Remove flag `--incompatible_string_is_not_iterable`

https://github.com/bazelbuild/bazel/issues/5830

RELNOTES: None.
PiperOrigin-RevId: 234784611

src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java b/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
index 06f3762..18fb41d 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/SkylarkSemanticsConsistencyTest.java
@@ -158,7 +158,6 @@
         "--incompatible_remove_native_maven_jar=" + rand.nextBoolean(),
         "--incompatible_require_feature_configuration_for_pic=" + rand.nextBoolean(),
         "--incompatible_strict_argument_ordering=" + rand.nextBoolean(),
-        "--incompatible_string_is_not_iterable=" + rand.nextBoolean(),
         "--incompatible_use_toolchain_providers_in_java_common=" + rand.nextBoolean(),
         "--internal_skylark_flag_test_canary=" + rand.nextBoolean());
   }
@@ -206,7 +205,6 @@
         .incompatibleRemoveNativeMavenJar(rand.nextBoolean())
         .incompatibleRequireFeatureConfigurationForPic(rand.nextBoolean())
         .incompatibleStricArgumentOrdering(rand.nextBoolean())
-        .incompatibleStringIsNotIterable(rand.nextBoolean())
         .incompatibleUseToolchainProvidersInJavaCommon(rand.nextBoolean())
         .internalSkylarkFlagTestCanary(rand.nextBoolean())
         .build();
@@ -219,4 +217,3 @@
     return parser.getOptions(StarlarkSemanticsOptions.class);
   }
 }
-

src/test/java/com/google/devtools/build/lib/syntax/EvalUtilsTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/syntax/EvalUtilsTest.java b/src/test/java/com/google/devtools/build/lib/syntax/EvalUtilsTest.java
index eec32d1..2701457 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/EvalUtilsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/EvalUtilsTest.java
@@ -47,16 +47,6 @@
     return SkylarkDict.of(env, 1, 1, 2, 2);
   }
 
-  @Test
-  public void testEmptyStringToIterable() throws Exception {
-    assertThat(EvalUtils.toIterable("", null, null)).isEmpty();
-  }
-
-  @Test
-  public void testStringToIterable() throws Exception {
-    assertThat(EvalUtils.toIterable("abc", null, null)).hasSize(3);
-  }
-
   /** MockClassA */
   @SkylarkModule(name = "MockClassA", doc = "MockClassA")
   public static class MockClassA {

src/test/java/com/google/devtools/build/lib/syntax/EvaluationTest.java

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 05cbd17..6ee8f87 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
@@ -507,15 +507,8 @@
   }
 
   @Test
-  public void testListComprehensionOnString() throws Exception {
-    newTest("--incompatible_string_is_not_iterable=false")
-        .testExactOrder("[x for x in 'abc']", "a", "b", "c");
-  }
-
-  @Test
   public void testListComprehensionOnStringIsForbidden() throws Exception {
-    newTest("--incompatible_string_is_not_iterable=true")
-        .testIfErrorContains("type 'string' is not iterable", "[x for x in 'abc']");
+    newTest().testIfErrorContains("type 'string' is not iterable", "[x for x in 'abc']");
   }
 
   @Test

src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java

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 3d89729..2ef84a6 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
@@ -688,19 +688,6 @@
   }
 
   @Test
-  public void testForOnString() throws Exception {
-    new SkylarkTest("--incompatible_string_is_not_iterable=false")
-        .setUp(
-            "def foo():",
-            "  s = []",
-            "  for i in 'abc':",
-            "    s = s + [i]",
-            "  return s",
-            "s = foo()")
-        .testExactOrder("s", "a", "b", "c");
-  }
-
-  @Test
   public void testForAssignmentList() throws Exception {
     new SkylarkTest().setUp("def foo():",
         "  d = ['a', 'b', 'c']",
@@ -841,6 +828,14 @@
   }
 
   @Test
+  public void testForStringNotIterable() throws Exception {
+    new SkylarkTest()
+        .update("mock", new Mock())
+        .testIfErrorContains(
+            "type 'string' is not iterable", "def func():", "  for i in 'abc': a = i", "func()\n");
+  }
+
+  @Test
   public void testForOnDictionary() throws Exception {
     new SkylarkTest().setUp("def foo():",
         "  d = {1: 'a', 2: 'b', 3: 'c'}",