pi-lens/rules/tree-sitter-queries/java/main-should-not-throw.yml

Real-time code feedback for pi — LSP, linters, formatters, type-checking, structural analysis & booboo

# Main Should Not Throw
# Detects main methods that declare throws clause
id: main-should-not-throw
name: Main Method Should Not Throw
severity: warning
category: reliability
defect_class: correctness
inline_tier: blocking
language: java

message: "main() should not declare throws — handle exceptions internally"

description: |
  The main() method should not throw exceptions. Instead, handle
  exceptions within main and exit with an appropriate status code.
  Throwing from main leaves error handling to the JVM.

  ✅ FIX: Wrap in try-catch and exit gracefully

  ```java
  public static void main(String[] args) {
      try {
          runApplication(args);
      } catch (Exception e) {
          System.err.println("Error: " + e.getMessage());
          System.exit(1);
      }
  }
  ```

query: |
  (method_declaration
    (modifiers
      "static")
    name: (identifier) @NAME (#eq? @NAME "main")
    (throws) @THROWS)

metavars:
  - NAME
  - THROWS

tags:
  - reliability
  - java
  - error-handling
  - entry-point

examples:
  bad: |
    public static void main(String[] args) throws Exception {  // BAD
        runApp(args);
    }

  good: |
    public static void main(String[] args) {
        try {
            runApp(args);
        } catch (Exception e) {
            System.exit(1);  // GOOD - handle in main
        }
    }

has_fix: false