Throw IllegalArgumentException with meaningful message for missing format arguments

Author: Wojciech Liberda

components/resources/library/src/commonMain/kotlin/org/jetbrains/compose/resources/StringResourcesUtils.kt

@@ -19,7 +19,11 @@ internal fun String.replaceWithArgs(args: List<String>): String {
                 )
             }
         }
-        args[index]
+        args.getOrElse(index) {
+            throw IllegalArgumentException(
+                "Formatting failed: Placeholder '${match.value}' at position ${index + 1} is out of bounds. Only ${args.size} argument(s) provided for format string \"$this\""
+            )
+        }
     }
 }
 
@@ -30,14 +34,10 @@ internal sealed interface StringItem {
 }
 
 private val stringItemsCache = AsyncCache<String, StringItem>()
-//@TestOnly
-internal fun dropStringItemsCache() {
-    stringItemsCache.clear()
-}
 
 internal suspend fun getStringItem(
     resourceItem: ResourceItem,
-    resourceReader: ResourceReader
+    resourceReader: ResourceReader,
 ): StringItem = stringItemsCache.getOrLoad(
     key = "${resourceItem.path}/${resourceItem.offset}-${resourceItem.size}"
 ) {

components/resources/library/src/commonTest/kotlin/org/jetbrains/compose/resources/StringFormatTest.kt

@@ -16,6 +16,10 @@ class StringFormatTest {
 
         assertEquals("Hello Alice, you have 5 new messages!", result)
     }
+    //@TestOnly
+    internal fun dropStringItemsCache() {
+        stringItemsCache.clear()
+    }
 
     @Test
     fun `replaceWithArgs works with multiple placeholders referring to the same argument`() {
@@ -52,9 +56,13 @@ class StringFormatTest {
         val template = "Hello %1\$s, %2\$s!"
         val args = listOf("Alice")
 
-        assertFailsWith<IndexOutOfBoundsException> {
+        val exception = assertFailsWith<IllegalArgumentException> {
             template.replaceWithArgs(args)
         }
+        assertEquals(
+            "Formatting failed: Placeholder '%2\$s' at position 2 is out of bounds. Only 1 argument(s) provided for format string \"Hello %1\$s, %2\$s!\"",
+            exception.message
+        )
     }
 
     @Test
@@ -72,9 +80,13 @@ class StringFormatTest {
         val template = "Hello %1\$s, you have %3\$s messages"
         val args = listOf("Alice")
 
-        assertFailsWith<IndexOutOfBoundsException> {
+        val exception = assertFailsWith<IllegalArgumentException> {
             template.replaceWithArgs(args)
         }
+        assertEquals(
+            "Formatting failed: Placeholder '%3\$s' at position 3 is out of bounds. Only 1 argument(s) provided for format string \"Hello %1\$s, you have %3\$s messages\"",
+            exception.message
+        )
     }
 
     @Test
@@ -137,26 +149,34 @@ class StringFormatTest {
     }
 
     @Test
+    @IgnoreWasmTest // https://youtrack.jetbrains.com/issue/KT-69014, wasm throws RuntimeError instead of IndexOutOfBounds
     fun `replaceWithArgs throws exception for missing arguments`() {
         val template = "Hello %1\$s, you have %2\$d messages!"
         val args = listOf("Alice")
 
         // An exception should be thrown because the second argument (%2$d) is missing
-        assertFailsWith<IndexOutOfBoundsException> {
+        val exception = assertFailsWith<IllegalArgumentException> {
             template.replaceWithArgs(args)
         }
+        assertEquals(
+            "Formatting failed: Placeholder '%2\$d' at position 2 is out of bounds. Only 1 argument(s) provided for format string \"Hello %1\$s, you have %2\$d messages!\"",
+            exception.message
+        )
     }
 
     @Test
-    @IgnoreWasmTest // https://youtrack.jetbrains.com/issue/KT-69014, wasm throws RuntimeError instead of IndexOutOfBounds
     fun `replaceWithArgs throws exception for unmatched placeholders`() {
         val template = "Hello %1\$s, your rank is %3\$s"
         val args = listOf("Alice", "1")
 
         // The template has a %3$s placeholder, but there is no third argument
-        assertFailsWith<IndexOutOfBoundsException> {
+        val exception = assertFailsWith<IllegalArgumentException> {
             template.replaceWithArgs(args)
         }
+        assertEquals(
+            "Formatting failed: Placeholder '%3\$s' at position 3 is out of bounds. Only 2 argument(s) provided for format string \"Hello %1\$s, your rank is %3\$s\"",
+            exception.message
+        )
     }
 
     @Test