[build-script] Make is_build_script_impl_product() a pure method and get rid of default Yes answer.

utils/swift_build_support/swift_build_support/products/cmark.py

@@ -14,4 +14,10 @@
 
 
 class CMark(product.Product):
-    pass
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True

utils/swift_build_support/swift_build_support/products/foundation.py

@@ -14,6 +14,14 @@
 
 
 class Foundation(product.Product):
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True
+
     @classmethod
     def product_source_name(cls):
         """product_source_name() -> str

utils/swift_build_support/swift_build_support/products/libcxx.py

@@ -14,4 +14,10 @@
 
 
 class LibCXX(product.Product):
-    pass
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True

utils/swift_build_support/swift_build_support/products/libdispatch.py

@@ -14,6 +14,14 @@
 
 
 class LibDispatch(product.Product):
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True
+
     @classmethod
     def product_source_name(cls):
         """product_source_name() -> str

utils/swift_build_support/swift_build_support/products/libicu.py

@@ -14,6 +14,14 @@
 
 
 class LibICU(product.Product):
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True
+
     @classmethod
     def product_source_name(cls):
         """product_source_name() -> str

utils/swift_build_support/swift_build_support/products/llbuild.py

@@ -14,4 +14,10 @@
 
 
 class LLBuild(product.Product):
-    pass
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True

utils/swift_build_support/swift_build_support/products/lldb.py

@@ -14,4 +14,10 @@
 
 
 class LLDB(product.Product):
-    pass
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True

utils/swift_build_support/swift_build_support/products/llvm.py

@@ -34,6 +34,14 @@ def __init__(self, args, toolchain, source_dir, build_dir):
         # Add the cmake options for compiler version information.
         self.cmake_options.extend(self._version_flags)
 
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True
+
     @property
     def _compiler_vendor_flags(self):
         if self.args.compiler_vendor == "none":

utils/swift_build_support/swift_build_support/products/product.py

@@ -55,7 +55,7 @@ def is_build_script_impl_product(cls):
 
         Whether this product is produced by build-script-impl.
         """
-        return True
+        raise NotImplementedError
 
     @classmethod
     def is_swiftpm_unified_build_product(cls):

utils/swift_build_support/swift_build_support/products/swift.py

@@ -45,6 +45,14 @@ def __init__(self, args, toolchain, source_dir, build_dir):
         self.cmake_options.extend(
             self._enable_experimental_differentiable_programming)
 
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True
+
     @property
     def _runtime_sanitizer_flags(self):
         sanitizer_list = []

utils/swift_build_support/swift_build_support/products/xctest.py

@@ -14,6 +14,14 @@
 
 
 class XCTest(product.Product):
+    @classmethod
+    def is_build_script_impl_product(cls):
+        """is_build_script_impl_product -> bool
+
+        Whether this product is produced by build-script-impl.
+        """
+        return True
+
     @classmethod
     def product_source_name(cls):
         """product_source_name() -> str