Remove the `direct_host_only` required fragments setting.

PiperOrigin-RevId: 400016860
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/CoreOptions.java b/src/main/java/com/google/devtools/build/lib/analysis/config/CoreOptions.java
index ae769d7..4ec09ca 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/CoreOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/CoreOptions.java
@@ -731,16 +731,16 @@
       help =
           "INTERNAL BLAZE DEVELOPER FEATURE: If \"direct\", all configured targets expose "
               + "RequiredConfigFragmentsProvider with the configuration fragments they directly "
-              + "require (use \"direct_host_only\" to limit to targets in the host configuration). "
+              + "require. "
               + "If \"transitive\", they do the same but also include the fragments their "
               + "transitive dependencies require. If \"off\", the provider is omitted. "
               + ""
               + "If not \"off\", this also populates config_setting's "
-              + " ConfigMatchingProvider.requiredFragmentOptions with the fragment options "
-              + " the config_setting requires."
+              + "ConfigMatchingProvider.requiredFragmentOptions with the fragment options the "
+              + "config_setting requires."
               + ""
               + "Be careful using this feature: it adds memory to every configured target in the "
-              + "build")
+              + "build.")
   public IncludeConfigFragmentsEnum includeRequiredConfigFragmentsProvider;
 
   @Option(
@@ -811,11 +811,6 @@
      * information and don't need the extra memory hit over every configured target.
      */
     OFF,
-    /**
-     * Provide the fragments required <em>directly</em> by this rule if it is being analyzed in the
-     * host configuration.
-     */
-    DIRECT_HOST_ONLY,
     /** Provide the fragments required <em>directly</em> by this rule. */
     DIRECT,
     /** Provide the fragments required by this rule and its transitive dependencies. */
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/RequiredFragmentsUtil.java b/src/main/java/com/google/devtools/build/lib/analysis/config/RequiredFragmentsUtil.java
index 6361a26..ee550f0 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/RequiredFragmentsUtil.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/RequiredFragmentsUtil.java
@@ -14,6 +14,8 @@
 
 package com.google.devtools.build.lib.analysis.config;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import com.google.common.collect.Collections2;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -282,16 +284,7 @@
   private static boolean requiredFragmentsEnabled(BuildConfiguration config) {
     IncludeConfigFragmentsEnum setting =
         config.getOptions().get(CoreOptions.class).includeRequiredConfigFragmentsProvider;
-    switch (setting) {
-      case OFF:
-        return false;
-      case DIRECT_HOST_ONLY:
-        return config.isHostConfiguration();
-      case DIRECT:
-      case TRANSITIVE:
-        return true;
-    }
-    throw new AssertionError(setting);
+    return checkNotNull(setting) != IncludeConfigFragmentsEnum.OFF;
   }
 
   private RequiredFragmentsUtil() {}
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/RequiredConfigFragmentsTest.java b/src/test/java/com/google/devtools/build/lib/analysis/RequiredConfigFragmentsTest.java
index f1898f5..6cbdf8b 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/RequiredConfigFragmentsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/RequiredConfigFragmentsTest.java
@@ -78,25 +78,6 @@
   }
 
   @Test
-  public void provideDirectHostOnlyRequiredFragmentsMode() throws Exception {
-    useConfiguration("--include_config_fragments_provider=direct_host_only");
-    scratch.file(
-        "a/BUILD",
-        "py_library(name = 'pylib', srcs = ['pylib.py'])",
-        "cc_library(name = 'cclib', srcs = ['cclb.cc'], data = [':pylib'])");
-
-    RequiredConfigFragmentsProvider targetConfigProvider =
-        getConfiguredTarget("//a:cclib").getProvider(RequiredConfigFragmentsProvider.class);
-    RequiredConfigFragmentsProvider hostConfigProvider =
-        getHostConfiguredTarget("//a:cclib").getProvider(RequiredConfigFragmentsProvider.class);
-
-    assertThat(targetConfigProvider).isNull();
-    assertThat(hostConfigProvider).isNotNull();
-    assertThat(hostConfigProvider.getFragmentClasses()).contains(CppConfiguration.class);
-    assertThat(hostConfigProvider.getFragmentClasses()).doesNotContain(PythonConfiguration.class);
-  }
-
-  @Test
   public void requiresMakeVariablesSuppliedByDefine() throws Exception {
     useConfiguration("--include_config_fragments_provider=direct", "--define", "myvar=myval");
     scratch.file(
diff --git a/src/test/shell/integration/configured_query_test.sh b/src/test/shell/integration/configured_query_test.sh
index bc5c48e..040ca56 100755
--- a/src/test/shell/integration/configured_query_test.sh
+++ b/src/test/shell/integration/configured_query_test.sh
@@ -450,32 +450,6 @@
   assert_not_contains "//$pkg:cclib_with_py_dep .*PythonConfiguration" output
 }
 
-function test_show_direct_host_only_config_fragments() {
-  local -r pkg=$FUNCNAME
-  mkdir -p $pkg
-  cat > $pkg/BUILD <<'EOF'
-genrule(
-    name = "gen",
-    outs = ["gen.out"],
-    cmd = "$(location :tool) > $@",
-    tools = [":tool"],
-)
-
-genrule(
-    name = "tool",
-    outs = ["tool.sh"],
-    cmd = 'echo "echo built by TOOL" > $@',
-)
-EOF
-
-  bazel cquery "deps(//$pkg:gen)" --show_config_fragments=direct_host_only \
-    > output 2>"$TEST_log" || fail "Expected success"
-
-  assert_contains "//$pkg:gen" output
-  assert_not_contains "//$pkg:gen .*CoreOptions" output
-  assert_contains "//$pkg:tool .*CoreOptions" output
-}
-
 function test_show_direct_config_fragments_select() {
   local -r pkg=$FUNCNAME
   mkdir -p $pkg