[LUCENE-6245] ConstantScoreQuery etc have crazy toString()'s

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.1, 6.0
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Robert Muir
• Created: 14/Feb/15 05:24
• Updated: 28/Aug/22 14:25
• Resolved: 16/Feb/15 05:17

Description

For backwards compatibility reasons, LUCENE-1518 gave Filter a default "crap" toString(String) impl of getClass().getSimpleName(). I don't think we should do this. It causes problems e.g. when filters are wrapped in ConstantScoreQuery or other places, because toString(String) does the wrong thing.

Filter f = new MultiTermQueryWrapperFilter<WildcardQuery>(new WildcardQuery(new Term("foo", "b*ar")));
    
System.out.println(f.toString()); // foo:b*ar
System.out.println(f.toString("foo")); // MultiTermQueryWrapperFilter

Instead i think that impl should be removed (leaving it abstract), and Query.toString() should be final for a hard break:

  /** Prints a query to a string, with <code>field</code> assumed to be the 
   * default field and omitted.
   */
  public abstract String toString(String field);

  /** Prints a query to a string. */
  @Override
  public ****final**** String toString() {
    return toString("");
  }

having buggy toString's is worse than requiring a change in custom filters. It impacts all users rather than just expert ones. Also by doing this, all the current toString bugs in the codebase show up as compile errors.