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Fix qt gc segfault - #474
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jenshnielsen merged 2 commits intoOct 6, 2026
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Flowcharts, nodes and their pyqtgraph/Qt objects form reference cycles, so discarded ones are only freed by Python's cyclic garbage collector. When an allocation-triggered collection fires while Qt is constructing graphics items for another flowchart, destroying the old Qt object trees can segfault the process. This crashed the test suite (mid-run on Windows, at interpreter shutdown on Linux CI with Python 3.14) and can also hit the apps, e.g. when inspectr replaces a plot window's flowchart. - Add plottr.enableEventLoopGarbageCollection(), which uses pyqtgraph's GarbageCollector to collect only from the Qt event loop, plus once on aboutToQuit, and enable it in the standalone apps (autoplot, inspectr, monitr, apprunner). Library use is unchanged since this affects the whole interpreter; the README documents how to opt in. - In the test suite, disable automatic collection during each test and collect explicitly afterwards.
dataLoaded is emitted before the queued onThreadComplete() slot updates the flowchart output, so wait for the new data as the first half of the test already does.
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Use garbage collector from pyqtgraph in qt apps. This should resolve crashes due to the std garbage collector not working well with the qt event loop