qt: Fix random segfault when closing "Choose data directory" dialog #8540

1. 
   laanwj commented at 3:02 PM on August 18, 2016: member

   The pickDataDirectory() function was calling exit(0) to quit the application when the user closes the dialog without choosing a data directory.

   This is a bad idea because a background thread is created (to check free space on the drive of the currently selected datadir). The thread is not stopped and unwound properly, resulting in a potential race condition somewhere deep in Qt (while running exit-triggered destructors).

   So replace the exit() by a boolean return value, and let the stack unwind normally.

2. qt: Fix random segfault when closing "Choose data directory" dialog

   The `pickDataDirectory()` function was calling `exit(0)` to quit
   the application when the user closes the dialog without choosing
   a data directory.
   
   This is a bad idea because a background thread is created (to
   check free space on the drive of the currently selected datadir).
   The thread is not stopped and unwound properly, resulting in a potential
   race condition somewhere deep in Qt.
   
   So replace the `exit()` by a boolean return value, and let the
   stack unwind normally.

   b4a9aa511c
3. laanwj added the label Bug on Aug 18, 2016
4. laanwj added the label GUI on Aug 18, 2016
5. 
   MarcoFalke commented at 4:01 PM on August 18, 2016: member

   Concept ACK b4a9aa511c95a1bd0da8ae363b3b9c0b3b7afe4e. Is this something for 13.1?

6. laanwj added this to the milestone 0.13.1 on Aug 18, 2016
7. laanwj added the label Needs backport on Aug 18, 2016
8. 
   laanwj commented at 4:03 PM on August 18, 2016: member

   Concept ACK b4a9aa5. Is this something for 13.1?

   yes, probably

9. laanwj merged this on Aug 19, 2016
10. laanwj closed this on Aug 19, 2016

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11. laanwj referenced this in commit 36404aeec8 on Aug 19, 2016
12. sipa cross-referenced this on Sep 7, 2016 from issue [0.13] Various backports by sipa
13. MarcoFalke removed the label Needs backport on Sep 9, 2016
14. kyuupichan cross-referenced this on Mar 5, 2017 from issue [Backport] Fix Qt Segfault by kyuupichan
15. kyuupichan cross-referenced this on Mar 5, 2017 from issue [backport] bitcoin-cli: Use symbolic constants by kyuupichan
16. sickpig referenced this in commit decc308a8f on Mar 31, 2017
17. sickpig referenced this in commit db3cc0b388 on Apr 5, 2017
18. codablock referenced this in commit c4a35b1dd8 on Sep 19, 2017
19. codablock referenced this in commit ea8beb88be on Dec 29, 2017
20. codablock referenced this in commit 80573f2bf4 on Jan 8, 2018
21. andvgal referenced this in commit ab958c5dd9 on Jan 6, 2019
22. bitcoin locked this on Sep 8, 2021

Milestone
0.13.1