I thought this was a feature request so I first posted this to the feedback site, but to my surprise it was just deleted without even telling me why. This is the deleted suggestion.

When you install a shader pack that is incompatible with the game version or your device, there will be a compilation error or linkage error in shader programs, but the game hangs up without displaying errors. This makes it awfully hard to debug shader problems. The game should display error messages given by GPU drivers, or at least write them to a log file.

Steps to reproduce:

• Install a broken shader pack attached to MCPE-40059.
• Activate it in the "Global Resource Packs".
• The game hangs up with no error messages.