Fix NPEs in MenuItem#calculateRenderSize() and MenuItem#getMonitorZoom() #2357
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ShahzaibIbrahim
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The change looks fine. I just wonder if there is a reason to not fix getMonitorZoom() in the same way in this PR as well?
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No, I just missed it. |
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Previously, calculateRenderSize() and getMonitorZoom() of MenuItem used getMenu() to get some context providing the relevant shell instead of getParent(). Since that menu may be null when the MenuItem has no submenu (e.g., PUSH, CHECK styles), an NPE might have been thrown. This change replaces getMenu().getShell() with getParent().getShell(), ensuring a valid shell is always used regardless of item type. Fixes eclipse-platform#2247
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Thank you! The changes look simple and reasonable.
I have tested them with multiple configurations (including applications with DPI awareness "System" and "PerMonitorV2" and particularly including dark theme) in which the affected code is executed and relevant. I found no changes in behavior, except that the bug reported in #2247 does not occur anymore.
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Problem Description
In
MenuItem#calculateRenderSize, a GC (graphics context) is created usingthis.getMenu().getShell(). However, this assumes that the menu returned bygetMenu()is non-null, which is only valid for MenuItems with styleSWT.CASCADEthat have an explicitly assigned submenu.For MenuItems with styles like
SWT.PUSH,SWT.CHECK, orSWT.RADIO, the result ofgetMenu()is null, as these items do not have submenus. Attempting to callgetShell()on a null Menu leads to aNullPointerExceptionduring size computation.To address this, we replace:
GC gc = new GC(this.getMenu().getShell());with:
GC gc = new GC(this.getParent().getShell());This ensures that the GC is always created using the Shell associated with the parent Menu, which is guaranteed to exist, regardless of the MenuItem style.
How to Reproduce
In order to reproduce, run the runtime workspace with following plug-in added to your configuration:
org.eclipse.ui.examples.contributionsand add these two menuItem in menucontributionPreviously, you would have got this error:
Expected result
No error should appear in console.
fixes: #2247