Automated rollback of commit d3dd9d1.

*** Reason for rollback ***

Breaks lots of tests with "method 'getattr' returns an object of invalid type SingletonSet" error; see b/123520324

*** Original change description ***

Convert MethodLibrary's SkylarkSignature methods to SkylarkCallable

Note that converted parameter @param annotations need legacyNamed = true (and in some places, noneable = True) to retain compatibility with the bugginess of SkylarkSignature.

This facilitates followup to clean up these methods / parameters -- given the refactor, we can enforce some of these parameters are positional-only (subject to an --incompatible flag)

Progress toward #5010

RELNOTES: None.
PiperOrigin-RevId: 231264758

src/main/java/com/google/devtools/build/docgen/ApiExporter.java

@@ -27,7 +27,6 @@
 import com.google.devtools.build.lib.skylarkinterface.SkylarkInterfaceUtils;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.syntax.BaseFunction;
-import com.google.devtools.build.lib.syntax.BuiltinCallable;
 import com.google.devtools.build.lib.syntax.FuncallExpression;
 import com.google.devtools.build.lib.syntax.FunctionSignature;
 import com.google.devtools.build.lib.syntax.MethodDescriptor;
@@ -94,15 +93,6 @@ private static void appendGlobals(Builtins.Builder builtins, Map<String, Object>
       Value.Builder value = Value.newBuilder();
       if (obj instanceof BaseFunction) {
         value = collectFunctionInfo((BaseFunction) obj);
-      } else if (obj instanceof BuiltinCallable) {
-        BuiltinCallable builtinCallable = (BuiltinCallable) obj;
-        MethodDescriptor descriptor =
-            builtinCallable.getMethodDescriptor(SkylarkSemantics.DEFAULT_SEMANTICS);
-        value =
-            collectFunctionInfo(
-                descriptor.getName(),
-                SkylarkSignatureProcessor.getSignatureForCallable(
-                    descriptor.getName(), descriptor, null, null));
       } else {
         value.setName(entry.getKey());
       }

src/main/java/com/google/devtools/build/lib/syntax/BuiltinCallable.java

@@ -42,7 +42,8 @@ public Object call(
       FuncallExpression ast,
       Environment env)
       throws EvalException, InterruptedException {
-    MethodDescriptor methodDescriptor = getMethodDescriptor(env.getSemantics());
+    MethodDescriptor methodDescriptor =
+        FuncallExpression.getMethod(env.getSemantics(), obj.getClass(), methodName);
 
     // TODO(cparsons): Profiling should be done at the MethodDescriptor level.
     try (SilentCloseable c =
@@ -54,10 +55,6 @@ public Object call(
     }
   }
 
-  public MethodDescriptor getMethodDescriptor(SkylarkSemantics semantics) {
-    return FuncallExpression.getMethod(semantics, obj.getClass(), methodName);
-  }
-
   @Override
   public void repr(SkylarkPrinter printer) {
     printer.append("<built-in function " + methodName + ">");

src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java

@@ -647,7 +647,7 @@ private EvalException unexpectedKeywordArgumentException(
         String.format(
             "unexpected keyword%s %s",
             unexpectedKeywords.size() > 1 ? "s" : "",
-            Joiner.on(", ").join(Iterables.transform(unexpectedKeywords, s -> "'" + s + "'"))),
+            Joiner.on(",").join(Iterables.transform(unexpectedKeywords, s -> "'" + s + "'"))),
         method,
         objClass);
   }