Extend IPreprocessBuildWithReport, IPostprocessBuildWithReport to handle a failed build case
Quite often Unity developers have to cut into Unity build pipeline by implementing both IPreprocessBuildWithReport and IPostprocessBuildWithReport. For instance, for some given platforms it may be necessary to copy some assets into 'StreamingAssets' directory before the build and clean-up those files after the build. Or apply some settings in 'PlayerSettings' prior to the build and restore original ones after that.
Unfortunately, IPreprocessBuildWithReport and IPostprocessBuildWithReport do not provide any callback to handle the situation when the build failed. This results in uncleaned / unrestored state of the project when it's incorrectly filled with temporary setting and unnecessary / undesired files which in turn litters the version control system. Meh.
I tried to fix this situation by implementing an abstract class BaseProcessBuildWithReportSafe which implements both IPreprocessBuildWithReport and IPostprocessBuildWithReport and provides an extra abstract method OnBuildFailed which is called (as it's seen from its name) in case the build failed.
Despite I tested this solution in a real project, I'm still not sure that it can handle every case of the failed build. The fact is that Unity does not provide any API to catch exceptions globaly. That's why I had to use Application.logMessageReceived to intercept the logs and by searching for some footprints to determine that the build actually failed.
It means that this routine may be extended or changed in future to detect build fails more reliably.
Just inherit BaseProcessBuildWithReportSafe class and override OnPostprocessBuild, OnPreprocessBuild, OnBuildFailed methods.
OnBuildFailed takes a BuildReport as a parameter. Depending on when the build actually failed (during OnPostprocessBuild stage or after that) it may receive a report passed either to OnPostprocessBuild or to OnPreprocessBuild (check source code for details).