Merge pull request obsidian-tasks-group#3075 from obsidian-tasks-grou…

…p/fix-filter-by-function-error-messages

fix: Make 'filter by function' show statement in error messages

resources/sample_vaults/Tasks-Demo/Functions/Custom Filters - Demo.md

@@ -43,3 +43,34 @@ filename includes Custom Filters - Demo
 # Infer tag from heading
 filter by function task.heading.includes('#context/home') || task.tags.find( (tag) => tag === '#context/home' ) && true || false
 ```
+
+## Demonstrate Error Handling
+
+### Parsing Errors
+
+This section demonstrate how Tasks handles errors when reading `filter by function` instructions.
+
+#### SyntaxError
+
+```tasks
+filter by function \
+ task.due.formatAsDate(
+```
+
+### Evaluation Errors
+
+This section demonstrate how Tasks handles when evaluating `filter by function` instructions during searches.
+
+#### ReferenceError
+
+```tasks
+filter by function \
+ hello
+```
+
+#### Non-existent task field
+
+```tasks
+filter by function \
+ task.nonExistentField
+```

src/Query/Query.ts

@@ -246,11 +246,15 @@ ${source}`;
  }
 
  private setError(message: string, statement: Statement) {
+ this._error = Query.generateErrorMessage(statement, message);
+ }
+
+ private static generateErrorMessage(statement: Statement, message: string) {
  if (statement.allLinesIdentical()) {
- this._error = `${message}
+ return `${message}
 Problem line: "${statement.rawInstruction}"`;
  } else {
- this._error = `${message}
+ return `${message}
 Problem statement:
 ${statement.explainStatement(' ')}
 `;
@@ -265,10 +269,16 @@ ${statement.explainStatement(' ')}
  this.debug(`Executing query: ${this.formatQueryForLogging()}`);
 
  const searchInfo = new SearchInfo(this.tasksFile, tasks);
+
+ // Custom filter (filter by function) does not report the instruction line in any exceptions,
+ // for performance reasons. So we keep track of it here.
+ let possiblyBrokenStatement: Statement | undefined = undefined;
  try {
  this.filters.forEach((filter) => {
+ possiblyBrokenStatement = filter.statement;
  tasks = tasks.filter((task) => filter.filterFunction(task, searchInfo));
  });
+ possiblyBrokenStatement = undefined;
 
  const { debugSettings } = getSettings();
  const tasksSorted = debugSettings.ignoreSortInstructions ? tasks : Sort.by(this.sorting, tasks, searchInfo);
@@ -283,7 +293,12 @@ ${statement.explainStatement(' ')}
  return new QueryResult(taskGroups, tasksSorted.length);
  } catch (e) {
  const description = 'Search failed';
- return QueryResult.fromError(errorMessageForException(description, e));
+ let message = errorMessageForException(description, e);
+
+ if (possiblyBrokenStatement) {
+ message = Query.generateErrorMessage(possiblyBrokenStatement, message);
+ }
+ return QueryResult.fromError(message);
  }
  }
 

tests/Query/Query.test.ts

@@ -1542,7 +1542,8 @@ describe('Query', () => {
  describe('error handling', () => {
  it('should catch an exception that occurs during searching', () => {
  // Arrange
- const source = 'filter by function wibble';
+ const source = `filter by function \\
+wibble`;
  const query = new Query(source);
  const queryUpper = new Query(source.toUpperCase());
  const task = TaskBuilder.createFullyPopulatedTask();
@@ -1553,10 +1554,26 @@ describe('Query', () => {
 
  // Assert
  expect(queryResult.searchErrorMessage).toEqual(
- 'Error: Search failed.\nThe error message was:\n "ReferenceError: wibble is not defined"',
+ `Error: Search failed.
+The error message was:
+ "ReferenceError: wibble is not defined"
+Problem statement:
+ filter by function \\
+ wibble
+ =>
+ filter by function wibble
+`,
  );
  expect(queryResultUpper.searchErrorMessage).toEqual(
- 'Error: Search failed.\nThe error message was:\n "ReferenceError: WIBBLE is not defined"',
+ `Error: Search failed.
+The error message was:
+ "ReferenceError: WIBBLE is not defined"
+Problem statement:
+ FILTER BY FUNCTION \\
+ WIBBLE
+ =>
+ FILTER BY FUNCTION WIBBLE
+`,
  );
  });
  });