Quote integer-like map keys in JsonPath to properly distinguish them …

…from array indicies
Kotlin · Mar 21, 2022 · 358e1a5 · 358e1a5
1 parent 85dce74
commit 358e1a5
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Showing 2 changed files with 15 additions and 5 deletions.
diff --git a/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonPath.kt b/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonPath.kt
@@ -2,6 +2,7 @@ package kotlinx.serialization.json.internal
 
 import kotlinx.serialization.*
 import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.internal.*
 
 /**
  * Internal representation of the current JSON path.
@@ -20,6 +21,9 @@ import kotlinx.serialization.descriptors.*
  * ```
  */
 internal class JsonPath {
+
+    // Tombstone indicates that we are within a map, but the map key is currently being decoded.
+    // It is also used to overwrite a previous map key to avoid memory leaks and misattribution.
     object Tombstone
 
     /*
@@ -68,6 +72,7 @@ internal class JsonPath {
         indicies[currentDepth] = -2
     }
 
+    /** Used to indicate that we are in the process of decoding the key itself and can't specify it in path */
     fun resetCurrentMapKey() {
         if (indicies[currentDepth] == -2) {
             currentObjectPath[currentDepth] = Tombstone
@@ -111,8 +116,13 @@ internal class JsonPath {
                     }
                 } else if (element !== Tombstone) {
                     append("[")
-                    // Else -- structured key
+                    // With this check numbers keys will be quoted,
+                    // so both [42] and ['42'] are now non ambiguous
+                    val isNumberKey = element is Number
+                    if (isNumberKey) append("'")
+                    // Else -- map key
                     append(element)
+                    if (isNumberKey) append("'")
                     append("]")
                 }
             }

diff --git a/formats/json/commonTest/src/kotlinx/serialization/JsonPathTest.kt b/formats/json/commonTest/src/kotlinx/serialization/JsonPathTest.kt
@@ -29,7 +29,7 @@ class JsonPathTest : JsonTestBase() {
 
     @Test
     fun testMissingKey() {
-        expectPath("$.i.d[1]") { Json.decodeFromString<Outer>("""{"a":42, "i":{"d":{1:{}}""") }
+        expectPath("$.i.d['1']") { Json.decodeFromString<Outer>("""{"a":42, "i":{"d":{1:{}}""") }
     }
 
     @Test
@@ -76,9 +76,9 @@ class JsonPathTest : JsonTestBase() {
 
     @Test
     fun testMapValue() {
-        expectPath("$.i.d[42]\n") { Json.decodeFromString<Outer>("""{"a":42, "i":{ "d": {42: {"xx":"bar"}}""") }
-        expectPath("$.i.d[43]\n") { Json.decodeFromString<Outer>("""{"a":42, "i":{ "d": {42: {"s":"s"}, 43: {"xx":"bar"}}}""") }
-        expectPath("$[239]") { Json.decodeFromString<Map<Int, String>>("""{239:bar}""") }
+        expectPath("$.i.d['42']\n") { Json.decodeFromString<Outer>("""{"a":42, "i":{ "d": {42: {"xx":"bar"}}""") }
+        expectPath("$.i.d['43']\n") { Json.decodeFromString<Outer>("""{"a":42, "i":{ "d": {42: {"s":"s"}, 43: {"xx":"bar"}}}""") }
+        expectPath("$['239']") { Json.decodeFromString<Map<Int, String>>("""{239:bar}""") }
     }
 
     @Serializable