Explicit dependency on executables in proto_library.gni.

third_party/protobuf/proto_library.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Compile a protocol buffer.
 #
 # Protobuf parameters:
 #
 #   proto_in_dir (optional)
 #       Specifies the path relative to the current BUILD.gn file where
@@ skipping 95 matching lines @@
   }
 
   if (defined(invoker.generator_plugin_label)) {
     # Straightforward way to get the name of executable doesn't work because
     # |root_out_dir| and |root_build_dir| may differ in cross-compilation and
     # also Windows executables have .exe at the end.
 
     plugin_host_label = invoker.generator_plugin_label + "($host_toolchain)"
     plugin_path = get_label_info(plugin_host_label, "root_out_dir") + "/" +
                   get_label_info(plugin_host_label, "name")
     if (host_os == "win") {

[sdefresne, 2016/10/18 22:44:54]

This is done multiple time in this file. I would recommend adding this at the
top of the file:

if (host_os == "win") {
  _host_executable_suffix = ".exe"
} else {
  _host_executable_suffix = ""
}

And then, use:

    plugin_path = get_label_info(plugin_host_label, "root_out_dir") + "/" +
                  get_label_info(plugin_host_label, "name") +
                  _host_executable_suffix

[kraynov, 2016/10/19 11:04:59]

Done.

       plugin_path += ".exe"
     }
     generate_with_plugin = true
   } else if (defined(invoker.generator_plugin_script)) {
     plugin_path = invoker.generator_plugin_script
     generate_with_plugin = true
   } else {
     generate_with_plugin = false
   }
 
   if (generate_with_plugin) {
     if (defined(invoker.generator_plugin_suffix)) {
       generator_plugin_suffixes = [
         "${invoker.generator_plugin_suffix}.h",
         "${invoker.generator_plugin_suffix}.cc",
       ]
     } else {
       generator_plugin_suffixes = invoker.generator_plugin_suffixes
     }
-    plugin_path = rebase_path(plugin_path, root_build_dir)
   }
 
   if (defined(invoker.proto_in_dir)) {
     proto_in_dir = invoker.proto_in_dir
     has_nested_dirs = false
     foreach(proto_source, proto_sources) {
       if (get_path_info(proto_source, "dir") != proto_in_dir) {
         has_nested_dirs = true
       }
     }
@@ skipping 62 matching lines @@
   source_set_name = target_name
 
   # Generate protobuf stubs.
   action(action_name) {
     visibility = [ ":$source_set_name" ]
     script = "//tools/protoc_wrapper/protoc_wrapper.py"
     sources = proto_sources
     outputs = get_path_info(protogens, "abspath")
     args = protos
 
-    if (defined(invoker.generator_plugin_script)) {
-      inputs = [
-        invoker.generator_plugin_script,

[kraynov, 2016/10/18 12:35:52]

It's not missing :)
invoker.generator_plugin_script == plugin_path
See line 284 at the right pane.

[sdefresne, 2016/10/18 22:44:54]

Ack.

-      ]
-    }
-    if (defined(invoker.generator_plugin_script_deps)) {
-      inputs += invoker.generator_plugin_script_deps
+    protoc_label = "//third_party/protobuf:protoc($host_toolchain)"
+    protoc_path = get_label_info(protoc_label, "root_out_dir") + "/protoc"

[sdefresne, 2016/10/18 22:44:54]

    protoc_path = get_label_info(protoc_label, "root_out_dir") + "/protoc" +
        _host_executable_suffix

[kraynov, 2016/10/19 11:04:59]

Done.

+    if (host_os == "win") {
+      protoc_path += ".exe"
     }
 
-    protoc_label = "//third_party/protobuf:protoc($host_toolchain)"
-    protoc_out_dir = get_label_info(protoc_label, "root_out_dir")
     args += [
       # Wrapper should never pick a system protoc.
       # Path should be rebased because |root_build_dir| for current toolchain
       # may be different from |root_out_dir| of protoc built on host toolchain.
       "--protoc",
-      "./" + rebase_path(protoc_out_dir, root_build_dir) + "/protoc",
+      rebase_path(protoc_path, root_build_dir),
       "--proto-in-dir",
       rebase_path(proto_in_dir, root_build_dir),
     ]
 
     if (generate_cc) {
       args += [
         "--cc-out-dir",
         rel_cc_out_dir,
       ]
       if (defined(invoker.cc_generator_options)) {
@@ skipping 13 matching lines @@
     if (generate_python) {
       args += [
         "--py-out-dir",
         rel_py_out_dir,
       ]
     }
 
     if (generate_with_plugin) {
       args += [
         "--plugin",
-        plugin_path,
+        rebase_path(plugin_path, root_build_dir),
         "--plugin-out-dir",
         rel_cc_out_dir,
       ]
       if (defined(invoker.generator_plugin_options)) {
         args += [
           "--plugin-options",
           invoker.generator_plugin_options,
         ]
       }
     }
 
+    # System protoc is not used so it's necessary to build a chromium one.
+    inputs = [
+      protoc_path,
+    ]
     deps = [
-      # System protoc is not used so it's necessary to build a chromium one.
       protoc_label,
     ]
-    if (defined(plugin_host_label)) {
-      # Action depends on generator plugin but for host toolchain only.
-      deps += [ plugin_host_label ]
+
+    if (generate_with_plugin) {
+      inputs += [ plugin_path ]
+      if (defined(invoker.generator_plugin_script_deps)) {
+        # Additional scripts for plugin.
+        inputs += invoker.generator_plugin_script_deps
+      }
+      if (defined(plugin_host_label)) {
+        # Action depends on native generator plugin but for host toolchain only.
+        deps += [ plugin_host_label ]
+      }
     }
+
     if (defined(invoker.deps)) {
       # The deps may have steps that have to run before running protoc.
       deps += invoker.deps
     }
   }
 
   # Option to disable building a library in component build.
   if (defined(invoker.component_build_force_source_set) &&
       invoker.component_build_force_source_set &&
       is_component_build) {
@@ skipping 52 matching lines @@
       ":$action_name",
     ]
 
     # This will link any libraries in the deps (the use of invoker.deps in the
     # action won't link it).
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
   }
 }