Output cells not correct with special input

[rchiodo]

This code here:

for i in range(10):
    if i == 8 :
        clear_output(True)
        print('bar 8 {0}'.format(i))
    elif (i % 2 == 0):
        print('bar even')
        display('bar-d {0}'.format(i))
    else: 
        display('bar-d {0}'.format(i))
        print('bar odd')

Produces this for us:

bar even
'bar-d 9'
bar odd
bar even
bar odd
bar even
bar odd
bar even
bar 8 8
bar odd

And this for jupyter:

bar 8 8
'bar-d 9'
bar odd

[rchiodo]

This is related to trying to match the output concatenation strategy that jupyter takes.

[rchiodo]

This might fix the problem:

Change:

    private handleStreamMesssage(msg: KernelMessage.IStreamMsg, clearState: Map<string, boolean>, cell: ICell, trimFunc: (str: string) => string) {
        // Might already have a stream message. If so, just add on to it.
        const data: nbformat.ICodeCell = cell.data as nbformat.ICodeCell;
        const existing = data.outputs.length > 0 && data.outputs[data.outputs.length - 1].output_type === 'stream' ? data.outputs[data.outputs.length - 1] : undefined;
        if (existing) {
            // If clear pending, then don't add.
            if (clearState.get('stream')) {
                clearState.delete('stream'); <-- Eliminate this line so that the delete happens after this point
                existing.text = msg.content.text;
            } else {
                // tslint:disable-next-line:restrict-plus-operands
                existing.text = existing.text + msg.content.text;
                existing.text = trimFunc(formatStreamText(concatMultilineStringOutput(existing.text)));
            }
        } else {
            // Create a new stream entry
            const output: nbformat.IStream = {
                output_type: 'stream',
                name: msg.content.name,
                text: trimFunc(formatStreamText(concatMultilineStringOutput(msg.content.text)))
            };
            this.addToCellData(cell, output, clearState);
        }
    }

[rchiodo]

Only fix this if the suggestion works.

[IanMatthewHuff]

Validated.