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Add a protection against undefined fPainter #22832

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Add a protection against undefined fPainter #22832

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1 change: 1 addition & 0 deletions graf2d/gpad/src/TCanvas.cxx
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Expand Up @@ -620,6 +620,7 @@ void TCanvas::Build()
} else {
//normal mode with a screen window
// Set default physical canvas attributes
if (!fPainter) return;

@silverweed silverweed Jul 24, 2026

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Isn't this early return dangerous? It will leave a bunch of stuff uninitialized that may be assumed to exist later (such as fContextMenu, fPrimitives, ...)

It will also not add this canvas to the global list, which leaves it in a weird half-constructed state..

@linev linev Jul 24, 2026

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Here is better solution #22911

@couet couet Jul 24, 2026

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My fix was mainly a temporary one to show where the problem was. It helped the user who reported the problem.

fPainter->SelectDrawable(fCanvasID);
fPainter->SetAttFill({1, 1001}); //Set color index for fill area
fPainter->SetAttLine({1, 1, 1}); //Set color index for lines
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