Implement error handling in the refactored builder

moor/example/example.g.dart

@@ -829,15 +829,6 @@ class $IngredientInRecipesTable extends IngredientInRecipes
   }
 }
 
-class TotalWeightResult {
-  final String title;
-  final int totalWeight;
-  TotalWeightResult({
-    this.title,
-    this.totalWeight,
-  });
-}
-
 abstract class _$Database extends GeneratedDatabase {
   _$Database(QueryExecutor e) : super(const SqlTypeSystem.withDefaults(), e);
   $CategoriesTable _categories;
@@ -879,3 +870,12 @@ abstract class _$Database extends GeneratedDatabase {
   List<TableInfo> get allTables =>
       [categories, recipes, ingredients, ingredientInRecipes];
 }
+
+class TotalWeightResult {
+  final String title;
+  final int totalWeight;
+  TotalWeightResult({
+    this.title,
+    this.totalWeight,
+  });
+}

moor/test/data/tables/todos.g.dart

@@ -1282,32 +1282,6 @@ class $PureDefaultsTable extends PureDefaults
   }
 }
 
-class AllTodosWithCategoryResult {
-  final int id;
-  final String title;
-  final String content;
-  final DateTime targetDate;
-  final int category;
-  final int catId;
-  final String catDesc;
-  AllTodosWithCategoryResult({
-    this.id,
-    this.title,
-    this.content,
-    this.targetDate,
-    this.category,
-    this.catId,
-    this.catDesc,
-  });
-}
-
-class FindCustomResult {
-  final MyCustomObject custom;
-  FindCustomResult({
-    this.custom,
-  });
-}
-
 abstract class _$TodoDb extends GeneratedDatabase {
   _$TodoDb(QueryExecutor e) : super(const SqlTypeSystem.withDefaults(), e);
   $TodosTableTable _todosTable;
@@ -1480,6 +1454,32 @@ abstract class _$TodoDb extends GeneratedDatabase {
       ];
 }
 
+class AllTodosWithCategoryResult {
+  final int id;
+  final String title;
+  final String content;
+  final DateTime targetDate;
+  final int category;
+  final int catId;
+  final String catDesc;
+  AllTodosWithCategoryResult({
+    this.id,
+    this.title,
+    this.content,
+    this.targetDate,
+    this.category,
+    this.catId,
+    this.catDesc,
+  });
+}
+
+class FindCustomResult {
+  final MyCustomObject custom;
+  FindCustomResult({
+    this.custom,
+  });
+}
+
 // **************************************************************************
 // DaoGenerator
 // **************************************************************************

moor_generator/lib/src/analyzer/errors.dart

@@ -1,14 +1,30 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:collection/collection.dart';
 import 'package:meta/meta.dart';
+import 'package:source_gen/source_gen.dart';
 import 'package:source_span/source_span.dart';
 
+typedef LogFunction = void Function(dynamic message,
+    [Object error, StackTrace stackTrace]);
+
 /// Base class for errors that can be presented to an user.
 class MoorError {
   final Severity severity;
   final String message;
 
   MoorError({@required this.severity, this.message});
+
+  bool get isError =>
+      severity == Severity.criticalError || severity == Severity.error;
+
+  @override
+  String toString() {
+    return 'Error: $message';
+  }
+
+  void writeDescription(LogFunction log) {
+    log(message);
+  }
 }
 
 class ErrorInDartCode extends MoorError {
@@ -19,6 +35,16 @@ class ErrorInDartCode extends MoorError {
       this.affectedElement,
       Severity severity = Severity.warning})
       : super(severity: severity, message: message);
+
+  @override
+  void writeDescription(LogFunction log) {
+    if (affectedElement != null) {
+      final span = spanForElement(affectedElement);
+      log(span.message(message));
+    } else {
+      log(message);
+    }
+  }
 }
 
 class ErrorInMoorFile extends MoorError {
@@ -29,6 +55,11 @@ class ErrorInMoorFile extends MoorError {
       String message,
       Severity severity = Severity.warning})
       : super(message: message, severity: severity);
+
+  @override
+  void writeDescription(LogFunction log) {
+    log(span.message(message));
+  }
 }
 
 class ErrorSink {

moor_generator/lib/src/analyzer/session.dart

@@ -48,20 +48,18 @@ abstract class FileTask<R extends ParsedFile> {
   FutureOr<R> compute();
 
   void printErrors() {
-    /*
-    * if (session.errors.errors.isNotEmpty) {
-      print('Warning: There were some errors while running '
-          'moor_generator on ${buildStep.inputId.path}:');
+    final foundErrors = errors.errors;
+    if (foundErrors.isNotEmpty) {
+      final log = backendTask.log;
 
-      for (var error in session.errors.errors) {
-        print(error.message);
+      log.warning('There were some errors while running '
+          'moor_generator on ${backendTask.entrypoint}:');
 
-        if (error.affectedElement != null) {
-          final span = spanForElement(error.affectedElement);
-          print('${span.start.toolString}\n${span.highlight()}');
-        }
+      for (var error in foundErrors) {
+        final printer = error.isError ? log.warning : log.info;
+        error.writeDescription(printer);
       }
-    } */
+    }
   }
 }
 
@@ -116,7 +114,10 @@ class DartTask extends FileTask<ParsedDartFile> {
       } else {
         return parser.parseTable(type.element as ClassElement);
       }
-    })).then((list) => List.from(list)); // make growable
+    })).then((list) {
+      // only keep tables that were resolved successfully
+      return List.from(list.where((t) => t != null));
+    });
   }
 
   /// Reads all tables declared in sql by a `.moor` file in [paths].

moor_generator/lib/src/analyzer/sql_queries/sql_parser.dart

@@ -38,21 +38,21 @@ class SqlParser {
       } catch (e, s) {
         task.reportError(MoorError(
             severity: Severity.criticalError,
-            message: 'Error while trying to parse $sql: $e, $s'));
+            message: 'Error while trying to parse $key: $e, $s'));
         return;
       }
 
       for (var error in context.errors) {
         task.reportError(MoorError(
           severity: Severity.warning,
-          message: 'The sql query $sql is invalid: $error',
+          message: 'The sql query $key is invalid: $error',
         ));
       }
 
       try {
         foundQueries.add(QueryHandler(name, context, _mapper).handle());
       } catch (e, s) {
-        log.warning('Error while generating APIs for ${context.sql}', e, s);
+        log.warning('Error while generating APIs for $key', e, s);
       }
     });
   }

moor_generator/lib/src/writer/queries/query_writer.dart

@@ -311,15 +311,15 @@ class QueryWriter {
       // write everything that comes before this var into the_buffer
       final currentIndex = sqlVar.firstPosition;
       final queryPart = query.sql.substring(lastIndex, currentIndex);
-      _buffer.write(escapeForDart(queryPart));
+      buffer.write(escapeForDart(queryPart));
       lastIndex = sqlVar.lastPosition;
 
       // write the ($expandedVar) par
-      _buffer.write('(\$${_expandedName(moorVar)})');
+      buffer.write('(\$${_expandedName(moorVar)})');
     }
 
     // write the final part after the last variable, plus the ending '
-    _buffer..write(escapeForDart(query.sql.substring(lastIndex)))..write("'");
+    buffer..write(escapeForDart(query.sql.substring(lastIndex)))..write("'");
 
     return buffer.toString();
   }

moor_generator/lib/src/writer/tables/table_writer.dart

@@ -12,9 +12,7 @@ class TableWriter {
 
   StringBuffer _buffer;
 
-  TableWriter(this.table, this.scope) {
-    _buffer = scope.leaf();
-  }
+  TableWriter(this.table, this.scope);
 
   void writeInto() {
     writeDataClass();
@@ -27,6 +25,8 @@ class TableWriter {
   }
 
   void writeTableInfoClass() {
+    _buffer = scope.leaf();
+
     final dataClass = table.dartTypeName;
     final tableDslName = table.fromClass?.name ?? 'Table';
 

moor_generator/lib/src/writer/writer.dart

@@ -10,10 +10,12 @@ import 'package:moor_generator/src/backends/build/moor_builder.dart';
 /// [StringBuffer] to the generators that will get ugly to manage, but when
 /// passing a [Scope] we will always be able to write code in a parent scope.
 class Writer {
-  final Scope _root = Scope(parent: null);
+  /* late final */ Scope _root;
   final MoorOptions options;
 
-  Writer(this.options);
+  Writer(this.options) {
+    _root = Scope(parent: null, writer: this);
+  }
 
   String writeGenerated() => _leafNodes(_root).join();