GN: Capture and print stderr from exec_script

tools/gn/exec_process.cc

Index: tools/gn/exec_process.cc
diff --git a/tools/gn/function_exec_script.cc b/tools/gn/exec_process.cc
similarity index 50%
copy from tools/gn/function_exec_script.cc
copy to tools/gn/exec_process.cc
index eb30a6ec399b64aac6ddad66441fdf03baf4aebf..908f9efaab64c2b91a8630914adbaa5d625d1b67 100644
--- a/tools/gn/function_exec_script.cc
+++ b/tools/gn/exec_process.cc
@@ -231,187 +231,3 @@ bool ExecProcess(const CommandLine& cmdline,
 #endif
 
 }  // namespace
-
-const char kExecScript[] = "exec_script";
-const char kExecScript_HelpShort[] =
-    "exec_script: Synchronously run a script and return the output.";
-const char kExecScript_Help[] =
-    "exec_script: Synchronously run a script and return the output.\n"
-    "\n"
-    "  exec_script(filename,\n"
-    "              arguments = [],\n"
-    "              input_conversion = \"\",\n"
-    "              file_dependencies = [])\n"
-    "\n"
-    "  Runs the given script, returning the stdout of the script. The build\n"
-    "  generation will fail if the script does not exist or returns a nonzero\n"
-    "  exit code.\n"
-    "\n"
-    "  The current directory when executing the script will be the root\n"
-    "  build directory. If you are passing file names, you will want to use\n"
-    "  the rebase_path() function to make file names relative to this\n"
-    "  path (see \"gn help rebase_path\").\n"
-    "\n"
-    "Arguments:\n"
-    "\n"
-    "  filename:\n"
-    "      File name of python script to execute. Non-absolute names will\n"
-    "      be treated as relative to the current build file.\n"
-    "\n"
-    "  arguments:\n"
-    "      A list of strings to be passed to the script as arguments.\n"
-    "      May be unspecified or the empty list which means no arguments.\n"
-    "\n"
-    "  input_conversion:\n"
-    "      Controls how the file is read and parsed.\n"
-    "      See \"gn help input_conversion\".\n"
-    "\n"
-    "      If unspecified, defaults to the empty string which causes the\n"
-    "      script result to be discarded. exec script will return None.\n"
-    "\n"
-    "  dependencies:\n"
-    "      (Optional) A list of files that this script reads or otherwise\n"
-    "      depends on. These dependencies will be added to the build result\n"
-    "      such that if any of them change, the build will be regenerated and\n"
-    "      the script will be re-run.\n"
-    "\n"
-    "      The script itself will be an implicit dependency so you do not\n"
-    "      need to list it.\n"
-    "\n"
-    "Example:\n"
-    "\n"
-    "  all_lines = exec_script(\n"
-    "      \"myscript.py\", [some_input], \"list lines\",\n"
-    "      [ rebase_path(\"data_file.txt\", root_build_dir) ])\n"
-    "\n"
-    "  # This example just calls the script with no arguments and discards\n"
-    "  # the result.\n"
-    "  exec_script(\"//foo/bar/myscript.py\")\n";
-
-Value RunExecScript(Scope* scope,
-                    const FunctionCallNode* function,
-                    const std::vector<Value>& args,
-                    Err* err) {
-  if (args.size() < 1 || args.size() > 4) {
-    *err = Err(function->function(), "Wrong number of arguments to exec_script",
-               "I expected between one and four arguments.");
-    return Value();
-  }
-
-  const Settings* settings = scope->settings();
-  const BuildSettings* build_settings = settings->build_settings();
-  const SourceDir& cur_dir = scope->GetSourceDir();
-
-  // Find the python script to run.
-  if (!args[0].VerifyTypeIs(Value::STRING, err))
-    return Value();
-  SourceFile script_source =
-      cur_dir.ResolveRelativeFile(args[0].string_value());
-  base::FilePath script_path = build_settings->GetFullPath(script_source);
-  if (!build_settings->secondary_source_path().empty() &&
-      !base::PathExists(script_path)) {
-    // Fall back to secondary source root when the file doesn't exist.
-    script_path = build_settings->GetFullPathSecondary(script_source);
-  }
-
-  ScopedTrace trace(TraceItem::TRACE_SCRIPT_EXECUTE, script_source.value());
-  trace.SetToolchain(settings->toolchain_label());
-
-  // Add all dependencies of this script, including the script itself, to the
-  // build deps.
-  g_scheduler->AddGenDependency(script_path);
-  if (args.size() == 4) {
-    const Value& deps_value = args[3];
-    if (!deps_value.VerifyTypeIs(Value::LIST, err))
-      return Value();
-
-    for (const auto& dep : deps_value.list_value()) {
-      if (!dep.VerifyTypeIs(Value::STRING, err))
-        return Value();
-      g_scheduler->AddGenDependency(
-          build_settings->GetFullPath(cur_dir.ResolveRelativeFile(
-              dep.string_value())));
-    }
-  }
-
-  // Make the command line.
-  const base::FilePath& python_path = build_settings->python_path();
-  CommandLine cmdline(python_path);
-  cmdline.AppendArgPath(script_path);
-
-  if (args.size() >= 2) {
-    // Optional command-line arguments to the script.
-    const Value& script_args = args[1];
-    if (!script_args.VerifyTypeIs(Value::LIST, err))
-      return Value();
-    for (const auto& arg : script_args.list_value()) {
-      if (!arg.VerifyTypeIs(Value::STRING, err))
-        return Value();
-      cmdline.AppendArg(arg.string_value());
-    }
-  }
-
-  // Log command line for debugging help.
-  trace.SetCommandLine(cmdline);
-  base::TimeTicks begin_exec;
-  if (g_scheduler->verbose_logging()) {
-#if defined(OS_WIN)
-    g_scheduler->Log("Pythoning",
-                     base::UTF16ToUTF8(cmdline.GetCommandLineString()));
-#else
-    g_scheduler->Log("Pythoning", cmdline.GetCommandLineString());
-#endif
-    begin_exec = base::TimeTicks::Now();
-  }
-
-  base::FilePath startup_dir =
-      build_settings->GetFullPath(build_settings->build_dir());
-  // The first time a build is run, no targets will have been written so the
-  // build output directory won't exist. We need to make sure it does before
-  // running any scripts with this as its startup directory, although it will
-  // be relatively rare that the directory won't exist by the time we get here.
-  //
-  // If this shows up on benchmarks, we can cache whether we've done this
-  // or not and skip creating the directory.
-  base::CreateDirectory(startup_dir);
-
-  // Execute the process.
-  // TODO(brettw) set the environment block.
-  std::string output;
-  std::string stderr_output;  // TODO(brettw) not hooked up, see above.
-  int exit_code = 0;
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(kNoExecSwitch)) {
-    if (!ExecProcess(cmdline, startup_dir,
-                     &output, &stderr_output, &exit_code)) {
-      *err = Err(function->function(), "Could not execute python.",
-          "I was trying to execute \"" + FilePathToUTF8(python_path) + "\".");
-      return Value();
-    }
-  }
-  if (g_scheduler->verbose_logging()) {
-    g_scheduler->Log("Pythoning", script_source.value() + " took " +
-        base::Int64ToString(
-            (base::TimeTicks::Now() - begin_exec).InMilliseconds()) +
-        "ms");
-  }
-
-  // TODO(brettw) maybe we need stderr also for reasonable stack dumps.
-  if (exit_code != 0) {
-    std::string msg = "Current dir: " + FilePathToUTF8(startup_dir) +
-        "\nCommand: " + FilePathToUTF8(cmdline.GetCommandLineString()) +
-        "\nReturned " + base::IntToString(exit_code);
-    if (!output.empty())
-      msg += " and printed out:\n\n" + output;
-    else
-      msg += ".";
-    *err = Err(function->function(), "Script returned non-zero exit code.",
-               msg);
-    return Value();
-  }
-
-  // Default to None value for the input conversion if unspecified.
-  return ConvertInputToValue(scope->settings(), output, function,
-                             args.size() >= 3 ? args[2] : Value(), err);
-}
-
-}  // namespace functions