Win32: don't copy the environment twice when spawning child processes

When spawning child processes via start_command(), the environment and all
environment entries are copied twice. First by make_augmented_environ /
copy_environ to merge with child_process.env. Then a second time by
make_environment_block to create a sorted environment block string as
required by CreateProcess.

Move the merge logic to make_environment_block so that we only need to copy
the environment once. This changes semantics of the env parameter: it now
expects a delta (such as child_process.env) rather than a full environment.
This is not a problem as the parameter is only used by start_command()
(all other callers previously passed char **environ, and now pass NULL).

The merge logic no longer xstrdup()s the environment strings, so do_putenv
must not free them. Add a parameter to distinguish this from normal putenv.

Remove the now unused make_augmented_environ / free_environ API.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/run-command.c b/run-command.c
index be07d4ad33..82dd0853a1 100644
--- a/run-command.c
+++ b/run-command.c
@@ -454,7 +454,6 @@ fail_pipe:
 {
 	int fhin = 0, fhout = 1, fherr = 2;
 	const char **sargv = cmd->argv;
-	char **env = environ;
 
 	if (cmd->no_stdin)
 		fhin = open("/dev/null", O_RDWR);
@@ -479,24 +478,19 @@ fail_pipe:
 	else if (cmd->out > 1)
 		fhout = dup(cmd->out);
 
-	if (cmd->env)
-		env = make_augmented_environ(cmd->env);
-
 	if (cmd->git_cmd)
 		cmd->argv = prepare_git_cmd(cmd->argv);
 	else if (cmd->use_shell)
 		cmd->argv = prepare_shell_cmd(cmd->argv);
 
-	cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
-				  fhin, fhout, fherr);
+	cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
+			cmd->dir, fhin, fhout, fherr);
 	failed_errno = errno;
 	if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 		error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 	if (cmd->clean_on_exit && cmd->pid >= 0)
 		mark_child_for_cleanup(cmd->pid);
 
-	if (cmd->env)
-		free_environ(env);
 	if (cmd->git_cmd)
 		free(cmd->argv);