[calcite] branch master updated: [CALCITE-3172] RelBuilder#empty does not keep aliases

[ru...@apache.org]

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rubenql pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/calcite.git


The following commit(s) were added to refs/heads/master by this push:
     new 046f9f4  [CALCITE-3172] RelBuilder#empty does not keep aliases
046f9f4 is described below

commit 046f9f4e2e3c779e4e2e61946d67a0dc124f7f72
Author: rubenada <ru...@gmail.com>
AuthorDate: Thu Jul 4 16:06:41 2019 +0200

    [CALCITE-3172] RelBuilder#empty does not keep aliases
---
 .../java/org/apache/calcite/tools/RelBuilder.java  |  7 +++-
 .../org/apache/calcite/test/RelBuilderTest.java    | 44 ++++++++++++++++++++++
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/apache/calcite/tools/RelBuilder.java b/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
index cdf71c4..c8545ed 100644
--- a/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
+++ b/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
@@ -2096,14 +2096,17 @@ public class RelBuilder {
    * expressions, and always produces a leaf.
    *
    * <p>The default implementation creates a {@link Values} with the same
-   * specified row type as the input, and ignores the input entirely.
+   * specified row type and aliases as the input, and ignores the input entirely.
    * But schema-on-query systems such as Drill might override this method to
    * create a relation expression that retains the input, just to read its
    * schema.
    */
   public RelBuilder empty() {
     final Frame frame = stack.pop();
-    return values(frame.rel.getRowType());
+    final RelNode values =
+        valuesFactory.createValues(cluster, frame.rel.getRowType(), ImmutableList.of());
+    stack.push(new Frame(values, frame.fields));
+    return this;
   }
 
   /** Creates a {@link Values} with a specified row type.
diff --git a/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java b/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
index c06bdeb..a71ce05 100644
--- a/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
+++ b/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
@@ -2042,6 +2042,50 @@ public class RelBuilderTest {
     assertThat(root.getRowType().getFullTypeString(), is(expectedType));
   }
 
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-3172">[CALCITE-3172]
+   * RelBuilder#empty does not keep aliases</a>. */
+  @Test public void testEmptyWithAlias() {
+    final RelBuilder builder = RelBuilder.create(config().build());
+    final String expected =
+        "LogicalProject(DEPTNO=[$0], DNAME=[$1])\n  LogicalValues(tuples=[[]])\n";
+    final String expectedType =
+        "RecordType(TINYINT NOT NULL DEPTNO, VARCHAR(14) DNAME) NOT NULL";
+
+    // Scan + Empty + Project (without alias)
+    RelNode root =
+        builder.scan("DEPT")
+            .empty()
+            .project(
+                builder.field("DEPTNO"),
+                builder.field("DNAME"))
+            .build();
+    assertThat(root, hasTree(expected));
+    assertThat(root.getRowType().getFullTypeString(), is(expectedType));
+
+    // Scan + Empty + Project (with alias)
+    root =
+        builder.scan("DEPT").as("d")
+            .empty()
+            .project(
+                builder.field(1, "d", "DEPTNO"),
+                builder.field(1, "d", "DNAME"))
+            .build();
+    assertThat(root, hasTree(expected));
+    assertThat(root.getRowType().getFullTypeString(), is(expectedType));
+
+    // Scan + Filter false (implicitly converted into Empty) + Project (with alias)
+    root =
+        builder.scan("DEPT").as("d")
+            .filter(builder.literal(false))
+            .project(
+                builder.field(1, "d", "DEPTNO"),
+                builder.field(1, "d", "DNAME"))
+            .build();
+    assertThat(root, hasTree(expected));
+    assertThat(root.getRowType().getFullTypeString(), is(expectedType));
+  }
+
   @Test public void testValues() {
     // Equivalent SQL:
     //   VALUES (true, 1), (false, -50) AS t(a, b)