Levenshtein: change how ratio is computed

Don't subtract the length difference from distance, as that leads to low numbers (frequently, zero) on pairs which are quite dissimilar. Instead, divide by the length of the longer of the two.
scalameta · May 23, 2021 · 05ae159 · 05ae159
1 parent d47046d
commit 05ae159
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diff --git a/metaconfig-core/shared/src/main/scala/metaconfig/internal/Levenshtein.scala b/metaconfig-core/shared/src/main/scala/metaconfig/internal/Levenshtein.scala
@@ -7,10 +7,8 @@ object Levenshtein {
       candidates: Seq[String]
   ): Option[String] = {
     val candidatesWithRatio = candidates.flatMap { candidate =>
-      val minDifference = math.abs(query.length() - candidate.length())
-      val difference = distance(candidate)(query).toDouble - minDifference
-      val ratio = difference.toDouble /
-        math.min(query.length(), candidate.length())
+      val levDist = distance(candidate)(query).toDouble
+      val ratio = levDist / math.max(query.length(), candidate.length())
       if (ratio < 0.4) Some((candidate, ratio))
       else None // Don't return candidate when difference is large.
     }

diff --git a/metaconfig-tests/jvm/src/test/scala/metaconfig/cli/CliParserSuite.scala b/metaconfig-tests/jvm/src/test/scala/metaconfig/cli/CliParserSuite.scala
@@ -287,55 +287,51 @@ class CliParserSuite extends BaseCliParserSuite {
     "skip hidden",
     "--hidden1" :: "10" :: Nil,
     """|found argument '--hidden1' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--in'?
        |""".stripMargin
   )
 
   checkError(
     "match decoding",
     "--decoding" :: "10" :: Nil,
     """|found argument '--decoding' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--in'?
+       |	Did you mean '--encoding'?
        |""".stripMargin
   )
 
   checkError(
     "match decodung",
     "--decodung" :: "10" :: Nil,
     """|found argument '--decodung' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--conf'?
+       |	Did you mean '--encoding'?
        |""".stripMargin
   )
 
   checkError(
     "match decodingg",
     "--decodingg" :: "10" :: Nil,
     """|found argument '--decodingg' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--in'?
+       |	Did you mean '--encoding'?
        |""".stripMargin
   )
 
   checkError(
     "match decoddung",
     "--decoddung" :: "10" :: Nil,
     """|found argument '--decoddung' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--conf'?
        |""".stripMargin
   )
 
   checkError(
     "match decodding1",
     "--decodding1" :: "10" :: Nil,
     """|found argument '--decodding1' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--in'?
        |""".stripMargin
   )
 
   checkError(
     "match decodunk",
     "--decodunk" :: "10" :: Nil,
     """|found argument '--decodunk' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--conf'?
        |""".stripMargin
   )
 

diff --git a/metaconfig-tests/jvm/src/test/scala/metaconfig/cli/SubcommandSuite.scala b/metaconfig-tests/jvm/src/test/scala/metaconfig/cli/SubcommandSuite.scala
@@ -160,7 +160,6 @@ class SubcommandSuite extends FunSuite {
   checkError(
     List("test", "--max=40"),
     """|error: found argument '--max' which wasn't expected, or isn't valid in this context.
-       |	Did you mean '--max-count'?
        |""".stripMargin
   )
   checkError(