Avoid hitting max argument limit in String(chars)

Rewrite CharArray to String conversions to appending chars one by one.

Refine parameter checking in String(chars, offset, length) to adhere to
the common exception contract and document it.

#KT-29003

libraries/stdlib/common/src/kotlin/TextH.kt

@@ -100,6 +100,9 @@ public expect fun String(chars: CharArray): String
 
 /**
  * Converts the characters from a portion of the specified array to a string.
+ *
+ * @throws IndexOutOfBoundsException if either [offset] or [length] are less than zero
+ * or `offset + length` is out of [chars] array bounds.
  */
 @SinceKotlin("1.2")
 public expect fun String(chars: CharArray, offset: Int, length: Int): String

libraries/stdlib/js/src/kotlin/string.kt

@@ -11,17 +11,29 @@ import kotlin.js.RegExp
  * Converts the characters in the specified array to a string.
  */
 @SinceKotlin("1.2")
-@kotlin.internal.InlineOnly
-public actual inline fun String(chars: CharArray): String {
-    return js("String.fromCharCode").apply(null, chars)
+public actual fun String(chars: CharArray): String {
+    var result = ""
+    for (char in chars) {
+        result += char
+    }
+    return result
 }
 
 /**
  * Converts the characters from a portion of the specified array to a string.
+ *
+ * @throws IndexOutOfBoundsException if either [offset] or [length] are less than zero
+ * or `offset + length` is out of [chars] array bounds.
  */
 @SinceKotlin("1.2")
 public actual fun String(chars: CharArray, offset: Int, length: Int): String {
-    return String(chars.copyOfRange(offset, offset + length))
+    if (offset < 0 || length < 0 || chars.size - offset < length)
+        throw IndexOutOfBoundsException("size: ${chars.size}; offset: $offset; length: $length")
+    var result = ""
+    for (index in offset until offset + length) {
+        result += chars[index]
+    }
+    return result
 }
 
 /**

libraries/stdlib/jvm/src/kotlin/text/StringsJVM.kt

@@ -272,6 +272,9 @@ public actual inline fun String(chars: CharArray): String =
 
 /**
  * Converts the characters from a portion of the specified array to a string.
+ *
+ * @throws IndexOutOfBoundsException if either [offset] or [length] are less than zero
+ * or `offset + length` is out of [chars] array bounds.
  */
 @kotlin.internal.InlineOnly
 public actual inline fun String(chars: CharArray, offset: Int, length: Int): String =

libraries/stdlib/test/text/StringTest.kt

@@ -53,11 +53,21 @@ class StringTest {
     @Test fun stringFromCharArraySlice() {
         val chars: CharArray = charArrayOf('K', 'o', 't', 'l', 'i', 'n', ' ', 'r', 'u', 'l', 'e', 's')
         assertEquals("rule", String(chars, 7, 4))
+
+        val longChars = CharArray(200_000) { 'k' }
+        val longString = String(longChars, 1000, 190_000)
+        assertEquals(190_000, longString.length)
+        assertTrue(longString.all { it == 'k' })
     }
 
     @Test fun stringFromCharArray() {
         val chars: CharArray = charArrayOf('K', 'o', 't', 'l', 'i', 'n')
         assertEquals("Kotlin", String(chars))
+
+        val longChars = CharArray(200_000) { 'k' }
+        val longString = String(longChars)
+        assertEquals(200_000, longString.length)
+        assertTrue(longString.all { it == 'k' })
     }
 
     @Test fun stringFromCharArrayUnicodeSurrogatePairs() {
@@ -67,6 +77,16 @@ class StringTest {
         assertEquals("Ŭᎍ🀺", String(chars, 3, 4))
     }
 
+    @Test fun stringFromCharArrayOutOfBounds() {
+        fun test(chars: CharArray) {
+            assertFailsWith<IndexOutOfBoundsException> { String(chars, -1, 1) }
+            assertFailsWith<IndexOutOfBoundsException> { String(chars, 1, -1) }
+            assertFailsWith<IndexOutOfBoundsException> { String(chars, chars.size - 1, 2) }
+        }
+        test(CharArray(16) { 'k' })
+        test(CharArray(160_000) { 'k' })
+    }
+
     @Test fun isEmptyAndBlank() = withOneCharSequenceArg { arg1 ->
         class Case(val value: String?, val isNull: Boolean = false, val isEmpty: Boolean = false, val isBlank: Boolean = false)