[apex] New rule for empty statements

[oowekyala]

Proposed Rule Name: EmptyStatement, probably

Proposed Category: Best Practices

Description: Would flag empty blocks and statements like if or else that have an empty body.

See #3164 (comment)

Thanks for the report. There's an identical ticket for the java rules (#3096). Like in the java module, I think we should just make a single rule that flags empty blocks and statements, and remove EmptyIfStmt and the others, which would be covered by this single rule. Relevant rules: EmptyCatchBlock, EmptyIfStmt, EmptyStatementBlock, EmptyTryOrFinallyBlock, EmptyWhileStmt

See #3641 (review):

What we should do instead is the following (as outlined in the comment on #3164):

1. Create a new rule combines all the Empty* rules that are already existing.
2. Deprecate all the Empty* rules in favor of the new rule
3. Use the new rule in quickstart.xml instead of the now deprecated rules
4. In PMD7 delete all the deprecated Empty* rules

Related issues:

• Would fix [apex] Duplicate warning for EmptyStatementBlock and EmptyIfStmt #3164
• Would supersede [apex] added fix to not tag single block for two error statements #3641
• See also effort in the Java module to do the same thing:
  • [java] EmptyStatementNotInLoop FP in 6.30.0 with IfStatement #3096 (comment)
  • [java] Merge rules that check for empty things #3716

Code Sample: See tests of existing rules

Possible Properties: None