fix: add empty glob error when no files match

[gantony]

Implements #1250.

What

This PR adds an "empty glob" error when trying to include files using a glob pattern, but the pattern does not match any file.

Why

If a user specifies a config file with Include rules./*.conf, the intent is that a number of files will be parsed (at least 1 😅).
If for some reason the glob pattern does not match any file, we should return an error so that the user realizes there is a problem with the configuration.
The user can then fix the glob pattern (or remove it if not needed), instead of assuming that the expected configuration files have been loaded.

Checklist

• My code includes positive and negative tests.
• I have an appropriate description with correct grammar.
• [x I have read Contribution guidelines, maintainers note and Quality standard.
• My code is properly linted and passes pre-commit tests.

[fzipi]

Thanks @gantony for your contribution!

Feel free to keep reporting and sending PRs! 💪

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.68%. Comparing base (dcdbc28) to head (cfcf29e).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1259   +/-   ##
=======================================
  Coverage   81.68%   81.68%           
=======================================
  Files         168      168           
  Lines        9762     9765    +3     
=======================================
+ Hits         7974     7977    +3     
  Misses       1537     1537           
  Partials      251      251           

Flag	Coverage Δ
coraza.rule.case_sensitive_args_keys	81.64% <100.00%> (+<0.01%)	⬆️
coraza.rule.multiphase_valuation	81.68% <100.00%> (+<0.01%)	⬆️
coraza.rule.no_regex_multiline	81.62% <100.00%> (+<0.01%)	⬆️
default	81.68% <100.00%> (+<0.01%)	⬆️
examples+	16.54% <0.00%> (-0.01%)	⬇️
examples+coraza.rule.case_sensitive_args_keys	81.64% <100.00%> (+<0.01%)	⬆️
examples+coraza.rule.multiphase_valuation	81.52% <100.00%> (+<0.01%)	⬆️
examples+coraza.rule.no_regex_multiline	81.54% <100.00%> (+<0.01%)	⬆️
examples+memoize_builders	81.64% <100.00%> (+<0.01%)	⬆️
examples+no_fs_access	80.97% <100.00%> (+<0.01%)	⬆️
ftw	81.68% <100.00%> (+<0.01%)	⬆️
memoize_builders	81.78% <100.00%> (+<0.01%)	⬆️
no_fs_access	81.13% <100.00%> (+<0.01%)	⬆️
tinygo	81.65% <100.00%> (+<0.01%)	⬆️

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[jcchavezs]

Just to confirm, what is the behavior of modsec on this?

[fzipi]

• modsecv2 depends on apache, so it will have different behaviors based on which directive you are using, Include or IncludeOptional.
• libmodsecurity3: uses https://github.com/owasp-modsecurity/ModSecurity/blob/d9101a4fe14544f54f776aa5ae51d445938b3a12/src/utils/system.cc#L99 and returns an error if nothing is found. (no include optional in this case, as the inclusion is handled by the library).

I think this is the exact same behavior as the Include method above for both versions, and we should replicate.

There could be a new IncludeOptional directive if we want to add it, but that's for a followup issue + PR, IMHO.