Annotations: duplicate annotations in CSS mode

[BenSouchet]

Describe the bug

In CSS mode if we enter this:

h2 {
    

The newlines are mandatory to ensure the bug to occurs.

We get 2x the exact same "error" annotation (same text, row, col, rule, ...).

I currently use the 1.5.0 ace-min version available in the build repo.

Expected Behavior

Only one annotation. Not twice the same one.

Current Behavior

Currently we get twice the exact same annotation:

{row: 2, column: 0, text: "Unexpected token 'null' at line 3, col 1.", type: 'error', rule: 'Parsing Errors'}
{row: 2, column: 0, text: "Unexpected token 'null' at line 3, col 1.", type: 'error', rule: 'Parsing Errors'}

Reproduction Steps

Initialize an Ace editor with CSS mode, then enter these lines:

h2 {
    

The newlines are required.

Now if you console log the annotations of the current Editor session you will get:

{row: 2, column: 0, text: "Unexpected token 'null' at line 3, col 1.", type: 'error', rule: 'Parsing Errors'}
{row: 2, column: 0, text: "Unexpected token 'null' at line 3, col 1.", type: 'error', rule: 'Parsing Errors'}

Twice the same with the exact same line and column.

Possible Solution

No response

Additional Information/Context

No response

Ace Version

1.5.0

[BenSouchet]

Additional info: I have tested on version 1.5.3 just in case, and the issue is the same.

[BenSouchet]

@andrewnester I tried to investigate a bit 🙂
After a bit of time and a lot of breakpoints I understood that two annotations are registered because when verifying the CSS code in the worker-css.js:

• There is a first SyntaxError catch in _readDeclarations() (called by _ruleset(), itself called by _stylesheet()).
• Still in _readDeclarations() there is these lines:

else if (tt !== Tokens.RBRACE) {
    throw ex;
}

• So the exception is forwarded and catch again by the caller _stylesheet(), this will generate the second msg.

When the exception is caught a reporter.error( is called to add an error, this is why there is two times the exact same annotation.

The questions are:

• Why in _readDeclarations() the exception is consumed and throw to be consumed again ?
• Why the token value is null? Since the true error is missing RBRACE.

[BenSouchet]

I created a Pull Request ( #4816 ) to fix this wrong double error and fire the correct one. I close the issue 🙂