Fix cc_shared_library error with hdr-only libraries

cc_libraries with a linker_input with no libraries (either because they
contain only headers or only linkopts) caused errors in cc_shared_libraries
triggered by a check that made sure that a cc_library wasn't linked more than
once into different shared libraries. That check can be ignored in those cases.

Fixes bazelbuild#19920

RELNOTES:none
PiperOrigin-RevId: 578101246
Change-Id: I61ff349411b51ea01314f3782d79b2f540a63856

src/main/starlark/builtins_bzl/common/cc/cc_shared_library.bzl

@@ -454,6 +454,11 @@ def _filter_inputs(
  _add_linker_input_to_dict(linker_input.owner, transitive_exports[owner])
  linker_inputs_count += 1
  elif owner in targets_to_be_linked_statically_map:
+ if not linker_input.libraries:
+ # TODO(bazel-team): semantics.should_create_empty_archive() should be
+ # cleaned up and return False in every case. cc_libraries shouldn't
+ # produce empty archives. For now issue #19920 is only fixed in Bazel.
+ continue
  if owner in link_once_static_libs_map:
  # We are building a dictionary that will allow us to give
  # proper errors for libraries that have been linked multiple

src/main/starlark/tests/builtins_bzl/cc/cc_shared_library/test_cc_shared_library/BUILD.builtin_test

@@ -156,7 +156,7 @@ cc_library(
  "//conditions:default": [],
  }),
  deps = select({
- ":is_bazel": ["qux2"],
+ ":is_bazel": ["qux2", "hdr_only"],
  "//conditions:default": [],
  }) + [
  "bar",
@@ -298,7 +298,7 @@ cc_library(
  deps = [
  "barX",
  ] + select({
- ":is_bazel": ["qux2"],
+ ":is_bazel": ["qux2", "hdr_only"],
  "//conditions:default": [],
  }),
 )
@@ -449,6 +449,17 @@ cc_library(
  srcs = [":private_cc_library.cc"]
 )
 
+genrule(
+ name = "hdr_only_hdr",
+ outs = ["hdr_only_hdr.h"],
+ cmd = "touch $@",
+)
+
+cc_library(
+ name = "hdr_only",
+ hdrs = [":hdr_only_hdr"],
+)
+
 build_failure_test(
  name = "two_dynamic_deps_same_export_in_so_test",
  message = "Two shared libraries in dependencies export the same symbols",