New config option testbuildonly

BUILD.bazel

@@ -135,6 +135,7 @@ go_config(
         "//go/private:is_strip_sometimes_fastbuild": True,
         "//conditions:default": False,
     }),
+    testbuildonly = "//go/config:testbuildonly",
     visibility = ["//visibility:public"],
 )
 

go/config/BUILD.bazel

@@ -79,3 +79,9 @@ string_list_flag(
     build_setting_default = [],
     visibility = ["//visibility:public"],
 )
+
+bool_flag(
+    name = "testbuildonly",
+    build_setting_default = False,
+    visibility = ["//visibility:public"],
+)

go/private/actions/link.bzl

@@ -75,6 +75,22 @@ def emit_link(
     if executable == None:
         fail("executable is a required parameter")
 
+    if go.mode.testbuildonly and executable.basename.endswith("_test"):
+        inputs_transitive = [
+            archive.libs, archive.cgo_deps,
+            as_set(go.crosstool),
+            as_set(go.sdk.tools),
+            as_set(go.stdlib.libs),
+        ]
+        go.actions.run(
+            inputs = depset(direct = [go.sdk.package_list], transitive = inputs_transitive),
+            outputs = [executable],
+            mnemonic = "Touch",
+            executable = "/usr/bin/touch",
+            arguments = [executable.path],
+        )
+        return
+
     # Exclude -lstdc++ from link options. We don't want to link against it
     # unless we actually have some C++ code. _cgo_codegen will include it
     # in archives via CGO_LDFLAGS if it's needed.

go/private/context.bzl

@@ -836,6 +836,7 @@ def _go_config_impl(ctx):
         cover_format = ctx.attr.cover_format[BuildSettingInfo].value,
         gc_goopts = ctx.attr.gc_goopts[BuildSettingInfo].value,
         amd64 = ctx.attr.amd64,
+        testbuildonly = ctx.attr.testbuildonly[BuildSettingInfo].value,
     )]
 
 go_config = rule(
@@ -884,6 +885,10 @@ go_config = rule(
             providers = [BuildSettingInfo],
         ),
         "amd64": attr.string(),
+        "testbuildonly": attr.label(
+            mandatory = True,
+            providers = [BuildSettingInfo],
+        ),
     },
     provides = [GoConfigInfo],
     doc = """Collects information about build settings in the current

go/private/mode.bzl

@@ -52,6 +52,8 @@ def mode_string(mode):
         result.append("debug")
     if mode.strip:
         result.append("stripped")
+    if mode.testbuildonly:
+        result.append("testbuildonly")
     if not result or not mode.link == LINKMODE_NORMAL:
         result.append(mode.link)
     if mode.gc_goopts:
@@ -93,6 +95,7 @@ def get_mode(ctx, go_toolchain, cgo_context_info, go_config_info):
     goos = go_toolchain.default_goos if getattr(ctx.attr, "goos", "auto") == "auto" else ctx.attr.goos
     goarch = go_toolchain.default_goarch if getattr(ctx.attr, "goarch", "auto") == "auto" else ctx.attr.goarch
     gc_goopts = go_config_info.gc_goopts if go_config_info else []
+    testbuildonly = go_config_info.testbuildonly if go_config_info else False
 
     # TODO(jayconrod): check for more invalid and contradictory settings.
     if pure and race:
@@ -130,6 +133,7 @@ def get_mode(ctx, go_toolchain, cgo_context_info, go_config_info):
         cover_format = cover_format,
         amd64 = amd64,
         gc_goopts = gc_goopts,
+        testbuildonly = testbuildonly,
     )
 
 def installsuffix(mode):

go/private/rules/transition.bzl

@@ -177,6 +177,7 @@ _common_reset_transition_dict = dict({
     "//go/config:debug": False,
     "//go/config:linkmode": LINKMODE_NORMAL,
     "//go/config:tags": [],
+    "//go/config:testbuildonly": False,
 }, **{setting: "" for setting in _SETTING_KEY_TO_ORIGINAL_SETTING_KEY.values()})
 
 _reset_transition_dict = dict(_common_reset_transition_dict, **{