[LUCENE-4793] Spellchecker don't find suggestion for concrete misspelled 6 letter words

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 3.6, 4.0, 4.1
• Component/s: modules/spellchecker
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Samuel García Martínez
• Created: 21/Feb/13 21:26
• Updated: 28/Aug/22 13:39

Description

Debugging Solr spellchecker (IndexBasedSpellchecker, delegating on lucene Spellchecker) behaviour i think i found a bug when the input is a 6 letter word:

• george
• anthem
• argued
• fluent

Due to the getMin() and getMax() the grams indexed for these terms are 3 and 4. So, the fields would be something like this:

• for "george"
  • start3: "geo"
  • start4: "geor"
  • end3: "rge"
  • end4: "orge"
  • 3: "geo", "eor", "org", "rge"
  • 4: "geor", "eorg", "orge"
• for "anthem"
  • start3: "ant"
  • start4: "anth"
  • end3: "tem"
  • end4: "them"

The problem shows up when the user swap 3rd a 4th characters, misspelling the word like this:

• geroge
• anhtem

The queries generated for this terms are: (SHOULD boolean queries)

• for "geroge"
  • start3: "ger"
  • start4: "gero"
  • end3: "oge"
  • end4: "roge"
  • 3: "ger", "ero", "rog", "oge"
  • 4: "gero", "erog", "roge"
• for "anhtem"
  • start3: "anh"
  • start4: "anht"
  • end3: "tem"
  • end4: "htem"
  • 3: "anh", "nht", "hte", "tem"
  • 4: "anht", "nhte", "htem"

So, as you can see, this kind of misspelling never matches the suitable suggestions although the edit distance is 0.95555556.

I think getMin(int l) and getMax(int l) should return 2 and 3, respectively, for l==6. Debugging other values i did not found any problem with any kind of misspelling.