Show error on missing Rascal dependency

[toinehartman]

Show errors while requesting a path config for projects Rascal projects without a dependency on Rascal.

Prerequisite for proper functioning of

• Remove std scheme rascal-language-servers#1159
• [POM-leading for DSLs] Server lifetime, bugs and simplification rascal-language-servers#1156

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 16.66667% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 46%. Comparing base (8fd6b5b) to head (0efba40).

Files with missing lines	Patch %	Lines
src/org/rascalmpl/library/util/PathConfig.java	16%	4 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2861   +/-   ##
=======================================
- Coverage       46%     46%   -1%     
+ Complexity    6766    6756   -10     
=======================================
  Files          841     841           
  Lines        67065   67071    +6     
  Branches     10020   10022    +2     
=======================================
- Hits         30880   30866   -14     
- Misses       33817   33833   +16     
- Partials      2368    2372    +4     

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[DavyLandman]

I'm a bit on the fence on this change. Since it requires all scenarios to have a pom.xml, which we don't always have, and normally we have a reasonable fallback there.

And what if some this code is used during construction of a REPL, than rascal should flow from the classpath of the REPL. So I'm not sure if we should make this an error at this level?

What are for example the effects of this change for:

• REPL startup in a project without a pom.xml
• REPL startup in a directory without a rascal project
• typechecking a project in VS Code that doesn't have a pom.xml

[toinehartman]

REPL startup in a directory without a rascal project

In this case, since path configs are only meant for source projects, I think a path config should not be built at all. So this error should not show.

a project without a pom.xml

Since this will result in an empty class path, it will raise the error. We could of course check if a POM exists and only show it in that case. Or we lower the level of the diagnostic to a warning, since indeed, we have reasonable default values for Rascal and Rascal LSP in case they are missing from the POM.

[DavyLandman]

In this case, since path configs are only meant for source projects, I think a path config should not be built at all. So this error should not show.

In ShellEvaluatorFactory::getDefaultEvaluatorForLocation (which is called by the REPL) we see that we try to guess the root path, and then ask for a path config of this root path.

But more importantly, we're already running rascal (namely our jar) so why are we giving an error/warning that there is no rascal defined?

Since this will result in an empty class path, it will raise the error. We could of course check if a POM exists and only show it in that case. Or we lower the level of the diagnostic to a warning, since indeed, we have reasonable default values for Rascal and Rascal LSP in case they are missing from the POM.

The more I think about this PR, the more I think, this should be a rascal-lsp warning/error, as that is the place we're building these path configs for "other" projects that our current JVM is running in.

[jurgenvinju]

This should be a warning because for backward compatibility we support projects that do not have the dependency.