Add tuple() method to Skylark.

This method coerces any collection to a Skylark tuple, analogous to list() or set().

--
PiperOrigin-RevId: 141779268
MOS_MIGRATED_REVID=141779268

2 files changed, 11 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/syntax/EnvironmentTest.java b/src/test/java/com/google/devtools/build/lib/syntax/EnvironmentTest.java
index 155385d440..a642f63879 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/EnvironmentTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/EnvironmentTest.java
@@ -145,6 +145,7 @@ public class EnvironmentTest extends EvaluationTestCase {
             "reversed",
             "sorted",
             "str",
+            "tuple",
             "zip"),
         outerEnv.getVariableNames());
     assertEquals(
@@ -177,6 +178,7 @@ public class EnvironmentTest extends EvaluationTestCase {
             "reversed",
             "sorted",
             "str",
+            "tuple",
             "zip"),
         innerEnv.getVariableNames());
   }
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java b/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java
index a001f3ffff..674241d4aa 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/MethodLibraryTest.java
@@ -1845,4 +1845,13 @@ public class MethodLibraryTest extends EvaluationTestCase {
         .testIfErrorContains("abc", "fail('abc')")
         .testIfErrorContains("18", "fail(18)");
   }
+
+  @Test
+  public void testTupleCoercion() throws Exception {
+    new BothModesTest()
+        .testStatement("tuple([1, 2]) == (1, 2)", true)
+        .testStatement("tuple(set([1, 2])) == (1, 2)", true)
+        // Depends on current implementation of dict
+        .testStatement("tuple({1: 'foo', 2: 'bar'}) == (1, 2)", true);
+  }
 }