RescuedExceptionInterceptor: Handle empty configuration

[MrSerth]

Previously, it could happen that Sentry.configuration was nil. In this case, calling rails would produce a NoMethodError. We fix this issue by using safe navigation.

Furthermore, this commit ensures we use a reasonable default in case the configuration couldn't be loaded. Since the config report_rescued_exceptions defaults to true, we assume this value here, too.

Fixes #2386

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 98.15%. Comparing base (9bba2ef) to head (226ff07).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
.../lib/sentry/rails/rescued_exception_interceptor.rb	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2428      +/-   ##
==========================================
- Coverage   98.18%   98.15%   -0.03%     
==========================================
  Files         126      126              
  Lines        4726     4728       +2     
==========================================
+ Hits         4640     4641       +1     
- Misses         86       87       +1     

Components	Coverage Δ
sentry-ruby	98.51% <ø> (ø)
sentry-rails	97.05% <66.66%> (-0.15%)	⬇️
sentry-sidekiq	97.47% <ø> (ø)
sentry-resque	92.85% <ø> (ø)
sentry-delayed_job	95.65% <ø> (ø)
sentry-opentelemetry	99.31% <ø> (ø)

Files with missing lines	Coverage Δ
.../lib/sentry/rails/rescued_exception_interceptor.rb	93.75% <66.66%> (-6.25%)	⬇️

[solnic]

Sorry but I'm having second thoughts about this, it's the same as I outlined here #2396 (comment)

[MrSerth]

I've had a quick look at the two test failures. The second one is caused by Docker Pull Limits, the first one failed when setting up Ruby 2.5. Both don't look related, I'd say. How can we proceed here?

[solnic]

I've had a quick look at the two test failures. The second one is caused by Docker Pull Limits, the first one failed when setting up Ruby 2.5. Both don't look related, I'd say. How can we proceed here?

I handled those failures. We should be good to merge this.