go-marshal tests should respect build tags.

Previously, the go-marshal-generated tests did not respect build
tags. This can cause the test to unbuildable under some build
configurations, as the original types the tests refer to may not be
defined.

This CL copies the build tags from the input files to the test,
similar to the generated library; however test packages have an
additional constraint. A test package cannot be totally empty
(i.e. have no test/example/benchmark defined), otherwise the go
compiler returns an error. To ensure the generated test package always
contains a testable entity under all build configurations, we now emit
an extra test file with no build tags that contains a single no-op
example.

PiperOrigin-RevId: 334496821

1 files changed, 6 insertions, 3 deletions

diff --git a/tools/go_marshal/defs.bzl b/tools/go_marshal/defs.bzl
index ba98f3599..f44f83eab 100644
--- a/tools/go_marshal/defs.bzl
+++ b/tools/go_marshal/defs.bzl
@@ -4,11 +4,13 @@ def _go_marshal_impl(ctx):
     """Execute the go_marshal tool."""
     output = ctx.outputs.lib
     output_test = ctx.outputs.test
+    output_test_unconditional = ctx.outputs.test_unconditional
 
     # Run the marshal command.
     args = ["-output=%s" % output.path]
-    args += ["-pkg=%s" % ctx.attr.package]
-    args += ["-output_test=%s" % output_test.path]
+    args.append("-pkg=%s" % ctx.attr.package)
+    args.append("-output_test=%s" % output_test.path)
+    args.append("-output_test_unconditional=%s" % output_test_unconditional.path)
 
     if ctx.attr.debug:
         args += ["-debug"]
@@ -18,7 +20,7 @@ def _go_marshal_impl(ctx):
         args += [f.path for f in src.files.to_list()]
     ctx.actions.run(
         inputs = ctx.files.srcs,
-        outputs = [output, output_test],
+        outputs = [output, output_test, output_test_unconditional],
         mnemonic = "GoMarshal",
         progress_message = "go_marshal: %s" % ctx.label,
         arguments = args,
@@ -48,6 +50,7 @@ go_marshal = rule(
     outputs = {
         "lib": "%{name}_unsafe.go",
         "test": "%{name}_test.go",
+        "test_unconditional": "%{name}_unconditional_test.go",
     },
 )