Convert iterable of pairs to map, improve generic toMap(mutableMap) function #KT-4166 Fixed

libraries/stdlib/src/kotlin/collections/Exceptions.kt

@@ -1,3 +1,5 @@
 package kotlin
 
 public class EmptyIterableException(val it : Iterable<*>) : RuntimeException("$it is empty")
+
+public class DuplicateKeyException(val message : String = "Duplicate keys detected") : RuntimeException(message)

libraries/stdlib/src/kotlin/collections/Maps.kt

@@ -18,7 +18,7 @@ public fun <K, V> MutableMap<K, V>.set(key : K, value : V) : V? = this.put(key,
 
 /** Returns the [[Map]] if its not null otherwise it returns the empty [[Map]] */
 public fun <K,V> Map<K,V>?.orEmpty() : Map<K,V>
-= if (this != null) this else Collections.emptyMap<K,V>() as Map<K,V>
+= if (this != null) this else stdlib_emptyMap()
 
 public fun <K,V> Map<K,V>.contains(key : K) : Boolean = containsKey(key)
 
@@ -94,19 +94,39 @@ public inline fun <K,V,R,C: MutableMap<K,R>> Map<K,V>.mapValuesTo(result: C, tra
  * Puts all the entries into this [[MutableMap]] with the first value in the pair being the key and the second the value
  */
 public fun <K,V> MutableMap<K,V>.putAll(vararg values: Pair<K, V>): Unit {
-    for (v in values) {
-        put(v.first, v.second)
+    for ((key, value) in values) {
+        put(key, value)
     }
 }
 
 /**
  * Copies the entries in this [[Map]] to the given mutable *map*
  */
-public fun <K,V> Map<K,V>.toMap(map: MutableMap<K,V>): Map<K,V> {
+public fun <K,V, C : MutableMap<K, in V>> Map<K,V>.toMap(map: C): C {
     map.putAll(this)
     return map
 }
 
+/**
+ * Copies the entries from given iterable of pairs to the given mutable *map*
+ */
+public fun <K,V, C : MutableMap<K, in V>> Iterable<Pair<K,V>>.toMap(map: C): C {
+    for((key,value) in this) {
+        if (map.containsKey(key)) {
+            throw DuplicateKeyException()
+        }
+        map.put(key,value)
+    }
+    return map
+}
+
+/**
+ * Creates map from given iterable of pairs
+ */
+public fun <K,V> Iterable<Pair<K,V>>.toMap() : Map<K,V> {
+    return toMap(HashMap<K,V>())
+}
+
 /**
  * Returns a new Map containing the results of applying the given *transform* function to each [[Map.Entry]] in this [[Map]]
  *

libraries/stdlib/src/kotlin/collections/MapsJVM.kt

@@ -11,14 +11,14 @@ import java.util.Properties
 /**
  * Converts this [[Map]] to a [[LinkedHashMap]] so future insertion orders are maintained
  */
-public fun <K,V> Map<K,V>.toLinkedMap(): LinkedHashMap<K,V> = toMap<K,V>(LinkedHashMap(size)) as LinkedHashMap<K,V>
+public fun <K,V> Map<K,V>.toLinkedMap(): LinkedHashMap<K,V> = toMap(LinkedHashMap<K,V>(size))
 
 /**
  * Converts this [[Map]] to a [[SortedMap]] so iteration order will be in key order
  *
  * @includeFunctionBody ../../test/collections/MapTest.kt toSortedMap
  */
-public fun <K,V> Map<K,V>.toSortedMap(): SortedMap<K,V> = toMap<K,V>(TreeMap()) as SortedMap<K,V>
+public fun <K,V> Map<K,V>.toSortedMap(): SortedMap<K,V> = toMap(TreeMap<K,V>())
 
 /**
  * Converts this [[Map]] to a [[SortedMap]] using the given *comparator* so that iteration order will be in the order
@@ -26,7 +26,7 @@ public fun <K,V> Map<K,V>.toSortedMap(): SortedMap<K,V> = toMap<K,V>(TreeMap())
  *
  * @includeFunctionBody ../../test/collections/MapTest.kt toSortedMapWithComparator
  */
-public fun <K,V> Map<K,V>.toSortedMap(comparator: Comparator<K>): SortedMap<K,V> = toMap<K,V>(TreeMap(comparator)) as SortedMap<K,V>
+public fun <K,V> Map<K,V>.toSortedMap(comparator: Comparator<K>): SortedMap<K,V> = toMap(TreeMap<K,V>(comparator))
 
 
 /**

libraries/stdlib/test/collections/MapTest.kt

@@ -140,6 +140,13 @@ class MapTest {
         assertEquals(2, map.get("b"))
     }
 
+    test fun createFromIterable() {
+        val map = listOf(Pair("a", 1), Pair("b", 2)).toMap()
+        assertEquals(2, map.size)
+        assertEquals(1, map.get("a"))
+        assertEquals(2, map.get("b"))
+    }
+
     test fun createUsingTo() {
         val map = hashMapOf("a" to 1, "b" to 2)
         assertEquals(2, map.size)