Remove --incompatible_disable_depset_in_cc_user_flags

Because the flag was flipped by #6383, we can now remove the old code paths.

RELNOTES: None.
PiperOrigin-RevId: 240122125
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java
index 37ee39d..68224d9 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRulesModule.java
@@ -41,6 +41,19 @@
   /** This is where deprecated options go to die. */
   public static class GraveyardOptions extends OptionsBase {
     @Option(
+        name = "incompatible_disable_depset_in_cc_user_flags",
+        defaultValue = "true",
+        documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+        effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
+        metadataTags = {
+          OptionMetadataTag.DEPRECATED,
+          OptionMetadataTag.INCOMPATIBLE_CHANGE,
+          OptionMetadataTag.TRIGGERED_BY_ALL_INCOMPATIBLE_CHANGES
+        },
+        help = "Deprecated no-op.")
+    public boolean disableDepsetInUserFlags;
+
+    @Option(
         name = "incompatible_dont_emit_static_libgcc",
         oldName = "experimental_dont_emit_static_libgcc",
         defaultValue = "true",
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcModule.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcModule.java
index 6f35bc8..6447ad7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcModule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcModule.java
@@ -215,7 +215,7 @@
         /* dwoFile= */ null,
         /* ltoIndexingFile= */ null,
         /* includes= */ ImmutableList.of(),
-        userFlagsToIterable(ccToolchainProvider.getCppConfiguration(), userCompileFlags),
+        userFlagsToIterable(userCompileFlags),
         /* cppModuleMap= */ null,
         usePic,
         /* fakeOutputFile= */ null,
@@ -260,7 +260,7 @@
         featureConfiguration,
         useTestOnlyFlags,
         /* isLtoIndexing= */ false,
-        userFlagsToIterable(ccToolchainProvider.getCppConfiguration(), userLinkFlags),
+        userFlagsToIterable(userLinkFlags),
         /* interfaceLibraryBuilder= */ null,
         /* interfaceLibraryOutput= */ null,
         /* ltoOutputRootPrefix= */ null,
@@ -311,26 +311,14 @@
     }
   }
 
-  /**
-   * Converts an object that represents user flags and can be either SkylarkNestedSet , SkylarkList,
-   * or None into Iterable.
-   */
-  protected Iterable<String> userFlagsToIterable(CppConfiguration cppConfiguration, Object o)
-      throws EvalException {
-    if (o instanceof SkylarkNestedSet) {
-      if (cppConfiguration.disableDepsetInUserFlags()) {
-        throw new EvalException(
-            Location.BUILTIN,
-            "Passing depset into user flags is deprecated (see "
-                + "--incompatible_disable_depset_in_cc_user_flags), use list instead.");
-      }
-      return asStringNestedSet(o);
-    } else if (o instanceof SkylarkList) {
+  /** Converts an object that represents user flags as either SkylarkList or None into Iterable. */
+  protected Iterable<String> userFlagsToIterable(Object o) throws EvalException {
+    if (o instanceof SkylarkList) {
       return asStringImmutableList(o);
     } else if (o instanceof NoneType) {
       return ImmutableList.of();
     } else {
-      throw new EvalException(Location.BUILTIN, "Only depset and list is allowed.");
+      throw new EvalException(Location.BUILTIN, "Only list is allowed.");
     }
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index 221949f..8548c65 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -560,10 +560,6 @@
         + "migration instructions).";
   }
 
-  public boolean disableDepsetInUserFlags() {
-    return cppOptions.disableDepsetInUserFlags;
-  }
-
   public boolean removeCpuCompilerCcToolchainAttributes() {
     return cppOptions.removeCpuCompilerCcToolchainAttributes;
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
index fdadbce..30db4c4 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
@@ -808,21 +808,6 @@
   public boolean experimentalIncludesAttributeSubpackageTraversal;
 
   @Option(
-      name = "incompatible_disable_depset_in_cc_user_flags",
-      defaultValue = "true",
-      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
-      effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
-      metadataTags = {
-        OptionMetadataTag.INCOMPATIBLE_CHANGE,
-        OptionMetadataTag.TRIGGERED_BY_ALL_INCOMPATIBLE_CHANGES
-      },
-      help =
-          "If true, C++ toolchain Starlark API will not accept depset in `user_compile_flags` "
-              + "param of `create_compile_variables`, and in `user_link_flags` of "
-              + "`create_link_variables`. Use list instead.")
-  public boolean disableDepsetInUserFlags;
-
-  @Option(
       name = "experimental_do_not_use_cpu_transformer",
       defaultValue = "false",
       documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
@@ -914,7 +899,6 @@
 
     host.doNotUseCpuTransformer = doNotUseCpuTransformer;
     host.disableGenruleCcToolchainDependency = disableGenruleCcToolchainDependency;
-    host.disableDepsetInUserFlags = disableDepsetInUserFlags;
     host.disableExpandIfAllAvailableInFlagSet = disableExpandIfAllAvailableInFlagSet;
     host.disableLegacyCcProvider = disableLegacyCcProvider;
     host.removeCpuCompilerCcToolchainAttributes = removeCpuCompilerCcToolchainAttributes;
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java
index 8e82d72..64d9ab1 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/cpp/CcModuleApi.java
@@ -261,9 +261,7 @@
             noneable = true),
         @Param(
             name = "user_compile_flags",
-            doc =
-                "List of additional compilation flags (copts). Passing depset is deprecated and "
-                    + "will be removed by --incompatible_disable_depset_in_cc_user_flags flag.",
+            doc = "List of additional compilation flags (copts).",
             positional = false,
             named = true,
             defaultValue = "None",
@@ -271,7 +269,6 @@
             allowedTypes = {
               @ParamType(type = NoneType.class),
               @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class)
             }),
         @Param(
             name = "include_directories",
@@ -387,17 +384,14 @@
             }),
         @Param(
             name = "user_link_flags",
-            doc =
-                "List of additional link flags (linkopts). Passing depset is deprecated and "
-                    + "will be removed by --incompatible_disable_depset_in_cc_user_flags flag.",
+            doc = "List of additional link flags (linkopts).",
             positional = false,
             named = true,
             defaultValue = "None",
             noneable = true,
             allowedTypes = {
               @ParamType(type = NoneType.class),
-              @ParamType(type = SkylarkList.class),
-              @ParamType(type = SkylarkNestedSet.class)
+              @ParamType(type = SkylarkList.class)
             }),
         @Param(
             name = "output_file",
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java
index 5b76f1d..c90dc07 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java
@@ -615,20 +615,6 @@
 
   @Test
   public void testUserCompileFlags() throws Exception {
-    useConfiguration("--noincompatible_disable_depset_in_cc_user_flags");
-    assertThat(
-            commandLineForVariables(
-                CppActionNames.CPP_COMPILE,
-                "cc_common.create_compile_variables(",
-                "feature_configuration = feature_configuration,",
-                "cc_toolchain = toolchain,",
-                "user_compile_flags = depset(['-foo'])",
-                ")"))
-        .contains("-foo");
-  }
-
-  @Test
-  public void testUserCompileFlagsAsList() throws Exception {
     assertThat(
             commandLineForVariables(
                 CppActionNames.CPP_COMPILE,
@@ -641,22 +627,6 @@
   }
 
   @Test
-  public void testUserCompileFlagsAsDepsetWhenDisabled() throws Exception {
-    useConfiguration("--incompatible_disable_depset_in_cc_user_flags");
-    reporter.removeHandler(failFastHandler);
-    assertThat(
-            commandLineForVariables(
-                CppActionNames.CPP_COMPILE,
-                "cc_common.create_compile_variables(",
-                "feature_configuration = feature_configuration,",
-                "cc_toolchain = toolchain,",
-                "user_compile_flags = depset(['-foo'])",
-                ")"))
-        .isNull();
-    assertContainsEvent("Passing depset into user flags is deprecated");
-  }
-
-  @Test
   public void testEmptyLinkVariables() throws Exception {
     assertThat(
             commandLineForVariables(
@@ -728,20 +698,6 @@
 
   @Test
   public void testUserLinkFlagsLinkVariables() throws Exception {
-    useConfiguration("--noincompatible_disable_depset_in_cc_user_flags");
-    assertThat(
-            commandLineForVariables(
-                CppActionNames.CPP_LINK_EXECUTABLE,
-                "cc_common.create_link_variables(",
-                "feature_configuration = feature_configuration,",
-                "cc_toolchain = toolchain,",
-                "user_link_flags = depset([ '-avocado' ]),",
-                ")"))
-        .contains("-avocado");
-  }
-
-  @Test
-  public void testUserLinkFlagsLinkVariablesAsList() throws Exception {
     assertThat(
             commandLineForVariables(
                 CppActionNames.CPP_LINK_EXECUTABLE,
@@ -754,22 +710,6 @@
   }
 
   @Test
-  public void testUserLinkFlagsLinkVariablesAsDepsetWhenDisabled() throws Exception {
-    useConfiguration("--incompatible_disable_depset_in_cc_user_flags");
-    reporter.removeHandler(failFastHandler);
-    assertThat(
-            commandLineForVariables(
-                CppActionNames.CPP_LINK_EXECUTABLE,
-                "cc_common.create_link_variables(",
-                "feature_configuration = feature_configuration,",
-                "cc_toolchain = toolchain,",
-                "user_link_flags = depset([ '-avocado' ]),",
-                ")"))
-        .isNull();
-    assertContainsEvent("Passing depset into user flags is deprecated");
-  }
-
-  @Test
   public void testIfsoRelatedVariablesAreNotExposed() throws Exception {
     AnalysisMock.get()
         .ccSupport()