[digikam] [Bug 524393] New: Crash when dragging image in library to re-position it

https://bugs.kde.org/show_bug.cgi?id=524393

            Bug ID: 524393
           Summary: Crash when dragging image in library to re-position it
    Classification: Applications
           Product: digikam
      Version First 9.2.0
       Reported In:
          Platform: Other
                OS: macOS
            Status: REPORTED
          Severity: crash
          Priority: NOR
         Component: general
          Assignee: [email protected]
          Reporter: [email protected]
  Target Milestone: ---

Created attachment 195233
  --> https://bugs.kde.org/attachment.cgi?id=195233&action=edit
Crash dump

DESCRIPTION
Dragging image in library to reorder sometimes results in crash

Summary -
Root cause: a crash inside Qt's macOS drag-image code path, triggered by an
invalid/corrupt colorspace object passed to CGImageCreate.

The crashing thread (thread 0, main thread) was in the middle of starting a
drag-and-drop operation:

Digikam::DragDropViewImplementation::startDrag
→ QDrag::exec / QDragManager::drag
→ -[NSWindow(NSDrag) dragImage:...]
→ QImage::toCGImage()
→ CGImageCreate → verify_image_parameters → valid_image_colorspace →
CGColorSpaceGetType → CFGetTypeID → __CF_IS_OBJC

Started dragging an item — A thumbnail in the icon/item view (DCategorizedView
/ ItemViewCategorized::mouseMoveEvent) — and Qt tried to build a CGImage for
the drag ghost image via QImage::toCGImage(). That function hands the image's
CGColorSpace to CGImageCreate. Core Graphics then tries to type-check that
colorspace object (CGColorSpaceGetType → CFGetTypeID), and the ARM64e
pointer-authentication check on it fails (esr: pointer authentication trap DA,
far: 0x0). That means the colorspace pointer being passed in isn't a valid,
live Objective-C/CoreFoundation object — it's garbage, null-ish, or already
freed. In short: the QImage being dragged has a corrupted/invalid color space,
and CGImageCreate traps trying to validate it.

Seems it's a bug in how digiKam (via Qt6) constructs the QImage used for the
drag thumbnail, most likely triggered by a specific image's embedded color
profile (e.g. a CMYK, unusual ICC, or 16-bit image) producing a QImage whose
internal colorSpace() is malformed by the time it's converted for the native
drag image.

OBSERVED RESULT
Crash

EXPECTED RESULT
Thumbnail moved

SOFTWARE/OS VERSIONS
MacOS 26.6


ADDITIONAL INFORMATION
Mac OS Crash dump added as attachment

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