Check for invalid missing "then" in case expressions

Author: jeffgbutler

src/main/kotlin/org/mybatis/dynamic/sql/util/kotlin/elements/CaseDSLs.kt

@@ -22,6 +22,7 @@ import org.mybatis.dynamic.sql.select.caseexpression.ConditionBasedWhenCondition
 import org.mybatis.dynamic.sql.select.caseexpression.SearchedCaseWhenCondition
 import org.mybatis.dynamic.sql.select.caseexpression.SimpleCaseWhenCondition
 import org.mybatis.dynamic.sql.util.kotlin.GroupingCriteriaCollector
+import org.mybatis.dynamic.sql.util.kotlin.assertNotNull
 import org.mybatis.dynamic.sql.util.kotlin.assertNull
 
 class KSearchedCaseDSL : KElseDSL {
@@ -34,9 +35,10 @@ class KSearchedCaseDSL : KElseDSL {
 
     fun `when`(dslCompleter: SearchedCaseCriteriaCollector.() -> Unit) =
         SearchedCaseCriteriaCollector().apply(dslCompleter).run {
+            assertNotNull(thenValue, "ERROR.47") //$NON-NLS-1$
             whenConditions.add(SearchedCaseWhenCondition.Builder().withInitialCriterion(initialCriterion)
                 .withSubCriteria(subCriteria)
-                .withThenValue(thenValue)
+                .withThenValue(thenValue!!)
                 .build())
         }
 

src/main/resources/org/mybatis/dynamic/sql/util/messages.properties

@@ -63,4 +63,5 @@ ERROR.43=A Kotlin cast expression must have one, and only one, `as` element
 ERROR.44={0} conditions must contain at least one value
 ERROR.45=You cannot call "on" in a Kotlin join expression more than once
 ERROR.46=At least one join criterion must render
+ERROR.47=A Kotlin case statement must specify a "then" clause for every "when" clause
 INTERNAL.ERROR=Internal Error {0}

src/test/kotlin/examples/kotlin/animal/data/KCaseExpressionTest.kt

@@ -922,6 +922,17 @@ class KCaseExpressionTest {
         }.withMessage(Messages.getString("ERROR.41"))
     }
 
+    @Test
+    fun testInvalidMissingThen() {
+        assertThatExceptionOfType(KInvalidSQLException::class.java).isThrownBy {
+            case {
+                `when` {
+                    id isEqualTo 22
+                }
+            }
+        }.withMessage(Messages.getString("ERROR.47"))
+    }
+
     @Test
     fun testInvalidSearchedMissingWhen() {
         assertThatExceptionOfType(InvalidSqlException::class.java).isThrownBy {