Error: length < 0 in createTextSpan during getApplicableRefactors

[aozgaa]

tsserver version: 2.6.1
Error: length < 0
at createTextSpan (tsserver.js:8817:19)
at Object.createTextSpanFromBounds (tsserver.js:8823:16)
at getErrorSpanForNode (tsserver.js:6264:19)
at createDiagnosticForNodeInSourceFile (tsserver.js:6195:20)
at Object.createDiagnosticForNode (tsserver.js:6191:16)
at checkNode (tsserver.js:77699:36)
at getRangeToExtract (tsserver.js:77655:54)
at Object.getAvailableActions (tsserver.js:77509:38)
at tsserver.js:75017:128
at Object.flatMapIter (tsserver.js:1570:23)
at Object.getApplicableRefactors (tsserver.js:75016:23)
at Object.getApplicableRefactors (tsserver.js:80232:32)
at IOSession.Session.getApplicableRefactors (tsserver.js:86474:53)
at Session.handlers.ts.createMapFromTemplate._a.(anonymous function) (tsserver.js:85436:61)
at tsserver.js:86669:88
at IOSession.Session.executeWithRequestId (tsserver.js:86660:28)
at IOSession.Session.executeCommand (tsserver.js:86669:33)
at IOSession.Session.onMessage (tsserver.js:86689:35)
at Interface. (tsserver.js:87881:27)
at emitOne (events.js:96:13)
at Interface.emit (events.js:191:7)
at Interface._onLine (readline.js:241:10)
at Interface._normalWrite (readline.js:384:12)
at Socket.ondata (readline.js:101:10)
at emitOne (events.js:96:13)
at Socket.emit (events.js:191:7)
at readableAddChunk (_stream_readable.js:178:18)
at Socket.Readable.push (_stream_readable.js:136:10)
at Pipe.onread (net.js:560:20)

[mhegazy]

The Source: Telemetry have limited information. we only have the call stack from the crash report. We need to either mitigate the crash, or add additional asserts to get more information in future crash reports.

[amcasey]

@aozgaa Can I assume this is from 2.6.1, like the others?

[amcasey]

        var pos = nodeIsMissing(errorNode)
            ? errorNode.pos
            : ts.skipTrivia(sourceFile.text, errorNode.pos);
        return ts.createTextSpanFromBounds(pos, errorNode.end);

It seems plausible that skipTrivia might advance past errorNode.end.

[amcasey]

This is the diagnostic we're trying to create:

            if (!isStatement(nodeToCheck) && !(isExpressionNode(nodeToCheck) && isExtractableExpression(nodeToCheck))) {
                return [createDiagnosticForNode(nodeToCheck, Messages.statementOrExpressionExpected)];
            }

[amcasey]

nodeIsMissing will only return true if errorNode is undefined (not the case, since we're accessing properties) or if errorNode.pos === errorNode.end. Therefore, if we take that branch, length is guaranteed to be 0 (i.e. no assert).

[aozgaa]

Yes. All reported issues so far are from 2.6.1. I've updated the description to reflect this.

[amcasey]

Waiting for asserts to be hit (not yet shipped).

[amcasey]

We had a telemetry hit in VS Code 1.28.1 with TS 3.1.1:

Error processing request. Debug Failure. False expression: This failure could trigger https://github.com/Microsoft/TypeScript/issues/20809
Error: Debug Failure. False expression: This failure could trigger https://github.com/Microsoft/TypeScript/issues/20809
    at getErrorSpanForNode (tsserver.js:8839:22)
    at createDiagnosticForNodeInSourceFile (tsserver.js:8752:20)
    at Object.createDiagnosticForNode (tsserver.js:8743:16)
    at checkNode (tsserver.js:111533:36)
    at getRangeToExtract (tsserver.js:111452:53)
    at Object.getAvailableActions (tsserver.js:111260:38)
    at tsserver.js:106434:128
    at getIterator (tsserver.js:535:23)
    at Object.next (tsserver.js:530:35)
    at Object.arrayFrom (tsserver.js:1135:32)
    at Object.getApplicableRefactors (tsserver.js:106433:23)
    at Object.getApplicableRefactors (tsserver.js:115353:32)
    at IOSession.Session.getApplicableRefactors (tsserver.js:122853:53)
    at Session.handlers.ts.createMapFromTemplate._a.(anonymous function) (tsserver.js:121787:61)
    at tsserver.js:123061:88
    at IOSession.Session.executeWithRequestId (tsserver.js:123052:28)
    at IOSession.Session.executeCommand (tsserver.js:123061:33)
    at IOSession.Session.onMessage (tsserver.js:123081:35)
    at Interface.<anonymous> (tsserver.js:124344:27)
    at emitOne (events.js:116:13)
    at Interface.emit (events.js:211:7)
    at Interface._onLine (readline.js:282:10)
    at Interface._normalWrite (readline.js:424:12)
    at Socket.ondata (readline.js:141:10)
    at emitOne (events.js:116:13)
    at Socket.emit (events.js:211:7)
    at addChunk (_stream_readable.js:263:12)
    at readableAddChunk (_stream_readable.js:250:11)
    at Socket.Readable.push (_stream_readable.js:208:10)
    at Pipe.onread (net.js:594:20)

[RyanCavanaugh]

Closing in the absence of a concrete repro