal/modules/cjs/loader.js

@@ -38,6 +38,7 @@ const {
   Error,
   FunctionPrototypeCall,
   JSONParse,
+  Number,
   ObjectDefineProperty,
   ObjectFreeze,
   ObjectGetOwnPropertyDescriptor,
@@ -57,7 +58,6 @@ const {
   StringPrototypeCharCodeAt,
   StringPrototypeEndsWith,
   StringPrototypeIndexOf,
-  StringPrototypeRepeat,
   StringPrototypeSlice,
   StringPrototypeSplit,
   StringPrototypeStartsWith,
@@ -142,6 +142,7 @@ const {
   kEmptyObject,
   setOwnProperty,
   getLazy,
+  getStructuredStack,
   isWindows,
   isUnderNodeModules,
 } = require('internal/util');
@@ -183,6 +184,8 @@ const { stripTypeScriptModuleTypes } = require('internal/modules/typescript');
 const packageJsonReader = require('internal/modules/package_json_reader');
 const { getOptionValue, getEmbedderOptions } = require('internal/options');
 const shouldReportRequiredModules = getLazy(() => process.env.WATCH_REPORT_DEPENDENCIES);
+const lazyGetErrorSourceMessage =
+  getLazy(() => require('internal/errors/error_source').getErrorSourceMessage);
 
 const {
   vm_dynamic_import_default_internal,
@@ -1475,6 +1478,7 @@ Module._resolveFilename = function(request, parent, isMain, options) {
   const err = new Error(message);
   err.code = 'MODULE_NOT_FOUND';
   err.requireStack = requireStack;
+  decorateModuleNotFoundError(err, requireStack, request);
   throw err;
 };
 
@@ -1518,6 +1522,60 @@ function createEsmNotFoundErr(request, path) {
   return err;
 }
 
+function decorateModuleNotFoundError(err, requireStack, request) {
+  const parentPath = requireStack[0];
+  if (!parentPath || StringPrototypeIndexOf(parentPath, path.sep) === -1) {
+    return;
+  }
+
+  const stack = getStructuredStack();
+  let line;
+  let col;
+  for (let i = 0; i < stack.length; i++) {
+    const frame = stack[i];
+    if (frame.getFileName() === parentPath) {
+      line = frame.getLineNumber();
+      col = frame.getColumnNumber();
+      break;
+    }
+  }
+
+  if (!line || !col) {
+    return;
+  }
+
+  let source;
+  try {
+    source = fs.readFileSync(parentPath, 'utf8');
+  } catch {
+    return;
+  }
+
+  const sourceLine = StringPrototypeSplit(source, '\n', line)[line - 1];
+  if (sourceLine === undefined) {
+    return;
+  }
+
+  let column = StringPrototypeIndexOf(sourceLine, request, col - 1);
+  if (column === -1) {
+    column = StringPrototypeIndexOf(sourceLine, request);
+  }
+  if (column === -1) {
+    column = col - 1;
+  }
+
+  const message = lazyGetErrorSourceMessage()(
+    parentPath,
+    Number(line),
+    sourceLine,
+    column,
+    request.length,
+  );
+  if (message !== undefined) {
+    setArrowMessage(err, message);
+  }
+}
+
 function getExtensionForFormat(format) {
   switch (format) {
     case 'addon':
@@ -1879,8 +1937,11 @@ function reconstructErrorStack(err, parentPath, parentSource) {
     RegExpPrototypeExec(/(\d+):(\d+)\)/, errLine) || [];
   if (line && col) {
     const srcLine = StringPrototypeSplit(parentSource, '\n', line)[line - 1];
-    const frame = `${parentPath}:${line}\n${srcLine}\n${StringPrototypeRepeat(' ', col - 1)}^\n`;
-    setArrowMessage(err, frame);
+    const message = lazyGetErrorSourceMessage()(
+      parentPath, Number(line), srcLine, col - 1, 1);
+    if (message !== undefined) {
+      setArrowMessage(err, message);
+    }
   }
 }
 

lib/internal/modules/esm/loader.js

@@ -6,10 +6,15 @@ const {
   ArrayPrototypeReduce,
   FunctionPrototypeCall,
   JSONStringify,
+  Number,
   ObjectSetPrototypeOf,
   Promise,
   PromisePrototypeThen,
+  RegExpPrototypeExec,
   RegExpPrototypeSymbolReplace,
+  StringPrototypeIndexOf,
+  StringPrototypeSplit,
+  StringPrototypeStartsWith,
   encodeURIComponent,
   hardenRegExp,
 } = primordials;
@@ -24,16 +29,21 @@ const { imported_cjs_symbol } = internalBinding('symbols');
 
 const assert = require('internal/assert');
 const {
-  ERR_REQUIRE_ASYNC_MODULE,
-  ERR_REQUIRE_CYCLE_MODULE,
-  ERR_REQUIRE_ESM,
-  ERR_REQUIRE_ESM_RACE_CONDITION,
-  ERR_UNKNOWN_MODULE_FORMAT,
-} = require('internal/errors').codes;
+  codes: {
+    ERR_REQUIRE_ASYNC_MODULE,
+    ERR_REQUIRE_CYCLE_MODULE,
+    ERR_REQUIRE_ESM,
+    ERR_REQUIRE_ESM_RACE_CONDITION,
+    ERR_UNKNOWN_MODULE_FORMAT,
+  },
+  setArrowMessage,
+} = require('internal/errors');
 const { getOptionValue } = require('internal/options');
 const { isURL, pathToFileURL } = require('internal/url');
+const { readFileSync } = require('fs');
 const {
   getDeprecationWarningEmitter,
+  getLazy,
   kEmptyObject,
 } = require('internal/util');
 const {
@@ -78,6 +88,83 @@ let debug = require('internal/util/debuglog').debuglog('esm', (fn) => {
 });
 
 const { isPromise } = require('internal/util/types');
+const lazyGetErrorSourceMessage =
+  getLazy(() => require('internal/errors/error_source').getErrorSourceMessage);
+
+function getOrCreateModuleJobWithStackTraceLimit(loader, parentURL, request, limit) {
+  const originalLimit = Error.stackTraceLimit;
+  try {
+    if (originalLimit < limit) {
+      Error.stackTraceLimit = limit;
+    }
+    return loader.getOrCreateModuleJob(parentURL, request);
+  } finally {
+    Error.stackTraceLimit = originalLimit;
+  }
+}
+
+function decorateDynamicImportModuleNotFoundError(error, parentURL, specifier) {
+  if (error?.code !== 'ERR_MODULE_NOT_FOUND' ||
+      typeof parentURL !== 'string' ||
+      !StringPrototypeStartsWith(parentURL, 'file://')) {
+    return;
+  }
+
+  let filename;
+  try {
+    filename = urlToFilename(parentURL);
+  } catch {
+    return;
+  }
+
+  const stackLines = StringPrototypeSplit(error.stack, '\n');
+  let frame;
+  for (let i = 0; i < stackLines.length; i++) {
+    if (StringPrototypeStartsWith(stackLines[i], '    at ') &&
+        (StringPrototypeIndexOf(stackLines[i], parentURL) !== -1 ||
+         StringPrototypeIndexOf(stackLines[i], filename) !== -1)) {
+      frame = stackLines[i];
+      break;
+    }
+  }
+
+  const { 1: line, 2: col } =
+    RegExpPrototypeExec(/:(\d+):(\d+)\)?$/, frame) || [];
+  if (!line || !col) {
+    return;
+  }
+
+  let source;
+  try {
+    source = readFileSync(filename, 'utf8');
+  } catch {
+    return;
+  }
+
+  const sourceLine = StringPrototypeSplit(source, '\n', line)[line - 1];
+  if (sourceLine === undefined) {
+    return;
+  }
+
+  let column = StringPrototypeIndexOf(sourceLine, specifier, col - 1);
+  if (column === -1) {
+    column = StringPrototypeIndexOf(sourceLine, specifier);
+  }
+  if (column === -1) {
+    column = col - 1;
+  }
+
+  const message = lazyGetErrorSourceMessage()(
+    filename,
+    Number(line),
+    sourceLine,
+    column,
+    specifier.length,
+  );
+  if (message !== undefined) {
+    setArrowMessage(error, message);
+  }
+}
 
 /**
  * @typedef {import('./hooks.js').AsyncLoaderHookWorker} AsyncLoaderHookWorker
@@ -612,11 +699,16 @@ class ModuleLoader {
       const request = { specifier, phase, attributes: importAttributes, __proto__: null };
       let moduleJob;
       try {
-        moduleJob = await this.getOrCreateModuleJob(parentURL, request);
+        const maybeModuleJob =
+          typeof parentURL === 'string' && StringPrototypeStartsWith(parentURL, 'file://') ?
+            getOrCreateModuleJobWithStackTraceLimit(this, parentURL, request, 100) :
+            this.getOrCreateModuleJob(parentURL, request);
+        moduleJob = await maybeModuleJob;
       } catch (e) {
         if (e?.code === 'ERR_ASYNC_LOADER_REQUEST_NEVER_SETTLED') {
           return new Promise(() => {});
         }
+        decorateDynamicImportModuleNotFoundError(e, parentURL, specifier);
         throw e;
       }
       if (phase === kSourcePhase) {