Addon Manager: Refactor to use QNetworkAccessManager for (almost) everything

[chennes]

Migrate all network access to use a single global instance of QNetworkAccessManager (the recommended approach from Qt). This provides the following benefits:

• Better interruption of long-running network accesses
• Support for authenticated proxies
• Automatic proxy credential caching
• Automatic data caching
• Better support for modern SSL connections
• Non-blocking network access

This is purely refactoring: except for the added support for authenticated proxies, and better error messaging for a missing QtNetwork dependency, there are no user-visible changes. To test, simply ensure that you can continue to use the Addon Manager as usual.

If you are behind an authenticated proxy and can assist with debugging that part of the code, please post here or contact me on the FreeCAD forum.

[freecadci]

for feature branch PR_5412. Pipeline 454040883 was triggered at d762024. All CI branches and pipelines.

[freecadci]

for feature branch PR_5412. Pipeline 455232665 was triggered at db31c05. All CI branches and pipelines.

[marioalexis84]

@chennes with this commit I get random crashes when the program is closed.
I'm able to randomly reproduce the crash by making multiple attemps to open-close the program.
Example:
On 10 attemps to open and close the program, I get approx. 5 or 6 crashes.
I think this is related to this commit because I tried identical sequences with the previous commit and I can't reproduce the crashes.

Here the crash message:

Program received signal SIGSEGV, Segmentation fault.
#0  /usr/lib/libc.so.6(+0x3cda0) [0x7f35bcf8eda0]
#1  /usr/lib/libpython3.10.so.1.0(+0x15c56b) [0x7f35bf4f356b]
#2  /usr/lib/python3.10/site-packages/PySide2/QtCore.cpython-310-x86_64-linux-gnu.so(+0xab4e7) [0x7f358eea74e7]
#3  /usr/lib/libQt5Core.so.5(+0xe488c) [0x7f35bd54388c]
#4  /usr/lib/libpthread.so.0(+0x9259) [0x7f35be946259]
#5  /usr/lib/libc.so.6(clone+0x43) [0x7f35bd0505e3]
Program received signal SIGSEGV, Segmentation fault.
#0  /usr/lib/libc.so.6(+0x3cda0) [0x7f35bcf8eda0]
#1  0x7f35bd372986 in Shiboken::BindingManager::BindingManagerPrivate::releaseWrapper(void*, SbkObject*) from /usr/lib/libshiboken2.cpython-310-x86_64-linux-gnu.so.5.15+0x16
#2  0x7f35bd375f2a in Shiboken::BindingManager::releaseWrapper(SbkObject*) from /usr/lib/libshiboken2.cpython-310-x86_64-linux-gnu.so.5.15+0x8a
#3  /usr/lib/libshiboken2.cpython-310-x86_64-linux-gnu.so.5.15(+0x28d0b) [0x7f35bd379d0b]
#4  /usr/lib/libshiboken2.cpython-310-x86_64-linux-gnu.so.5.15(+0x18544) [0x7f35bd369544]
#5  /usr/lib/libpython3.10.so.1.0(+0x1f642b) [0x7f35bf58d42b]
#6  /usr/lib/libpython3.10.so.1.0(+0x1b3960) [0x7f35bf54a960]
#7  /usr/lib/libpython3.10.so.1.0(+0x12c25a) [0x7f35bf4c325a]
#8  /usr/lib/libpython3.10.so.1.0(+0x21fc2c) [0x7f35bf5b6c2c]
#9  /usr/lib/libpython3.10.so.1.0(+0x21f123) [0x7f35bf5b6123]
#10  /usr/lib/libpython3.10.so.1.0(Py_FinalizeEx+0x13d) [0x7f35bf5b378d]
#11  0x7f35bfe2dca5 in Base::InterpreterSingleton::finalize() /lib/libFreeCADBase.so+0x21

[luzpaz]

@marioalexis84 please crash output in code tags since the # by itself will reference other PRs

[chennes]

Thanks for the report, I'll look into it.

[marioalexis84]

Seems to be solved by f045a0b