bzlmod: Improve setBzlFile function in RepoSpec.java

RELNOTES: None
PiperOrigin-RevId: 381468614
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpec.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpec.java
index 6bde0a7..844168e 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpec.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpec.java
@@ -41,7 +41,7 @@
   /** The builder for {@link RepoSpec} */
   @AutoValue.Builder
   public abstract static class Builder {
-    public abstract Builder setBzlFile(Optional<String> bzlFile);
+    public abstract Builder setBzlFile(String bzlFile);
 
     public abstract Builder setRuleClassName(String name);
 
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpecTest.java b/src/test/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpecTest.java
index 99c06d6..754f65d 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpecTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/bzlmod/RepoSpecTest.java
@@ -18,7 +18,6 @@
 import static com.google.common.truth.Truth8.assertThat;
 
 import com.google.common.collect.ImmutableMap;
-import java.util.Optional;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -44,7 +43,7 @@
   public void starlarkRepoSpecTest() {
     RepoSpec repoSpec =
         RepoSpec.builder()
-            .setBzlFile(Optional.of("//pkg:repo.bzl"))
+            .setBzlFile("//pkg:repo.bzl")
             .setRuleClassName("my_repo")
             .setAttributes(ImmutableMap.of("attr1", "foo", "attr2", "bar"))
             .build();