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, 6 deletions

diff --git a/compat/mingw.h b/compat/mingw.h
index 828d97760c..3851857c2d 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -357,12 +357,8 @@ int mingw_offset_1st_component(const char *path);
 void mingw_open_html(const char *path);
 #define open_html mingw_open_html
 
-/*
- * helpers
- */
-
-char **make_augmented_environ(const char *const *vars);
-void free_environ(char **env);
+void mingw_mark_as_git_dir(const char *dir);
+#define mark_as_git_dir mingw_mark_as_git_dir
 
 /**
  * Converts UTF-8 encoded string to UTF-16LE.