Yes, this is a problem with ccache. Whenever "File truncated" issue is detected in the log file on Travis:
sgrogan wrote: ↑
Wed Sep 25, 2019 1:05 pm
I have permissions to delete the cache if desired. Let me know.
This should resolve it. A bit of background, on why such issue can occur from time to time:
Bionic (GCC) toolchain is slightly slower, compared to the Trusty one. 2 h 30 min time limit, currently set, therefore isn't enough anymore, to compile FreeCAD. A workaround is currently being used, that forcefully stops the build procedure at around 2 h 15 min. That gives Travis enough time to still upload created ccache. Restarting the build, or one of the next scheduled builds, will be able to use the existing ccache, and to complete faster. Now one of the possible issues, forcibly terminnating the build, can be the mentioned issue. On a local build such file can simply get deleted, on Travis, the easiest solution is to clear ccache.
P.S. Ideally somebody will ask Travis people if they can extend the time limit to 3 h. If granted, the workaround can get removed and we get to compile FreeCAD again without such potential issues. That is until FreeCAD grows again, and exceeds 3 h limit.