Quote enum item names when necessary (#241) (#242)

Add backticks to the enum item name in case it doesn't
start with a letter or an underscore and hence is not
a valid Kotlin identifier.

src/main/kotlin/com/cjbooms/fabrikt/generators/OasDefault.kt

@@ -1,7 +1,7 @@
 package com.cjbooms.fabrikt.generators
 
 import com.cjbooms.fabrikt.model.KotlinTypeInfo
-import com.cjbooms.fabrikt.util.toUpperCase
+import com.cjbooms.fabrikt.util.NormalisedString.toEnumName
 import com.squareup.kotlinpoet.ClassName
 import com.squareup.kotlinpoet.CodeBlock
 import com.squareup.kotlinpoet.TypeName
@@ -39,7 +39,7 @@ sealed class OasDefault {
 
     data class EnumValue(val type: TypeName, val enumValue: String) : OasDefault() {
         override fun getDefault(): CodeBlock =
-            CodeBlock.of("%T.${enumValue.toUpperCase()}", type)
+            CodeBlock.of("%T.${enumValue.toEnumName()}", type)
     }
 
     data class JsonNullableValue(val inner: OasDefault) : OasDefault() {

src/main/kotlin/com/cjbooms/fabrikt/util/NormalisedString.kt

@@ -30,6 +30,7 @@ object NormalisedString {
         replaceSpecialCharacters()
             .camelToSnake()
             .toUpperCase()
+            .quoteIfNotValidIdentifier()
 
     fun String.toKotlinParameterName(): String = this.camelCase()
 
@@ -42,4 +43,5 @@ object NormalisedString {
 fun String.toUpperCase() = uppercase(Locale.getDefault())
 fun String.toLowerCase() = lowercase(Locale.getDefault())
 fun String.capitalized() = replaceFirstChar { if (it.isLowerCase()) it.titlecase(Locale.getDefault()) else it.toString() }
-fun String.decapitalized() = replaceFirstChar { it.lowercase(Locale.getDefault()) }
+fun String.decapitalized() = replaceFirstChar { it.lowercase(Locale.getDefault()) }
+fun String.quoteIfNotValidIdentifier() = if (first().isLetter() || first() == '_') this else "`$this`"

src/test/kotlin/com/cjbooms/fabrikt/util/NormalisedStringTest.kt

@@ -49,4 +49,14 @@ class NormalisedStringTest {
         assertThat("PascalCase_åØÆÅ_enumWith-special/characters.json".toEnumName())
             .isEqualTo("PASCAL_CASE_Å_ØÆÅ_ENUM_WITH_SPECIAL_CHARACTERS_JSON")
     }
+
+    @Test
+    fun `toEnumName should backtick enum if it starts with non-letter character`() {
+        assertThat("42".toEnumName()).isEqualTo("`42`")
+    }
+
+    @Test
+    fun `toEnumName should not backtick enum if it starts with underscore character`() {
+        assertThat("_42".toEnumName()).isEqualTo("_42")
+    }
 }

src/test/resources/examples/defaultValues/api.yaml

@@ -18,6 +18,12 @@ components:
             - tall
             - short
           default: tall
+        enum_quoted_default:
+          type: string
+          enum:
+            - 1x
+            - 2x
+          default: 2x
         boolean_default:
           type: boolean
           default: true

src/test/resources/examples/defaultValues/models/Models.kt

@@ -24,6 +24,11 @@ public data class PersonWithDefaults(
     @get:JsonProperty("enum_default")
     @get:NotNull
     public val enumDefault: PersonWithDefaultsEnumDefault = PersonWithDefaultsEnumDefault.TALL,
+    @param:JsonProperty("enum_quoted_default")
+    @get:JsonProperty("enum_quoted_default")
+    @get:NotNull
+    public val enumQuotedDefault: PersonWithDefaultsEnumQuotedDefault =
+        PersonWithDefaultsEnumQuotedDefault.`2X`,
     @param:JsonProperty("boolean_default")
     @get:JsonProperty("boolean_default")
     @get:NotNull
@@ -57,3 +62,19 @@ public enum class PersonWithDefaultsEnumDefault(
         public fun fromValue(`value`: String): PersonWithDefaultsEnumDefault? = mapping[value]
     }
 }
+
+public enum class PersonWithDefaultsEnumQuotedDefault(
+    @JsonValue
+    public val `value`: String,
+) {
+    `1X`("1x"),
+    `2X`("2x"),
+    ;
+
+    public companion object {
+        private val mapping: Map<String, PersonWithDefaultsEnumQuotedDefault> =
+            values().associateBy(PersonWithDefaultsEnumQuotedDefault::value)
+
+        public fun fromValue(`value`: String): PersonWithDefaultsEnumQuotedDefault? = mapping[value]
+    }
+}

src/test/resources/examples/enumExamples/api.yaml

@@ -40,6 +40,9 @@ components:
         - one
         - two
         - three
+        - 4
+        - -5
+        - _6
 
     ExtensibleEnumObject:
       type: string

src/test/resources/examples/enumExamples/models/Models.kt

@@ -107,6 +107,9 @@ public enum class EnumObject(
     ONE("one"),
     TWO("two"),
     THREE("three"),
+    `4`("4"),
+    _5("-5"),
+    _6("_6"),
     ;
 
     public companion object {