Merge pull request #1212 from rollup/gh-545

[WIP] [BREAKING] More consistent error logging, with code frames etc

bin/src/handleError.js

@@ -1,65 +0,0 @@
-import chalk from 'chalk';
-
-function stderr ( msg ) {
-	console.error( msg ); // eslint-disable-line no-console
-}
-
-const handlers = {
-	MISSING_CONFIG: () => {
-		stderr( chalk.red( 'Config file must export an options object. See https://github.com/rollup/rollup/wiki/Command-Line-Interface#using-a-config-file' ) );
-	},
-
-	MISSING_EXTERNAL_CONFIG: err => {
-		stderr( chalk.red( `Could not resolve config file ${err.config}` ) );
-	},
-
-	MISSING_INPUT_OPTION: () => {
-		stderr( chalk.red( 'You must specify an --input (-i) option' ) );
-	},
-
-	MISSING_OUTPUT_OPTION: () => {
-		stderr( chalk.red( 'You must specify an --output (-o) option when creating a file with a sourcemap' ) );
-	},
-
-	MISSING_NAME: () => {
-		stderr( chalk.red( 'You must supply a name for UMD exports (e.g. `--name myModule`)' ) );
-	},
-
-	PARSE_ERROR: err => {
-		stderr( chalk.red( `Error parsing ${err.file}: ${err.message}` ) );
-	},
-
-	ONE_AT_A_TIME: () => {
-		stderr( chalk.red( 'rollup can only bundle one file at a time' ) );
-	},
-
-	DUPLICATE_IMPORT_OPTIONS: () => {
-		stderr( chalk.red( 'use --input, or pass input path as argument' ) );
-	},
-
-	ROLLUP_WATCH_NOT_INSTALLED: () => {
-		stderr( chalk.red( 'rollup --watch depends on the rollup-watch package, which could not be found. Install it with ' ) + chalk.cyan( 'npm install -D rollup-watch' ) );
-	},
-
-	WATCHER_MISSING_INPUT_OR_OUTPUT: () => {
-		stderr( chalk.red( 'must specify --input and --output when using rollup --watch' ) );
-	}
-};
-
-export default function handleError ( err, recover ) {
-	const handler = handlers[ err && err.code ];
-
-	if ( handler ) {
-		handler( err );
-	} else {
-		stderr( chalk.red( err.message || err ) );
-
-		if ( err.stack ) {
-			stderr( chalk.grey( err.stack ) );
-		}
-	}
-
-	stderr( `Type ${chalk.cyan( 'rollup --help' )} for help, or visit https://github.com/rollup/rollup/wiki` );
-
-	if ( !recover ) process.exit( 1 );
-}

bin/src/logging.js

@@ -0,0 +1,47 @@
+import chalk from 'chalk';
+import relativeId from '../../src/utils/relativeId.js';
+
+if ( !process.stderr.isTTY ) chalk.enabled = false;
+const warnSymbol = process.stderr.isTTY ? `⚠️   ` : `Warning: `;
+const errorSymbol = process.stderr.isTTY ? `🚨   ` : `Error: `;
+
+// log to stderr to keep `rollup main.js > bundle.js` from breaking
+export const stderr = console.error.bind( console ); // eslint-disable-line no-console
+
+export function handleWarning ( warning ) {
+	stderr( `${warnSymbol}${chalk.bold( warning.message )}` );
+
+	if ( warning.url ) {
+		stderr( chalk.cyan( warning.url ) );
+	}
+
+	if ( warning.loc ) {
+		stderr( `${relativeId( warning.loc.file )} (${warning.loc.line}:${warning.loc.column})` );
+	}
+
+	if ( warning.frame ) {
+		stderr( chalk.dim( warning.frame ) );
+	}
+
+	stderr( '' );
+}
+
+export function handleError ( err, recover ) {
+	stderr( `${errorSymbol}${chalk.bold( err.message )}` );
+
+	if ( err.url ) {
+		stderr( chalk.cyan( err.url ) );
+	}
+
+	if ( err.loc ) {
+		stderr( `${relativeId( err.loc.file )} (${err.loc.line}:${err.loc.column})` );
+	}
+
+	if ( err.frame ) {
+		stderr( chalk.dim( err.frame ) );
+	}
+
+	stderr( '' );
+
+	if ( !recover ) process.exit( 1 );
+}

bin/src/runRollup.js

@@ -2,27 +2,26 @@ import { realpathSync } from 'fs';
 import * as rollup from 'rollup';
 import relative from 'require-relative';
 import chalk from 'chalk';
-import handleError from './handleError';
-import relativeId from '../../src/utils/relativeId.js';
+import { handleWarning, handleError, stderr } from './logging.js';
 import SOURCEMAPPING_URL from './sourceMappingUrl.js';
 
 import { install as installSourcemapSupport } from 'source-map-support';
 installSourcemapSupport();
 
-if ( !process.stderr.isTTY ) chalk.enabled = false;
-const warnSymbol = process.stderr.isTTY ? `⚠️   ` : `Warning: `;
-
-// stderr to stderr to keep `rollup main.js > bundle.js` from breaking
-const stderr = console.error.bind( console ); // eslint-disable-line no-console
-
 export default function runRollup ( command ) {
 	if ( command._.length > 1 ) {
-		handleError({ code: 'ONE_AT_A_TIME' });
+		handleError({
+			code: 'ONE_AT_A_TIME',
+			message: 'rollup can only bundle one file at a time'
+		});
 	}
 
 	if ( command._.length === 1 ) {
 		if ( command.input ) {
-			handleError({ code: 'DUPLICATE_IMPORT_OPTIONS' });
+			handleError({
+				code: 'DUPLICATE_IMPORT_OPTIONS',
+				message: 'use --input, or pass input path as argument'
+			});
 		}
 
 		command.input = command._[0];
@@ -51,7 +50,10 @@ export default function runRollup ( command ) {
 					config = relative.resolve( pkgName, process.cwd() );
 				} catch ( err ) {
 					if ( err.code === 'MODULE_NOT_FOUND' ) {
-						handleError({ code: 'MISSING_EXTERNAL_CONFIG', config });
+						handleError({
+							code: 'MISSING_EXTERNAL_CONFIG',
+							message: `Could not resolve config file ${config}`
+						});
 					}
 
 					throw err;
@@ -64,37 +66,38 @@ export default function runRollup ( command ) {
 
 		rollup.rollup({
 			entry: config,
-			onwarn: message => {
-				if ( message.code === 'UNRESOLVED_IMPORT' ) return;
-				stderr( message.toString() );
+			onwarn: warning => {
+				if ( warning.code === 'UNRESOLVED_IMPORT' ) return;
+				handleWarning( warning );
 			}
-		}).then( bundle => {
-			const { code } = bundle.generate({
-				format: 'cjs'
-			});
+		})
+			.then( bundle => {
+				const { code } = bundle.generate({
+					format: 'cjs'
+				});
 
-			// temporarily override require
-			const defaultLoader = require.extensions[ '.js' ];
-			require.extensions[ '.js' ] = ( m, filename ) => {
-				if ( filename === config ) {
-					m._compile( code, filename );
-				} else {
-					defaultLoader( m, filename );
-				}
-			};
+				// temporarily override require
+				const defaultLoader = require.extensions[ '.js' ];
+				require.extensions[ '.js' ] = ( m, filename ) => {
+					if ( filename === config ) {
+						m._compile( code, filename );
+					} else {
+						defaultLoader( m, filename );
+					}
+				};
 
-			try {
 				const options = require( config );
 				if ( Object.keys( options ).length === 0 ) {
-					handleError({ code: 'MISSING_CONFIG' });
+					handleError({
+						code: 'MISSING_CONFIG',
+						message: 'Config file must export an options object',
+						url: 'https://github.com/rollup/rollup/wiki/Command-Line-Interface#using-a-config-file'
+					});
 				}
 				execute( options, command );
 				require.extensions[ '.js' ] = defaultLoader;
-			} catch ( err ) {
-				handleError( err );
-			}
-		})
-		.catch( stderr );
+			})
+			.catch( handleError );
 	} else {
 		execute( {}, command );
 	}
@@ -157,21 +160,7 @@ function execute ( options, command ) {
 			if ( seen.has( str ) ) return;
 			seen.add( str );
 
-			stderr( `${warnSymbol}${chalk.bold( warning.message )}` );
-
-			if ( warning.url ) {
-				stderr( chalk.cyan( warning.url ) );
-			}
-
-			if ( warning.loc ) {
-				stderr( `${relativeId( warning.loc.file )} (${warning.loc.line}:${warning.loc.column})` );
-			}
-
-			if ( warning.frame ) {
-				stderr( chalk.dim( warning.frame ) );
-			}
-
-			stderr( '' );
+			handleWarning( warning );
 		};
 	}
 
@@ -184,50 +173,52 @@ function execute ( options, command ) {
 		}
 	});
 
-	try {
-		if ( command.watch ) {
-			if ( !options.entry || ( !options.dest && !options.targets ) ) {
-				handleError({ code: 'WATCHER_MISSING_INPUT_OR_OUTPUT' });
-			}
+	if ( command.watch ) {
+		if ( !options.entry || ( !options.dest && !options.targets ) ) {
+			handleError({
+				code: 'WATCHER_MISSING_INPUT_OR_OUTPUT',
+				message: 'must specify --input and --output when using rollup --watch'
+			});
+		}
 
-			try {
-				const watch = relative( 'rollup-watch', process.cwd() );
-				const watcher = watch( rollup, options );
+		try {
+			const watch = relative( 'rollup-watch', process.cwd() );
+			const watcher = watch( rollup, options );
 
-				watcher.on( 'event', event => {
-					switch ( event.code ) {
-						case 'STARTING': // TODO this isn't emitted by newer versions of rollup-watch
-							stderr( 'checking rollup-watch version...' );
-							break;
+			watcher.on( 'event', event => {
+				switch ( event.code ) {
+					case 'STARTING': // TODO this isn't emitted by newer versions of rollup-watch
+						stderr( 'checking rollup-watch version...' );
+						break;
 
-						case 'BUILD_START':
-							stderr( 'bundling...' );
-							break;
+					case 'BUILD_START':
+						stderr( 'bundling...' );
+						break;
 
-						case 'BUILD_END':
-							stderr( 'bundled in ' + event.duration + 'ms. Watching for changes...' );
-							break;
+					case 'BUILD_END':
+						stderr( 'bundled in ' + event.duration + 'ms. Watching for changes...' );
+						break;
 
-						case 'ERROR':
-							handleError( event.error, true );
-							break;
+					case 'ERROR':
+						handleError( event.error, true );
+						break;
 
-						default:
-							stderr( 'unknown event', event );
-					}
-				});
-			} catch ( err ) {
-				if ( err.code === 'MODULE_NOT_FOUND' ) {
-					err.code = 'ROLLUP_WATCH_NOT_INSTALLED';
+					default:
+						stderr( 'unknown event', event );
 				}
-
-				handleError( err );
+			});
+		} catch ( err ) {
+			if ( err.code === 'MODULE_NOT_FOUND' ) {
+				handleError({
+					code: 'ROLLUP_WATCH_NOT_INSTALLED',
+					message: 'rollup --watch depends on the rollup-watch package, which could not be found. Install it with npm install -D rollup-watch'
+				});
 			}
-		} else {
-			bundle( options ).catch( handleError );
+
+			handleError( err );
 		}
-	} catch ( err ) {
-		handleError( err );
+	} else {
+		bundle( options ).catch( handleError );
 	}
 }
 
@@ -244,34 +235,42 @@ function assign ( target, source ) {
 
 function bundle ( options ) {
 	if ( !options.entry ) {
-		handleError({ code: 'MISSING_INPUT_OPTION' });
+		handleError({
+			code: 'MISSING_INPUT_OPTION',
+			message: 'You must specify an --input (-i) option'
+		});
 	}
 
-	return rollup.rollup( options ).then( bundle => {
-		if ( options.dest ) {
-			return bundle.write( options );
-		}
+	return rollup.rollup( options )
+		.then( bundle => {
+			if ( options.dest ) {
+				return bundle.write( options );
+			}
 
-		if ( options.targets ) {
-			let result = null;
+			if ( options.targets ) {
+				let result = null;
 
-			options.targets.forEach( target => {
-				result = bundle.write( assign( clone( options ), target ) );
-			});
+				options.targets.forEach( target => {
+					result = bundle.write( assign( clone( options ), target ) );
+				});
 
-			return result;
-		}
+				return result;
+			}
 
-		if ( options.sourceMap && options.sourceMap !== 'inline' ) {
-			handleError({ code: 'MISSING_OUTPUT_OPTION' });
-		}
+			if ( options.sourceMap && options.sourceMap !== 'inline' ) {
+				handleError({
+					code: 'MISSING_OUTPUT_OPTION',
+					message: 'You must specify an --output (-o) option when creating a file with a sourcemap'
+				});
+			}
 
-		let { code, map } = bundle.generate( options );
+			let { code, map } = bundle.generate( options );
 
-		if ( options.sourceMap === 'inline' ) {
-			code += `\n//# ${SOURCEMAPPING_URL}=${map.toUrl()}\n`;
-		}
+			if ( options.sourceMap === 'inline' ) {
+				code += `\n//# ${SOURCEMAPPING_URL}=${map.toUrl()}\n`;
+			}
 
-		process.stdout.write( code );
-	});
+			process.stdout.write( code );
+		})
+		.catch( handleError );
 }

src/Bundle.js

@@ -17,6 +17,7 @@ import transformBundle from './utils/transformBundle.js';
 import collapseSourcemaps from './utils/collapseSourcemaps.js';
 import callIfFunction from './utils/callIfFunction.js';
 import relativeId from './utils/relativeId.js';
+import error from './utils/error.js';
 import { dirname, isRelative, isAbsolute, normalize, relative, resolve } from './utils/path.js';
 import BundleScope from './ast/scopes/BundleScope.js';
 
@@ -106,7 +107,13 @@ export default class Bundle {
 		// of the entry module's dependencies
 		return this.resolveId( this.entry, undefined )
 			.then( id => {
-				if ( id == null ) throw new Error( `Could not resolve entry (${this.entry})` );
+				if ( id == null ) {
+					error({
+						code: 'UNRESOLVED_ENTRY',
+						message: `Could not resolve entry (${this.entry})`
+					});
+				}
+
 				this.entryId = id;
 				return this.fetchModule( id, undefined );
 			})
@@ -268,7 +275,11 @@ export default class Bundle {
 				if ( typeof source === 'string' ) return source;
 				if ( source && typeof source === 'object' && source.code ) return source;
 
-				throw new Error( `Error loading ${id}: load hook should return a string, a { code, map } object, or nothing/null` );
+				// TODO report which plugin failed
+				error({
+					code: 'BAD_LOADER',
+					message: `Error loading ${relativeId( id )}: plugin load hook should return a string, a { code, map } object, or nothing/null`
+				});
 			})
 			.then( source => {
 				if ( typeof source === 'string' ) {
@@ -337,7 +348,12 @@ export default class Bundle {
 					let isExternal = this.isExternal( externalId );
 
 					if ( !resolvedId && !isExternal ) {
-						if ( isRelative( source ) ) throw new Error( `Could not resolve '${source}' from ${module.id}` );
+						if ( isRelative( source ) ) {
+							error({
+								code: 'UNRESOLVED_IMPORT',
+								message: `Could not resolve '${source}' from ${relativeId( module.id )}`
+							});
+						}
 
 						this.warn({
 							code: 'UNRESOLVED_IMPORT',
@@ -367,7 +383,20 @@ export default class Bundle {
 						});
 					} else {
 						if ( resolvedId === module.id ) {
-							throw new Error( `A module cannot import itself (${resolvedId})` );
+							// need to find the actual import declaration, so we can provide
+							// a useful error message. Bit hoop-jumpy but what can you do
+							const name = Object.keys( module.imports )
+								.find( name => {
+									const declaration = module.imports[ name ];
+									return declaration.source === source;
+								});
+
+							const declaration = module.imports[ name ].specifier.parent;
+
+							module.error({
+								code: 'CANNOT_IMPORT_SELF',
+								message: `A module cannot import itself`
+							}, declaration.start );
 						}
 
 						module.resolvedIds[ source ] = resolvedId;
@@ -445,7 +474,12 @@ export default class Bundle {
 		const indentString = getIndentString( magicString, options );
 
 		const finalise = finalisers[ options.format ];
-		if ( !finalise ) throw new Error( `You must specify an output type - valid options are ${keys( finalisers ).join( ', ' )}` );
+		if ( !finalise ) {
+			error({
+				code: 'INVALID_OPTION',
+				message: `You must specify an output type - valid options are ${keys( finalisers ).join( ', ' )}`
+			});
+		}
 
 		timeStart( 'render format' );
 

src/Module.js

@@ -15,25 +15,27 @@ import enhance from './ast/enhance.js';
 import clone from './ast/clone.js';
 import ModuleScope from './ast/scopes/ModuleScope.js';
 
-function tryParse ( code, comments, acornOptions, id ) {
+function tryParse ( module, acornOptions ) {
 	try {
-		return parse( code, assign({
+		return parse( module.code, assign({
 			ecmaVersion: 8,
 			sourceType: 'module',
-			onComment: ( block, text, start, end ) => comments.push({ block, text, start, end }),
+			onComment: ( block, text, start, end ) => module.comments.push({ block, text, start, end }),
 			preserveParens: false
 		}, acornOptions ));
 	} catch ( err ) {
-		err.code = 'PARSE_ERROR';
-		err.file = id; // see above - not necessarily true, but true enough
-		err.message += ` in ${id}`;
-		throw err;
+		module.error({
+			code: 'PARSE_ERROR',
+			message: err.message.replace( / \(\d+:\d+\)$/, '' )
+		}, err.pos );
 	}
 }
 
 export default class Module {
 	constructor ({ id, code, originalCode, originalSourceMap, ast, sourceMapChain, resolvedIds, bundle }) {
 		this.code = code;
+		this.id = id;
+		this.bundle = bundle;
 		this.originalCode = originalCode;
 		this.originalSourceMap = originalSourceMap;
 		this.sourceMapChain = sourceMapChain;
@@ -48,14 +50,12 @@ export default class Module {
 			this.ast = clone( ast );
 			this.astClone = ast;
 		} else {
-			this.ast = tryParse( code, this.comments, bundle.acornOptions, id ); // TODO what happens to comments if AST is provided?
+			this.ast = tryParse( this, bundle.acornOptions ); // TODO what happens to comments if AST is provided?
 			this.astClone = clone( this.ast );
 		}
 
 		timeEnd( 'ast' );
 
-		this.bundle = bundle;
-		this.id = id;
 		this.excludeFromSourcemap = /\0/.test( id );
 		this.context = bundle.getModuleContext( id );
 
@@ -121,7 +121,10 @@ export default class Module {
 					const name = specifier.exported.name;
 
 					if ( this.exports[ name ] || this.reexports[ name ] ) {
-						throw new Error( `A module cannot have multiple exports with the same name ('${name}')` );
+						this.error({
+							code: 'DUPLICATE_EXPORT',
+							message: `A module cannot have multiple exports with the same name ('${name}')`
+						}, specifier.start );
 					}
 
 					this.reexports[ name ] = {
@@ -141,8 +144,10 @@ export default class Module {
 			const identifier = ( node.declaration.id && node.declaration.id.name ) || node.declaration.name;
 
 			if ( this.exports.default ) {
-				// TODO indicate location
-				throw new Error( 'A module can only have one default export' );
+				this.error({
+					code: 'DUPLICATE_EXPORT',
+					message: `A module can only have one default export`
+				}, node.start );
 			}
 
 			this.exports.default = {
@@ -182,7 +187,10 @@ export default class Module {
 					const exportedName = specifier.exported.name;
 
 					if ( this.exports[ exportedName ] || this.reexports[ exportedName ] ) {
-						throw new Error( `A module cannot have multiple exports with the same name ('${exportedName}')` );
+						this.error({
+							code: 'DUPLICATE_EXPORT',
+							message: `A module cannot have multiple exports with the same name ('${exportedName}')`
+						}, specifier.start );
 					}
 
 					this.exports[ exportedName ] = { localName };
@@ -207,10 +215,10 @@ export default class Module {
 			const localName = specifier.local.name;
 
 			if ( this.imports[ localName ] ) {
-				const err = new Error( `Duplicated import '${localName}'` );
-				err.file = this.id;
-				err.loc = locate( this.code, specifier.start, { offsetLine: 1 });
-				throw err;
+				this.error({
+					code: 'DUPLICATE_IMPORT',
+					message: `Duplicated import '${localName}'`
+				}, specifier.start );
 			}
 
 			const isDefault = specifier.type === 'ImportDefaultSpecifier';
@@ -282,6 +290,19 @@ export default class Module {
 		// }
 	}
 
+	error ( props, pos ) {
+		if ( pos !== undefined ) {
+			props.pos = pos;
+
+			const { line, column } = locate( this.code, pos, { offsetLine: 1 }); // TODO trace sourcemaps
+
+			props.loc = { file: this.id, line, column };
+			props.frame = getCodeFrame( this.code, line, column );
+		}
+
+		error( props );
+	}
+
 	findParent () {
 		// TODO what does it mean if we're here?
 		return null;
@@ -372,11 +393,11 @@ export default class Module {
 			const declaration = otherModule.traceExport( importDeclaration.name );
 
 			if ( !declaration ) {
-				error({
-					message: `'${importDeclaration.name}' is not exported by ${relativeId( otherModule.id )} (imported by ${relativeId( this.id )}). For help fixing this error see https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module`,
-					file: this.id,
-					loc: locate( this.code, importDeclaration.specifier.start, { offsetLine: 1 })
-				});
+				this.error({
+					code: 'MISSING_EXPORT',
+					message: `'${importDeclaration.name}' is not exported by ${relativeId( otherModule.id )}`,
+					url: `https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module`
+				}, importDeclaration.specifier.start );
 			}
 
 			return declaration;
@@ -392,11 +413,11 @@ export default class Module {
 			const declaration = reexportDeclaration.module.traceExport( reexportDeclaration.localName );
 
 			if ( !declaration ) {
-				error({
-					message: `'${reexportDeclaration.localName}' is not exported by '${reexportDeclaration.module.id}' (imported by '${this.id}')`,
-					file: this.id,
-					loc: locate( this.code, reexportDeclaration.start, { offsetLine: 1 })
-				});
+				this.error({
+					code: 'MISSING_EXPORT',
+					message: `'${reexportDeclaration.localName}' is not exported by ${relativeId( reexportDeclaration.module.id )}`,
+					url: `https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module`
+				}, reexportDeclaration.start );
 			}
 
 			return declaration;

src/ast/nodes/CallExpression.js

@@ -1,5 +1,3 @@
-import { locate } from 'locate-character';
-import error from '../../utils/error.js';
 import Node from '../Node.js';
 import isProgramLevel from '../utils/isProgramLevel.js';
 import callHasEffects from './shared/callHasEffects.js';
@@ -10,12 +8,10 @@ export default class CallExpression extends Node {
 			const declaration = scope.findDeclaration( this.callee.name );
 
 			if ( declaration.isNamespace ) {
-				error({
-					message: `Cannot call a namespace ('${this.callee.name}')`,
-					file: this.module.id,
-					pos: this.start,
-					loc: locate( this.module.code, this.start, { offsetLine: 1 })
-				});
+				this.module.error({
+					code: 'CANNOT_CALL_NAMESPACE',
+					message: `Cannot call a namespace ('${this.callee.name}')`
+				}, this.start );
 			}
 
 			if ( this.callee.name === 'eval' && declaration.isGlobal ) {

src/ast/nodes/shared/disallowIllegalReassignment.js

@@ -1,28 +1,21 @@
-import { locate } from 'locate-character';
-import error from '../../../utils/error.js';
-
 // TODO tidy this up a bit (e.g. they can both use node.module.imports)
 export default function disallowIllegalReassignment ( scope, node ) {
 	if ( node.type === 'MemberExpression' && node.object.type === 'Identifier' ) {
 		const declaration = scope.findDeclaration( node.object.name );
 		if ( declaration.isNamespace ) {
-			error({
-				message: `Illegal reassignment to import '${node.object.name}'`,
-				file: node.module.id,
-				pos: node.start,
-				loc: locate( node.module.code, node.start, { offsetLine: 1 })
-			});
+			node.module.error({
+				code: 'ILLEGAL_NAMESPACE_REASSIGNMENT',
+				message: `Illegal reassignment to import '${node.object.name}'`
+			}, node.start );
 		}
 	}
 
 	else if ( node.type === 'Identifier' ) {
 		if ( node.module.imports[ node.name ] && !scope.contains( node.name ) ) {
-			error({
-				message: `Illegal reassignment to import '${node.name}'`,
-				file: node.module.id,
-				pos: node.start,
-				loc: locate( node.module.code, node.start, { offsetLine: 1 })
-			});
+			node.module.error({
+				code: 'ILLEGAL_REASSIGNMENT',
+				message: `Illegal reassignment to import '${node.name}'`
+			}, node.start );
 		}
 	}
 }

src/finalisers/iife.js

@@ -1,5 +1,6 @@
 import { blank } from '../utils/object.js';
 import { getName } from '../utils/map-helpers.js';
+import error from '../utils/error.js';
 import getInteropBlock from './shared/getInteropBlock.js';
 import getExportBlock from './shared/getExportBlock.js';
 import getGlobalNameMaker from './shared/getGlobalNameMaker.js';
@@ -36,7 +37,10 @@ export default function iife ( bundle, magicString, { exportMode, indentString,
 	const args = bundle.externalModules.map( getName );
 
 	if ( exportMode !== 'none' && !name ) {
-		throw new Error( 'You must supply options.moduleName for IIFE bundles' );
+		error({
+			code: 'INVALID_OPTION',
+			message: `You must supply options.moduleName for IIFE bundles`
+		});
 	}
 
 	if ( exportMode === 'named' ) {

src/finalisers/umd.js

@@ -1,5 +1,6 @@
 import { blank } from '../utils/object.js';
 import { getName, quotePath, req } from '../utils/map-helpers.js';
+import error from '../utils/error.js';
 import getInteropBlock from './shared/getInteropBlock.js';
 import getExportBlock from './shared/getExportBlock.js';
 import getGlobalNameMaker from './shared/getGlobalNameMaker.js';
@@ -28,7 +29,10 @@ const wrapperOutro = '\n\n})));';
 
 export default function umd ( bundle, magicString, { exportMode, indentString, intro, outro }, options ) {
 	if ( exportMode !== 'none' && !options.moduleName ) {
-		throw new Error( 'You must supply options.moduleName for UMD bundles' );
+		error({
+			code: 'INVALID_OPTION',
+			message: 'You must supply options.moduleName for UMD bundles'
+		});
 	}
 
 	warnOnBuiltins( bundle );

src/rollup.js

@@ -4,6 +4,7 @@ import { writeFile } from './utils/fs.js';
 import { assign, keys } from './utils/object.js';
 import { mapSequence } from './utils/promise.js';
 import validateKeys from './utils/validateKeys.js';
+import error from './utils/error.js';
 import { SOURCEMAPPING_URL } from './utils/sourceMappingURL.js';
 import Bundle from './Bundle.js';
 
@@ -50,15 +51,15 @@ function checkOptions ( options ) {
 		return new Error( 'The `transform`, `load`, `resolveId` and `resolveExternal` options are deprecated in favour of a unified plugin API. See https://github.com/rollup/rollup/wiki/Plugins for details' );
 	}
 
-	const error = validateKeys( keys(options), ALLOWED_KEYS );
-	if ( error ) return error;
+	const err = validateKeys( keys(options), ALLOWED_KEYS );
+	if ( err ) return err;
 
 	return null;
 }
 
 export function rollup ( options ) {
-	const error = checkOptions ( options );
-	if ( error ) return Promise.reject( error );
+	const err = checkOptions ( options );
+	if ( err ) return Promise.reject( err );
 
 	const bundle = new Bundle( options );
 
@@ -105,7 +106,10 @@ export function rollup ( options ) {
 			generate,
 			write: options => {
 				if ( !options || !options.dest ) {
-					throw new Error( 'You must supply options.dest to bundle.write' );
+					error({
+						code: 'MISSING_OPTION',
+						message: 'You must supply options.dest to bundle.write'
+					});
 				}
 
 				const dest = options.dest;

src/utils/collapseSourcemaps.js

@@ -1,4 +1,5 @@
 import { encode } from 'sourcemap-codec';
+import error from './error.js';
 import { dirname, relative, resolve } from './path.js';
 
 class Source {
@@ -51,7 +52,9 @@ class Link {
 					} else if ( sourcesContent[ sourceIndex ] == null ) {
 						sourcesContent[ sourceIndex ] = traced.source.content;
 					} else if ( traced.source.content != null && sourcesContent[ sourceIndex ] !== traced.source.content ) {
-						throw new Error( `Multiple conflicting contents for sourcemap source ${source.filename}` );
+						error({
+							message: `Multiple conflicting contents for sourcemap source ${source.filename}`
+						});
 					}
 
 					segment[1] = sourceIndex;

src/utils/defaults.js

@@ -1,6 +1,7 @@
 import { lstatSync, readdirSync, readFileSync, realpathSync } from './fs.js'; // eslint-disable-line
 import { basename, dirname, isAbsolute, resolve } from './path.js';
 import { blank } from './object.js';
+import error from './error.js';
 
 export function load ( id ) {
 	return readFileSync( id, 'utf-8' );
@@ -27,7 +28,13 @@ function addJsExtensionIfNecessary ( file ) {
 }
 
 export function resolveId ( importee, importer ) {
-	if ( typeof process === 'undefined' ) throw new Error( `It looks like you're using Rollup in a non-Node.js environment. This means you must supply a plugin with custom resolveId and load functions. See https://github.com/rollup/rollup/wiki/Plugins for more information` );
+	if ( typeof process === 'undefined' ) {
+		error({
+			code: 'MISSING_PROCESS',
+			message: `It looks like you're using Rollup in a non-Node.js environment. This means you must supply a plugin with custom resolveId and load functions`,
+			url: 'https://github.com/rollup/rollup/wiki/Plugins'
+		});
+	}
 
 	// absolute paths are left untouched
 	if ( isAbsolute( importee ) ) return addJsExtensionIfNecessary( resolve( importee ) );

src/utils/getCodeFrame.js

@@ -13,12 +13,15 @@ export default function getCodeFrame ( source, line, column ) {
 	let lines = source.split( '\n' );
 
 	const frameStart = Math.max( 0, line - 3 );
-	const frameEnd = Math.min( line + 2, lines.length );
-
-	const digits = String( frameEnd + 1 ).length;
+	let frameEnd = Math.min( line + 2, lines.length );
 
 	lines = lines.slice( frameStart, frameEnd );
-	while ( !/\S/.test( lines[ lines.length - 1 ] ) ) lines.pop();
+	while ( !/\S/.test( lines[ lines.length - 1 ] ) ) {
+		lines.pop();
+		frameEnd -= 1;
+	}
+
+	const digits = String( frameEnd ).length;
 
 	return lines
 		.map( ( str, i ) => {

src/utils/getExportMode.js

@@ -1,7 +1,11 @@
 import { keys } from './object.js';
+import error from './error.js';
 
 function badExports ( option, keys ) {
-	throw new Error( `'${option}' was specified for options.exports, but entry module has following exports: ${keys.join(', ')}` );
+	error({
+		code: 'INVALID_EXPORT_OPTION',
+		message: `'${option}' was specified for options.exports, but entry module has following exports: ${keys.join(', ')}`
+	});
 }
 
 export default function getExportMode ( bundle, {exports: exportMode, moduleName, format} ) {
@@ -35,7 +39,10 @@ export default function getExportMode ( bundle, {exports: exportMode, moduleName
 	}
 
 	if ( !/(?:default|named|none)/.test( exportMode ) ) {
-		throw new Error( `options.exports must be 'default', 'named', 'none', 'auto', or left unspecified (defaults to 'auto')` );
+		error({
+			code: 'INVALID_EXPORT_OPTION',
+			message: `options.exports must be 'default', 'named', 'none', 'auto', or left unspecified (defaults to 'auto')`
+		});
 	}
 
 	return exportMode;

src/utils/transform.js

@@ -1,4 +1,6 @@
 import { decode } from 'sourcemap-codec';
+import error from './error.js';
+import relativeId from './relativeId.js';
 
 export default function transform ( source, id, plugins ) {
 	const sourceMapChain = [];
@@ -11,6 +13,7 @@ export default function transform ( source, id, plugins ) {
 
 	const originalCode = source.code;
 	let ast = source.ast;
+	let errored = false;
 
 	return plugins.reduce( ( promise, plugin ) => {
 		return promise.then( previous => {
@@ -41,15 +44,21 @@ export default function transform ( source, id, plugins ) {
 				return result.code;
 			});
 		}).catch( err => {
-			if ( !err.rollupTransform ) {
-				err.rollupTransform = true;
-				err.id = id;
-				err.plugin = plugin.name;
-				err.message = `Error transforming ${id}${plugin.name ? ` with '${plugin.name}' plugin` : ''}: ${err.message}`;
-			}
+			// TODO this all seems a bit hacky
+			if ( errored ) throw err;
+			errored = true;
+
+			err.plugin = plugin.name;
 			throw err;
 		});
 	}, Promise.resolve( source.code ) )
-
-	.then( code => ({ code, originalCode, originalSourceMap, ast, sourceMapChain }) );
+		.catch( err => {
+			error({
+				code: 'BAD_TRANSFORMER',
+				message: `Error transforming ${relativeId( id )}${err.plugin ? ` with '${err.plugin}' plugin` : ''}: ${err.message}`,
+				plugin: err.plugin,
+				id
+			});
+		})
+		.then( code => ({ code, originalCode, originalSourceMap, ast, sourceMapChain }) );
 }

src/utils/transformBundle.js

@@ -1,4 +1,5 @@
 import { decode } from 'sourcemap-codec';
+import error from './error.js';
 
 export default function transformBundle ( code, plugins, sourceMapChain, options ) {
 	return plugins.reduce( ( code, plugin ) => {
@@ -9,9 +10,11 @@ export default function transformBundle ( code, plugins, sourceMapChain, options
 		try {
 			result = plugin.transformBundle( code, { format : options.format } );
 		} catch ( err ) {
-			err.plugin = plugin.name;
-			err.message = `Error transforming bundle${plugin.name ? ` with '${plugin.name}' plugin` : ''}: ${err.message}`;
-			throw err;
+			error({
+				code: 'BAD_BUNDLE_TRANSFORMER',
+				message: `Error transforming bundle${plugin.name ? ` with '${plugin.name}' plugin` : ''}: ${err.message}`,
+				plugin: plugin.name
+			});
 		}
 
 		if ( result == null ) return code;

test/function/cannot-call-external-namespace/_config.js

@@ -3,10 +3,19 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'errors if code calls an external namespace',
-	error: function ( err ) {
-		assert.equal( err.message, 'Cannot call a namespace (\'foo\')' );
-		assert.equal( err.file.replace( /\//g, path.sep ), path.resolve( __dirname, 'main.js' ) );
-		assert.equal( err.pos, 28 );
-		assert.deepEqual( err.loc, { character: 28, line: 2, column: 0 });
+	error: {
+		code: 'CANNOT_CALL_NAMESPACE',
+		message: `Cannot call a namespace ('foo')`,
+		pos: 28,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 2,
+			column: 0
+		},
+		frame: `
+			1: import * as foo from 'foo';
+			2: foo();
+			   ^
+		`
 	}
 };

test/function/cannot-call-internal-namespace/_config.js

@@ -3,10 +3,19 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'errors if code calls an internal namespace',
-	error: function ( err ) {
-		assert.equal( err.message, 'Cannot call a namespace (\'foo\')' );
-		assert.equal( err.file.replace( /\//g, path.sep ), path.resolve( __dirname, 'main.js' ) );
-		assert.equal( err.pos, 33 );
-		assert.deepEqual( err.loc, { character: 33, line: 2, column: 0 });
+	error: {
+		code: 'CANNOT_CALL_NAMESPACE',
+		message: `Cannot call a namespace ('foo')`,
+		pos: 33,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 2,
+			column: 0
+		},
+		frame: `
+			1: import * as foo from './foo.js';
+			2: foo();
+			   ^
+		`
 	}
 };

test/function/cannot-import-self/_config.js

@@ -1,8 +1,20 @@
+var path = require( 'path' );
 var assert = require( 'assert' );
 
 module.exports = {
 	description: 'prevents a module importing itself',
-	error: function ( err ) {
-		assert.ok( /A module cannot import itself/.test( err.message ) );
+	error: {
+		code: 'CANNOT_IMPORT_SELF',
+		message: `A module cannot import itself`,
+		pos: 0,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 1,
+			column: 0
+		},
+		frame: `
+			1: import me from './main';
+			   ^
+		`
 	}
 };

test/function/check-resolve-for-entry/_config.js

@@ -5,7 +5,8 @@ module.exports = {
 	options: {
 		entry: '/not/a/path/that/actually/really/exists'
 	},
-	error: function ( err ) {
-		assert.ok( /Could not resolve entry/.test( err.message ) );
+	error: {
+		code: 'UNRESOLVED_ENTRY',
+		message: 'Could not resolve entry (/not/a/path/that/actually/really/exists)'
 	}
 };

test/function/custom-path-resolver-plural-b/_config.js

@@ -5,21 +5,21 @@ module.exports = {
 	options: {
 		plugins: [
 			{
-				resolveId: function () {
+				resolveId () {
 					throw new Error( 'nope' );
 				},
-				load: function ( id ) {
+				load ( id ) {
 					if ( id === 'main' ) return 'assert.ok( false );';
 				}
 			},
 			{
-				resolveId: function ( importee, importer ) {
+				resolveId ( importee, importer ) {
 					return 'main';
 				}
 			}
 		]
 	},
-	error: function ( err ) {
-		assert.equal( err.message, 'nope' );
+	error: {
+		message: 'nope'
 	}
 };

test/function/default-not-reexported/_config.js

@@ -1,8 +1,23 @@
+const path = require( 'path' );
 const assert = require( 'assert' );
 
 module.exports = {
 	description: 'default export is not re-exported with export *',
-	error ( error ) {
-		assert.equal( error.message, `'default' is not exported by foo.js (imported by main.js). For help fixing this error see https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module` );
+	error: {
+		code: 'MISSING_EXPORT',
+		message: `'default' is not exported by foo.js`,
+		pos: 7,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 1,
+			column: 7
+		},
+		frame: `
+			1: import def from './foo.js';
+			          ^
+			2:
+			3: console.log( def );
+		`,
+		url: `https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module`
 	}
 };

test/function/double-default-export/_config.js

@@ -3,7 +3,19 @@ const assert = require( 'assert' );
 
 module.exports = {
 	description: 'throws on double default exports',
-	error: err => {
-		assert.equal( err.message, `Duplicate export 'default' (2:7) in ${path.resolve(__dirname, 'foo.js')}` );
+	error: {
+		code: 'PARSE_ERROR',
+		message: `Duplicate export 'default'`,
+		pos: 25,
+		loc: {
+			file: path.resolve( __dirname, 'foo.js' ),
+			line: 2,
+			column: 7
+		},
+		frame: `
+			1: export default 1;
+			2: export default 2;
+			          ^
+		`
 	}
 };

test/function/double-named-export/_config.js

@@ -3,7 +3,20 @@ const assert = require( 'assert' );
 
 module.exports = {
 	description: 'throws on duplicate named exports',
-	error: err => {
-		assert.equal( err.message, `Duplicate export 'foo' (3:9) in ${path.resolve(__dirname, 'foo.js')}` );
+	error: {
+		code: 'PARSE_ERROR',
+		message: `Duplicate export 'foo'`,
+		pos: 38,
+		loc: {
+			file: path.resolve( __dirname, 'foo.js' ),
+			line: 3,
+			column: 9
+		},
+		frame: `
+			1: var foo = 1;
+			2: export { foo };
+			3: export { foo };
+			            ^
+		`
 	}
 };

test/function/double-named-reexport/_config.js

@@ -3,7 +3,20 @@ const assert = require( 'assert' );
 
 module.exports = {
 	description: 'throws on duplicate named exports',
-	error: err => {
-		assert.equal( err.message, `Duplicate export 'foo' (3:9) in ${path.resolve(__dirname, 'foo.js')}` );
+	error: {
+		code: 'PARSE_ERROR',
+		message: `Duplicate export 'foo'`,
+		pos: 38,
+		loc: {
+			file: path.resolve( __dirname, 'foo.js' ),
+			line: 3,
+			column: 9
+		},
+		frame: `
+			1: var foo = 1;
+			2: export { foo };
+			3: export { foo } from './bar.js';
+			            ^
+		`
 	}
 };

test/function/duplicate-import-fails/_config.js

@@ -3,10 +3,22 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows duplicate imports',
-	error: function ( err ) {
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 36, line: 2, column: 9 });
-		assert.ok( /Duplicated import/.test( err.message ) );
+	error: {
+		code: 'DUPLICATE_IMPORT',
+		message: `Duplicated import 'a'`,
+		pos: 36,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 2,
+			column: 9
+		},
+		frame: `
+			1: import { a } from './foo';
+			2: import { a } from './foo';
+			            ^
+			3:
+			4: assert.equal(a, 1);
+		`
 	}
 };
 

test/function/duplicate-import-specifier-fails/_config.js

@@ -3,10 +3,20 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows duplicate import specifiers',
-	error: function ( err ) {
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 12, line: 1, column: 12 });
-		assert.ok( /Duplicated import/.test( err.message ) );
+	error: {
+		code: 'DUPLICATE_IMPORT',
+		message: `Duplicated import 'a'`,
+		pos: 12,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 1,
+			column: 12
+		},
+		frame: `
+			1: import { a, a } from './foo';
+			               ^
+			2: assert.equal(a, 1);
+		`
 	}
 };
 

test/function/export-not-at-top-level-fails/_config.js

@@ -3,9 +3,20 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows non-top-level exports',
-	error: function ( err ) {
-		assert.equal( path.normalize(err.file), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { line: 2, column: 2 });
-		assert.ok( /may only appear at the top level/.test( err.message ) );
+	error: {
+		code: 'PARSE_ERROR',
+		message: `'import' and 'export' may only appear at the top level`,
+		pos: 19,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 2,
+			column: 2
+		},
+		frame: `
+			1: function foo() {
+			2:   export { foo };
+			     ^
+			3: }
+		`
 	}
 };

test/function/export-type-mismatch-b/_config.js

@@ -5,7 +5,8 @@ module.exports = {
 	bundleOptions: {
 		exports: 'blah'
 	},
-	generateError: function ( err ) {
-		assert.ok( /options\.exports must be 'default', 'named', 'none', 'auto', or left unspecified/.test( err.message ) );
+	generateError: {
+		code: 'INVALID_EXPORT_OPTION',
+		message: `options.exports must be 'default', 'named', 'none', 'auto', or left unspecified (defaults to 'auto')`
 	}
 };

test/function/export-type-mismatch-c/_config.js

@@ -5,7 +5,8 @@ module.exports = {
 	bundleOptions: {
 		exports: 'none'
 	},
-	generateError: function ( err ) {
-		assert.ok( /'none' was specified for options\.exports/.test( err.message ) );
+	generateError: {
+		code: 'INVALID_EXPORT_OPTION',
+		message: `'none' was specified for options.exports, but entry module has following exports: default`
 	}
 };

test/function/export-type-mismatch/_config.js

@@ -5,7 +5,8 @@ module.exports = {
 	bundleOptions: {
 		exports: 'default'
 	},
-	generateError: function ( err ) {
-		assert.ok( /'default' was specified for options\.exports/.test( err.message ) );
+	generateError: {
+		code: 'INVALID_EXPORT_OPTION',
+		message: `'default' was specified for options.exports, but entry module has following exports: foo`
 	}
 };

test/function/import-not-at-top-level-fails/_config.js

@@ -3,9 +3,20 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows non-top-level imports',
-	error: function ( err ) {
-		assert.equal( path.normalize(err.file), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { line: 2, column: 2 });
-		assert.ok( /may only appear at the top level/.test( err.message ) );
+	error: {
+		code: 'PARSE_ERROR',
+		message: `'import' and 'export' may only appear at the top level`,
+		pos: 19,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 2,
+			column: 2
+		},
+		frame: `
+			1: function foo() {
+			2:   import foo from './foo.js';
+			     ^
+			3: }
+		`
 	}
 };

test/function/import-not-at-top-level-fails/main.js

@@ -1,3 +1,3 @@
 function foo() {
-  import foo from './foo';
+  import foo from './foo.js';
 }

test/function/import-of-unexported-fails/_config.js

@@ -1,8 +1,23 @@
+var path = require( 'path' );
 var assert = require( 'assert' );
 
 module.exports = {
 	description: 'marking an imported, but unexported, identifier should throw',
-	error: function ( err ) {
-		assert.equal( err.message, `'default' is not exported by empty.js (imported by main.js). For help fixing this error see https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module` );
+	error: {
+		code: 'MISSING_EXPORT',
+		message: `'default' is not exported by empty.js`,
+		pos: 7,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 1,
+			column: 7
+		},
+		frame: `
+			1: import a from './empty.js';
+			          ^
+			2:
+			3: a();
+		`,
+		url: `https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module`
 	}
 };

test/function/load-returns-string-or-null/_config.js

@@ -4,12 +4,14 @@ module.exports = {
 	description: 'throws error if load returns something wacky',
 	options: {
 		plugins: [{
+			name: 'bad-plugin',
 			load: function () {
 				return 42;
 			}
 		}]
 	},
-	error: function ( err ) {
-		assert.ok( /load hook should return a string, a \{ code, map \} object, or nothing\/null/.test( err.message ) );
+	error: {
+		code: 'BAD_LOADER',
+		message: `Error loading main.js: plugin load hook should return a string, a { code, map } object, or nothing/null`
 	}
 };

test/function/namespace-reassign-import-fails/_config.js

@@ -3,10 +3,21 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows reassignments to namespace exports',
-	error: function ( err ) {
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 31, line: 3, column: 0 });
-		assert.ok( /Illegal reassignment/.test( err.message ) );
+	error: {
+		code: 'ILLEGAL_NAMESPACE_REASSIGNMENT',
+		message: `Illegal reassignment to import 'exp'`,
+		pos: 31,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 3,
+			column: 0
+		},
+		frame: `
+			1: import * as exp from './foo';
+			2:
+			3: exp.foo = 2;
+			   ^
+		`
 	}
 };
 

test/function/namespace-update-import-fails/_config.js

@@ -3,10 +3,21 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows updates to namespace exports',
-	error: function ( err ) {
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 31, line: 3, column: 0 });
-		assert.ok( /Illegal reassignment/.test( err.message ) );
+	error: {
+		code: 'ILLEGAL_NAMESPACE_REASSIGNMENT',
+		message: `Illegal reassignment to import 'exp'`,
+		pos: 31,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 3,
+			column: 0
+		},
+		frame: `
+			1: import * as exp from './foo';
+			2:
+			3: exp['foo']++;
+			   ^
+		`
 	}
 };
 

test/function/no-relative-external/_config.js

@@ -2,7 +2,8 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'missing relative imports are an error, not a warning',
-	error: function ( err ) {
-		assert.ok( /Could not resolve '\.\/missing\.js' from/.test( err.message ) );
+	error: {
+		code: 'UNRESOLVED_IMPORT',
+		message: `Could not resolve './missing.js' from main.js`
 	}
 };

test/function/paths-are-case-sensitive/_config.js

@@ -2,7 +2,8 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'insists on correct casing for imports',
-	error: function ( err ) {
-		assert.ok( /Could not resolve/.test( err.message ) );
+	error: {
+		code: 'UNRESOLVED_IMPORT',
+		message: `Could not resolve './foo.js' from main.js`
 	}
 };

test/function/reassign-import-fails/_config.js

@@ -3,10 +3,21 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows assignments to imported bindings',
-	error: function ( err ) {
-		assert.ok( /Illegal reassignment/.test( err.message ) );
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 113, line: 8, column: 0 });
+	error: {
+		code: 'ILLEGAL_REASSIGNMENT',
+		message: `Illegal reassignment to import 'x'`,
+		pos: 113,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 8,
+			column: 0
+		},
+		frame: `
+			6: });
+			7:
+			8: x = 10;
+			   ^
+		`
 	}
 };
 

test/function/reassign-import-not-at-top-level-fails/_config.js

@@ -3,10 +3,22 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows assignments to imported bindings not at the top level',
-	error: function ( err ) {
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 95, line: 7, column: 2 });
-		assert.ok( /Illegal reassignment/.test( err.message ) );
+	error: {
+		code: 'ILLEGAL_REASSIGNMENT',
+		message: `Illegal reassignment to import 'x'`,
+		pos: 95,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 7,
+			column: 2
+		},
+		frame: `
+			5: }
+			6: export function bar () {
+			7:   x = 1;
+			     ^
+			8: }
+		`
 	}
 };
 

test/function/reexport-missing-error/_config.js

@@ -1,8 +1,21 @@
+var path = require( 'path' );
 var assert = require( 'assert' );
 
 module.exports = {
 	description: 'reexporting a missing identifier should print an error',
-	error: function ( error ) {
-		assert.ok( /^'foo' is not exported/.test( error.message ) );
+	error: {
+		code: 'MISSING_EXPORT',
+		message: `'foo' is not exported by empty.js`,
+		pos: 9,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 1,
+			column: 9
+		},
+		frame: `
+			1: export { foo as bar } from './empty.js';
+			            ^
+		`,
+		url: 'https://github.com/rollup/rollup/wiki/Troubleshooting#name-is-not-exported-by-module'
 	}
 };

test/function/report-transform-error-file/_config.js

@@ -1,9 +1,11 @@
+var path = require( 'path' );
 var assert = require( 'assert' );
 
 module.exports = {
 	description: 'reports which file caused a transform error',
 	options: {
 		plugins: [{
+			name: 'bad-plugin',
 			transform: function ( code, id ) {
 				if ( /foo/.test( id ) ) {
 					throw new Error( 'nope' );
@@ -11,7 +13,10 @@ module.exports = {
 			}
 		}]
 	},
-	error: function ( err ) {
-		assert.ok( ~err.message.indexOf( 'foo.js' ) );
+	error: {
+		code: 'BAD_TRANSFORMER',
+		message: `Error transforming foo.js with 'bad-plugin' plugin: nope`,
+		plugin: 'bad-plugin',
+		id: path.resolve( __dirname, 'foo.js' )
 	}
 };

test/function/reports-syntax-error-locations/_config.js

@@ -1,8 +0,0 @@
-var assert = require( 'assert' );
-
-module.exports = {
-	description: 'reports syntax error filename',
-	error: function ( err ) {
-		assert.ok( /in .+main\.js/.test( err.message ) );
-	}
-};

test/function/reports-syntax-error-locations/main.js

@@ -1 +0,0 @@
-var 42 = answer;

test/function/throws-not-found-module/_config.js

@@ -3,7 +3,8 @@ var path = require( 'path' );
 
 module.exports = {
 	description: 'throws error if module is not found',
-	error: function ( err ) {
-		assert.equal( err.message, 'Could not resolve \'./mod\' from ' + path.resolve( __dirname, 'main.js' ) );
+	error: {
+		code: 'UNRESOLVED_IMPORT',
+		message: `Could not resolve './mod' from main.js`
 	}
 };

test/function/throws-only-first-transform-bundle/_config.js

@@ -7,19 +7,20 @@ module.exports = {
 			{
 				name: 'plugin1',
 				transformBundle: function () {
-					throw Error('Something happend 1');
+					throw Error( 'Something happened 1' );
 				}
 			},
 			{
 				name: 'plugin2',
 				transformBundle: function () {
-					throw Error('Something happend 2');
+					throw Error( 'Something happened 2' );
 				}
 			}
 		]
 	},
-	generateError: function ( err ) {
-		assert.equal( err.plugin, 'plugin1' );
-		assert.equal( err.message, 'Error transforming bundle with \'plugin1\' plugin: Something happend 1' );
+	generateError: {
+		code: 'BAD_BUNDLE_TRANSFORMER',
+		plugin: 'plugin1',
+		message: `Error transforming bundle with 'plugin1' plugin: Something happened 1`
 	}
 };

test/function/throws-only-first-transform/_config.js

@@ -7,23 +7,22 @@ module.exports = {
 		plugins: [
 			{
 				name: 'plugin1',
-				transform: function () {
-					throw Error('Something happend 1');
+				transform () {
+					throw Error( 'Something happened 1' );
 				}
 			},
 			{
 				name: 'plugin2',
-				transform: function () {
-					throw Error('Something happend 2');
+				transform () {
+					throw Error( 'Something happened 2' );
 				}
 			}
 		]
 	},
-	error: function ( err ) {
-		var id = path.resolve( __dirname, 'main.js' );
-		assert.equal( err.rollupTransform, true );
-		assert.equal( err.id, id );
-		assert.equal( err.plugin, 'plugin1' );
-		assert.equal( err.message, 'Error transforming ' + id + ' with \'plugin1\' plugin: Something happend 1' );
+	error: {
+		code: 'BAD_TRANSFORMER',
+		message: `Error transforming main.js with 'plugin1' plugin: Something happened 1`,
+		plugin: 'plugin1',
+		id: path.resolve( __dirname, 'main.js' )
 	}
 };

test/function/update-expression-of-import-fails/_config.js

@@ -3,10 +3,21 @@ var assert = require( 'assert' );
 
 module.exports = {
 	description: 'disallows updates to imported bindings',
-	error: function ( err ) {
-		assert.equal( path.normalize( err.file ), path.resolve( __dirname, 'main.js' ) );
-		assert.deepEqual( err.loc, { character: 28, line: 3, column: 0 });
-		assert.ok( /Illegal reassignment/.test( err.message ) );
+	error: {
+		code: 'ILLEGAL_REASSIGNMENT',
+		message: `Illegal reassignment to import 'a'`,
+		pos: 28,
+		loc: {
+			file: path.resolve( __dirname, 'main.js' ),
+			line: 3,
+			column: 0
+		},
+		frame: `
+			1: import { a } from './foo';
+			2:
+			3: a++;
+			   ^
+		`
 	}
 };
 

test/test.js

@@ -79,6 +79,23 @@ function compareWarnings ( actual, expected ) {
 	);
 }
 
+function compareError ( actual, expected ) {
+	delete actual.stack;
+	actual = Object.assign( {}, actual, {
+		message: actual.message
+	});
+
+	if ( actual.frame ) {
+		actual.frame = actual.frame.replace( /\s+$/gm, '' );
+	}
+
+	if ( expected.frame ) {
+		expected.frame = expected.frame.slice( 1 ).replace( /^\t+/gm, '' ).replace( /\s+$/gm, '' ).trim();
+	}
+
+	assert.deepEqual( actual, expected );
+}
+
 describe( 'rollup', function () {
 	this.timeout( 10000 );
 
@@ -259,7 +276,7 @@ describe( 'rollup', function () {
 							}
 						} catch ( err ) {
 							if ( config.generateError ) {
-								config.generateError( err );
+								compareError( err, config.generateError );
 							} else {
 								unintendedError = err;
 							}
@@ -324,7 +341,7 @@ describe( 'rollup', function () {
 						if ( unintendedError ) throw unintendedError;
 					}, err => {
 						if ( config.error ) {
-							config.error( err );
+							compareError( err, config.error );
 						} else {
 							throw err;
 						}