Levenshtein: as fallback, look for prefix option

scalameta · May 23, 2021 · cf69d53 · cf69d53
1 parent 05ae159
commit cf69d53
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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
@@ -13,7 +13,17 @@ object Levenshtein {
       else None // Don't return candidate when difference is large.
     }
     val result = candidatesWithRatio.sortBy(_._2).headOption.map(_._1)
-    result
+    result.orElse(prefixCandidate(query, candidates))
+  }
+
+  private def prefixCandidate(
+      query: String,
+      candidates: Seq[String]
+  ): Option[String] = {
+    val prefixCandidates = candidates.flatMap { candidate =>
+      if (candidate.startsWith(query)) Some(candidate) else None
+    }
+    Option(prefixCandidates).filter(_.length == 1).map(_.head)
   }
 
   /** Levenshtein distance. Implementation based on Wikipedia's algorithm. */

diff --git a/metaconfig-tests/jvm/src/test/scala/metaconfig/cli/SubcommandSuite.scala b/metaconfig-tests/jvm/src/test/scala/metaconfig/cli/SubcommandSuite.scala
@@ -160,6 +160,7 @@ 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(