Make SelectorList.toString() user-friendly.

This also guarantees consistency between toString()
calls to lib.syntax.SelectorList and
lib.packages.BuildType.SelectorList.

PiperOrigin-RevId: 157617509

3 files changed, 48 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/packages/BuildType.java b/src/main/java/com/google/devtools/build/lib/packages/BuildType.java
index 5df9d83625..6a32c68d57 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/BuildType.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/BuildType.java
@@ -23,6 +23,7 @@ import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
 import com.google.devtools.build.lib.packages.License.DistributionType;
 import com.google.devtools.build.lib.packages.License.LicenseParsingException;
+import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.Printer;
 import com.google.devtools.build.lib.syntax.Runtime;
 import com.google.devtools.build.lib.syntax.SelectorValue;
@@ -30,7 +31,6 @@ import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.syntax.Type.ConversionException;
 import com.google.devtools.build.lib.syntax.Type.DictType;
 import com.google.devtools.build.lib.syntax.Type.LabelClass;
-import com.google.devtools.build.lib.syntax.Type.LabelVisitor;
 import com.google.devtools.build.lib.syntax.Type.ListType;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -520,6 +520,21 @@ public final class BuildType {
       }
       return keys.build();
     }
+
+    @Override
+    public String toString() {
+      // Convert to a lib.syntax.SelectorList to guarantee consistency with callers that serialize
+      // directly on that type.
+      List<SelectorValue> selectorValueList = new ArrayList<>();
+      for (Selector<T> element : elements) {
+        selectorValueList.add(new SelectorValue(element.getEntries(), element.getNoMatchError()));
+      }
+      try {
+        return com.google.devtools.build.lib.syntax.SelectorList.of(selectorValueList).toString();
+      } catch (EvalException e) {
+        throw new IllegalStateException("this list should have been validated on creation");
+      }
+    }
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java b/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java
index 0feb423453..5e72aedcd5 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java
@@ -17,8 +17,10 @@ import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
+import com.google.devtools.build.lib.util.Preconditions;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 
 /**
@@ -97,6 +99,19 @@ public final class SelectorList implements SkylarkValue {
     return new SelectorList(type1, builder.build());
   }
 
+  /**
+   * Creates a list consisting of the given selects.
+   */
+  public static SelectorList of(List<SelectorValue> selectors) throws EvalException {
+    Preconditions.checkArgument(!selectors.isEmpty());
+    Iterator<SelectorValue> it = selectors.iterator();
+    SelectorList list = SelectorList.of(it.next());
+    while (it.hasNext()) {
+      list = SelectorList.concat(null, list, it.next());
+    }
+    return list;
+  }
+
   // TODO(bazel-team): match on the List interface, not the actual implementation. For now,
   // we verify this is the right class through test coverage.
   private static final Class<?> NATIVE_LIST_TYPE = ArrayList.class;
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java
index 8eeeb23bb4..c2010d571a 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java
@@ -495,6 +495,23 @@ public class SkylarkRuleContextTest extends SkylarkTestCase {
   }
 
   @Test
+  public void existingRuleWithSelect() throws Exception {
+    scratch.file(
+        "test/existing_rule.bzl",
+        "def macro():",
+        "  s = select({'//foo': ['//bar']})",
+        "  native.cc_library(name = 'x', srcs = s)",
+        "  print(native.existing_rule('x')['srcs'])");
+    scratch.file(
+        "test/BUILD",
+        "load('//test:existing_rule.bzl', 'macro')",
+        "macro()",
+        "cc_library(name = 'a', srcs = [])");
+    getConfiguredTarget("//test:a");
+    assertContainsEvent("selector({\"//foo:foo\": [\"//bar:bar\"]})");
+  }
+
+  @Test
   public void testGetRule() throws Exception {
     scratch.file("test/skylark/BUILD");
     scratch.file(