Omit empty unknown fields from toString (#181)

Author: pneckowicz-toast

protokt-codegen/src/main/kotlin/com/toasttab/protokt/codegen/annotators/MessageAnnotator.kt

@@ -206,21 +206,24 @@ private constructor(
                 .addModifiers(KModifier.OVERRIDE)
                 .addCode(
                     if (properties.isEmpty()) {
-                        "return \"${msg.name}(unknownFields=\$unknownFields)\""
+                        "return \"${msg.name}(${unknownFieldsToString(prefix = "")})\""
                     } else {
                         """
                             |return "${msg.name}(" +
                             |${toStringLines(properties)}
-                            |    "unknownFields=${"$"}unknownFields)"
+                            |    "${unknownFieldsToString(prefix = ", ")})"
                         """.bindMargin()
                     }
                 )
                 .build()
         )
 
+    private fun unknownFieldsToString(prefix: String) =
+        "\${if (unknownFields.isEmpty()) \"\" else \"${prefix}unknownFields=\$unknownFields\"}"
+
     private fun toStringLines(properties: List<PropertyInfo>) =
-        properties.joinToString("\n") {
-            "    \"${it.name}=\$${it.name}, \" +"
+        properties.joinToString(separator = ", \" +\n", postfix = "\" +") {
+            "    \"${it.name}=\$${it.name}"
         }.bindSpaces()
 
     private fun suppressDeprecation() =

protokt-runtime/src/main/kotlin/com/toasttab/protokt/rt/UnknownFieldSet.kt

@@ -22,6 +22,9 @@ private constructor(
     fun size() =
         unknownFields.entries.sumOf { (k, v) -> v.size(k) }
 
+    fun isEmpty() =
+        unknownFields.isEmpty()
+
     override fun equals(other: Any?) =
         other is UnknownFieldSet &&
             other.unknownFields == unknownFields

testing/runtime-tests/src/test/kotlin/com/toasttab/protokt/testing/rt/ToStringTest.kt

@@ -16,16 +16,55 @@
 package com.toasttab.protokt.testing.rt
 
 import com.google.common.truth.Truth.assertThat
+import com.toasttab.protokt.rt.UnknownField
+import com.toasttab.protokt.rt.UnknownFieldSet
 import org.junit.jupiter.api.Test
+import toasttab.protokt.testing.rt.Empty
 import toasttab.protokt.testing.rt.Test2
 
 class ToStringTest {
     @Test
-    fun `toString prints the correct format`() {
+    fun `toString prints the correct format for empty message`() {
+        assertThat(
+            Empty { }.toString()
+        ).isEqualTo(
+            "Empty()"
+        )
+    }
+
+    @Test
+    fun `toString prints the correct format for empty message with unknown fields`() {
+        assertThat(
+            Empty {
+                unknownFields = UnknownFieldSet.Builder().apply {
+                    add(UnknownField.fixed32(5, 10))
+                }.build()
+            }.toString()
+        ).isEqualTo(
+            "Empty(unknownFields=UnknownFieldSet(unknownFields={5=Field(varint=[], fixed32=[Fixed32Val(value=Fixed32(value=10))], fixed64=[], lengthDelimited=[])}))"
+        )
+    }
+
+    @Test
+    fun `toString omits unknown fields when empty`() {
         assertThat(
             Test2 { extra = "foo" }.toString()
         ).isEqualTo(
-            "Test2(`val`=[], extra=foo, unknownFields=UnknownFieldSet(unknownFields={}))"
+            "Test2(`val`=[], extra=foo)"
+        )
+    }
+
+    @Test
+    fun `toString prints the correct format with non-empty unknown fields`() {
+        assertThat(
+            Test2 {
+                extra = "foo"
+                unknownFields = UnknownFieldSet.Builder().apply {
+                    add(UnknownField.fixed32(5, 10))
+                }.build()
+            }.toString()
+        ).isEqualTo(
+            "Test2(`val`=[], extra=foo, unknownFields=UnknownFieldSet(unknownFields={5=Field(varint=[], fixed32=[Fixed32Val(value=Fixed32(value=10))], fixed64=[], lengthDelimited=[])}))"
         )
     }
 }