Introduce --incompatible_load_argument_is_label (1st argument of load must be a label).

RELNOTES:
  First argument of 'load' should be a label. Path syntax is deprecated
  (label should start with '//' or ':').
PiperOrigin-RevId: 158971314

3 files changed, 36 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
index e13074c0c5..fb30f03c0e 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
@@ -60,6 +60,16 @@ public final class LoadStatement extends Statement {
 
   @Override
   void doExec(Environment env) throws EvalException, InterruptedException {
+    if (env.getSemantics().incompatibleLoadArgumentIsLabel) {
+      String s = imp.getValue();
+      if (!s.startsWith("//") && !s.startsWith(":")) {
+        throw new EvalException(
+            getLocation(),
+            "First argument of 'load' must be a label and start with either '//' or ':'. "
+                + "Use --incompatibleLoadArgumentIsLabel to temporarily disable this check.");
+      }
+    }
+
     for (Map.Entry<Identifier, String> entry : symbolMap.entrySet()) {
       try {
         Identifier name = entry.getKey();
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemanticsOptions.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemanticsOptions.java
index 3fd24c45fd..9f92cf978d 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemanticsOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemanticsOptions.java
@@ -88,6 +88,16 @@ public class SkylarkSemanticsOptions extends OptionsBase implements Serializable
   public boolean incompatibleBzlDisallowLoadAfterStatement;
 
   @Option(
+    name = "incompatible_load_argument_is_label",
+    defaultValue = "false",
+    category = "incompatible changes",
+    help =
+        "If set to true, the first argument of 'load' statements is a label (not a path). "
+            + "It must start with '//' or ':'."
+  )
+  public boolean incompatibleLoadArgumentIsLabel;
+
+  @Option(
     name = "incompatible_disallow_toplevel_if_statement",
     defaultValue = "false",
     category = "incompatible changes",
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 81fa580ecb..ba6fd69add 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
@@ -1520,4 +1520,20 @@ public class SkylarkEvaluationTest extends EvaluationTest {
     eval("def foo():", "  a = 10", "  b = [a for a in range(3)]", "  return a", "x = foo()");
     assertThat(lookup("x")).isEqualTo(2);
   }
+
+  @Test
+  public void testLoadStatementWithAbsolutePath() throws Exception {
+    env = newEnvironmentWithSkylarkOptions("--incompatible_load_argument_is_label");
+    checkEvalErrorContains(
+        "First argument of 'load' must be a label and start with either '//' or ':'",
+        "load('/tmp/foo', 'arg')");
+  }
+
+  @Test
+  public void testLoadStatementWithRelativePath() throws Exception {
+    env = newEnvironmentWithSkylarkOptions("--incompatible_load_argument_is_label");
+    checkEvalErrorContains(
+        "First argument of 'load' must be a label and start with either '//' or ':'",
+        "load('foo', 'arg')");
+  }
 }