[SPARK-10656][SQL] completely support special chars in DataFrame

the main problem is: we interpret column name with special handling of `.` for DataFrame. This enables us to write something like `df("a.b")` to get the field `b` of `a`. However, we don't need this feature in `DataFrame.apply("*")` or `DataFrame.withColumnRenamed`. In these 2 cases, the column name is the final name already, we don't need extra process to interpret it.

The solution is simple, use `queryExecution.analyzed.output` to get resolved column directly, instead of using `DataFrame.resolve`.

close #8811

Author: Wenchen Fan <[email protected]>

Closes #9462 from cloud-fan/special-chars.

Author: cloud-fan

sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala

@@ -698,7 +698,7 @@ class DataFrame private[sql](
    */
   def col(colName: String): Column = colName match {
     case "*" =>
-      Column(ResolvedStar(schema.fieldNames.map(resolve)))
+      Column(ResolvedStar(queryExecution.analyzed.output))
     case _ =>
       val expr = resolve(colName)
       Column(expr)
@@ -1259,13 +1259,17 @@ class DataFrame private[sql](
    */
   def withColumnRenamed(existingName: String, newName: String): DataFrame = {
     val resolver = sqlContext.analyzer.resolver
-    val shouldRename = schema.exists(f => resolver(f.name, existingName))
+    val output = queryExecution.analyzed.output
+    val shouldRename = output.exists(f => resolver(f.name, existingName))
     if (shouldRename) {
-      val colNames = schema.map { field =>
-        val name = field.name
-        if (resolver(name, existingName)) Column(name).as(newName) else Column(name)
+      val columns = output.map { col =>
+        if (resolver(col.name, existingName)) {
+          Column(col).as(newName)
+        } else {
+          Column(col)
+        }
       }
-      select(colNames : _*)
+      select(columns : _*)
     } else {
       this
     }

sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala

@@ -1128,4 +1128,10 @@ class DataFrameSuite extends QueryTest with SharedSQLContext {
       }
     }
   }
+
+  test("SPARK-10656: completely support special chars") {
+    val df = Seq(1 -> "a").toDF("i_$.a", "d^'a.")
+    checkAnswer(df.select(df("*")), Row(1, "a"))
+    checkAnswer(df.withColumnRenamed("d^'a.", "a"), Row(1, "a"))
+  }
 }