Print singleton tuples with a comma

Like python, print singleton tuples with a terminating comma before the closing
parenthesis, so you can read them back as tuples.

Also, have toString() call the pretty-printer for Skylark lists and tuples.

--
MOS_MIGRATED_REVID=88831764

4 files changed, 25 insertions, 11 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java b/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java
index c03a9ff4a4..4c5c23d2d1 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/EvalUtils.java
@@ -298,7 +298,7 @@ public abstract class EvalUtils {
 
     } else if (o instanceof Map<?, ?>) {
       Map<?, ?> dict = (Map<?, ?>) o;
-      printList(dict.entrySet(), "{", ", ", "}", buffer);
+      printList(dict.entrySet(), "{", ", ", "}", null, buffer);
 
     } else if (o instanceof Map.Entry<?, ?>) {
       Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
@@ -309,7 +309,7 @@ public abstract class EvalUtils {
     } else if (o instanceof SkylarkNestedSet) {
       SkylarkNestedSet set = (SkylarkNestedSet) o;
       buffer.append("set(");
-      printList(set, "[", ", ", "]", buffer);
+      printList(set, "[", ", ", "]", null, buffer);
       Order order = set.getOrder();
       if (order != Order.STABLE_ORDER) {
         buffer.append(", order = \"" + SkylarkNestedSet.orderString(order) + "\"");
@@ -343,13 +343,21 @@ public abstract class EvalUtils {
   }
 
   private static void printList(Iterable<?> list,
-      String before, String separator, String after, Appendable buffer) throws IOException {
-    String sep = "";
+      String before, String separator, String after, String singletonTerminator, Appendable buffer)
+      throws IOException {
+    boolean printSeparator = false; // don't print the separator before the first element
+    int len = 0;
     buffer.append(before);
     for (Object o : list) {
-      buffer.append(sep);
+      if (printSeparator) {
+        buffer.append(separator);
+      }
       prettyPrintValue(o, buffer);
-      sep = separator;
+      printSeparator = true;
+      len++;
+    }
+    if (singletonTerminator != null && len == 1) {
+      buffer.append(singletonTerminator);
     }
     buffer.append(after);
   }
@@ -357,9 +365,9 @@ public abstract class EvalUtils {
   private static void printList(Iterable<?> list, boolean isTuple, Appendable buffer)
       throws IOException {
     if (isTuple) {
-      printList(list, "(", ", ", ")", buffer);
+      printList(list, "(", ", ", ")", ",", buffer);
     } else {
-      printList(list, "[", ", ", "]", buffer);
+      printList(list, "[", ", ", "]", null, buffer);
     }
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkList.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkList.java
index 305ccbeacd..983ebb484f 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkList.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkList.java
@@ -80,7 +80,7 @@ public abstract class SkylarkList implements Iterable<Object> {
 
   @Override
   public String toString() {
-    return toList().toString();
+    return EvalUtils.prettyPrintValue(this);
   }
 
   // TODO(bazel-team): we should be very careful using this method. Check and remove
@@ -178,7 +178,7 @@ public abstract class SkylarkList implements Iterable<Object> {
 
     @Override
     public String toString() {
-      return list.toString();
+      return EvalUtils.prettyPrintValue(this);
     }
 
     @Override
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/EvaluationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/EvaluationTest.java
index 3fd5508922..b2bfaecf3c 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/EvaluationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/EvaluationTest.java
@@ -427,7 +427,7 @@ public class EvaluationTest extends AbstractEvaluationTestCase {
   public void testListComprehensionOnDictionaryCompositeExpression() throws Exception {
     exec(parseFile("d = {1:'a',2:'b'}\n"
                   + "l = [d[x] for x in d]"), env);
-    assertEquals("[a, b]", env.lookup("l").toString());
+    assertEquals("[\"a\", \"b\"]", EvalUtils.prettyPrintValue(env.lookup("l")));
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
index 633744cfea..65996d878b 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
@@ -816,6 +816,12 @@ public class SkylarkEvaluationTest extends EvaluationTest {
     assertEquals("a1", env.lookup("v"));
   }
 
+  @Test
+  public void testSingletonTuple() throws Exception {
+    exec(parseFileForSkylark("v = (1,)"), env);
+    assertEquals("(1,)", env.lookup("v").toString());
+  }
+
   @SuppressWarnings("unchecked")
   @Test
   public void testDirFindsClassObjectFields() throws Exception {