Can QML caching in Qt 5.8 be disabled for a particular project?

Question

Qt 5.8 was supposed to come with the optional use ahead of time qtquick compiler, instead it arrived with a sort-of-a-jit-compiler, a feature that's enabled by default and caches compiled QML files on disk in order to improve startup performance and reduce memory usage.

The feature however arrives with serious bugs which greatly diminish, or in my case even completely negate its benefits, as I didn't have a problem with startup times to begin with, and testing didn't reveal any memory usage improvements whatsoever.

So what I would like to do is opt out of that feature in my project, but I don't seem to find how to do that. Going back to Qt 5.7.1 is not an option since my project relies on other new features, introduced with 5.8.

Answer 1

Add QML_DISABLE_DISK_CACHE (set to 1) to your environment variables. You should be able to do it inside your application via qputenv -- put it somewhere in main before loading QML content.

Answer 2

Credit to peppe for informing us of the environment variable, but qputenv()only takes a QByteArray as the value parameter, so 1 won't work.

The two options that work:

qputenv("QML_DISABLE_DISK_CACHE", "1"); // or
qputenv("QML_DISABLE_DISK_CACHE", "true");

This successful disables the cache and prevents the associated bugs from manifesting.