Do not escape slashes in single quoted strings

libraries/apollo-ast/src/commonMain/kotlin/com/apollographql/apollo/ast/gqlstrings.kt

@@ -96,21 +96,27 @@ fun String.decodeAsGraphQLTripleQuoted(): String {
 }
 
 /**
- * https://spec.graphql.org/draft/#EscapedCharacter
+ * Escapes a single quoted string.
+ * The 2 mandatory characters to be escaped are `"` and `\`.
+ * For better readability, control codes are also escaped.
+ * Although `/` may be escaped, we leave it as is for better readability.
+ *
+ * See https://spec.graphql.org/draft/#sec-String-Value.Escape-Sequences.
+ * See https://en.wikipedia.org/wiki/List_of_Unicode_characters#Control_codes
  */
 fun String.encodeToGraphQLSingleQuoted(): String {
   return buildString {
     this@encodeToGraphQLSingleQuoted.forEach { c ->
       when (c) {
         '\"' -> append("\\\"")
         '\\' -> append("\\\\")
-        '/' -> append("\\/")
         '\b' -> append("\\b")
-        '\u000C' -> append("\\t")
+        '\u000C' -> append("\\f")
         '\n' -> append("\\n")
         '\r' -> append("\\r")
         '\t' -> append("\\t")
-        // TODO: handle range outside U+0020–U+FFFF
+        in '\u0000'..'\u001f' -> append("\\u00${c.code.toByte().hexString()}")
+        in '\u007f'..'\u009f' -> append("\\u00${c.code.toByte().hexString()}")
         else -> append(c)
       }
     }
@@ -134,3 +140,8 @@ fun String.encodeToGraphQLTripleQuoted(): String {
       }
 }
 
+private fun Byte.hexString(): String {
+  val hexArray = "0123456789abcdef"
+  val value = toInt()
+  return "${hexArray[value.ushr(4)]}${hexArray[value and 0x0F]}"
+}

libraries/apollo-ast/src/commonTest/kotlin/com/apollographql/apollo/graphql/ast/test/StringTest.kt

@@ -0,0 +1,17 @@
+package com.apollographql.apollo.graphql.ast.test
+
+import com.apollographql.apollo.ast.encodeToGraphQLSingleQuoted
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class StringTest {
+  @Test
+  fun slashesAreNotEscapedWhenWriting() {
+    assertEquals("rest/api/3/search", "rest/api/3/search".encodeToGraphQLSingleQuoted())
+  }
+
+  @Test
+  fun controlCodesAreEscaped() {
+    assertEquals("\\n\\u0003", "\n\u0003".encodeToGraphQLSingleQuoted())
+  }
+}