HPCC-33349 Roxie crash loading pre-9.8 queries with invalid regex

[dcamper]

Type of change:

• This change is a bug fix (non-breaking change which fixes an issue).
• This change is a new feature (non-breaking change which adds functionality).
• This change improves the code (refactor or other change that does not change the functionality)
• This change fixes warnings (the fix does not alter the functionality or the generated code)
• This change is a breaking change (fix or feature that will cause existing behavior to change).
• This change alters the query API (existing queries will have to be recompiled)

Checklist:

• My code follows the code style of this project.
  • My code does not create any new warnings from compiler, build system, or lint.
• The commit message is properly formatted and free of typos.
  • The commit message title makes sense in a changelog, by itself.
  • The commit is signed.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly, or...
  • I have created a JIRA ticket to update the documentation.
  • Any new interfaces or exported functions are appropriately commented.
• I have read the CONTRIBUTORS document.
• The change has been fully tested:
  • I have added tests to cover my changes.
  • All new and existing tests passed.
  • I have checked that this change does not introduce memory leaks.
  • I have used Valgrind or similar tools to check for potential issues.
• I have given due consideration to all of the following potential concerns:
  • Scalability
  • Performance
  • Security
  • Thread-safety
  • Cloud-compatibility
  • Premature optimization
  • Existing deployed queries will not be broken
  • This change fixes the problem, not just the symptom
  • The target branch of this pull request is appropriate for such a change.
• There are no similar instances of the same problem that should be addressed
  • I have addressed them here
  • I have raised JIRA issues to address them separately
• This is a user interface / front-end modification
  • I have tested my changes in multiple modern browsers
  • The component(s) render as expected

Smoketest:

• Send notifications about my Pull Request position in Smoketest queue.
• Test my draft Pull Request.

Testing:

Manually: Publish a query with a known-bad regex pattern to a 9.6.x cluster. Upgrade the cluster to 9.8.x. Ensure that Roxie does not crash and the query emits the correct error messages for the regex pattern failure.

[github-actions]

Jira Issue: https://hpccsystems.atlassian.net//browse/HPCC-33349

Jirabot Action Result:
Workflow Transition To: Merge Pending
Updated PR

[dcamper]

The basic idea of the changes in this PR are:

1. eclregex.cpp: Create static compileRegex() class methods with the sole task of compiling string patterns. They return the compiled patterns or throw an exception. Constructors now call the static methods to compile; if there is an error, capture the error description and squash the error to allow object construction.
2. eclregex.cpp: Methods check for a captured error description and throw an exception if found. Loosely, this defers the error that happened at object construction and surfaces it when someone tries to use it.
3. code generator: Use specific functions (that call the new static methods) to check regex syntax. This is cleaner than what was there before.

[ghalliday]

@dcamper thanks, the change looks good.
I have added one comment for a suggestion of a different implementation, but I am inclined to merge as-is since that has been tested. Are you happy with that?

[ghalliday]

One alternative implementation suggestion. You could have an Owned<IException> savedException member.

   catch (IException * e)
   {
      savedExceptions.setown(e);
   }

and

if (savedException)
    throw savedException.getLink();

[dcamper]

@ghalliday Saving exception rather than error description, as that is more in-line with platform style. Please recheck. Thanks!