Make "git reset" a builtin.

This replaces the script "git-reset.sh" with "builtin-reset.c".

A few git commands used in the script are called from the builtin also:
"ls-files" to check for unmerged files, "read-tree" for resetting
the index file in "mixed" and "hard" resets, and "update-index" to
refresh at the end in the "mixed" reset and also for the option that
gets selected paths into the index.

The reset option with paths was implemented by Johannes Schindelin.

Since the option that gets selected paths into the index is not
a "reset" like the others because it does not change the HEAD at all,
now the command is showing a warning when the "--mixed" option
is supplied for that purpose.

The following table shows the behaviour of "git reset" for
the different supported options, where X means "changing"
the HEAD, index or working tree:

reset:  --soft  --mixed  --hard  -- <paths>
HEAD       X       X        X        -
index      -       X        X        X
files      -       -        X        -

Signed-off-by: Carlos Rica <jasampler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/builtin.h b/builtin.h
index bb720004af..03ee7bf780 100644
--- a/builtin.h
+++ b/builtin.h
@@ -60,6 +60,7 @@ extern int cmd_read_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_reflog(int argc, const char **argv, const char *prefix);
 extern int cmd_config(int argc, const char **argv, const char *prefix);
 extern int cmd_rerere(int argc, const char **argv, const char *prefix);
+extern int cmd_reset(int argc, const char **argv, const char *prefix);
 extern int cmd_rev_list(int argc, const char **argv, const char *prefix);
 extern int cmd_rev_parse(int argc, const char **argv, const char *prefix);
 extern int cmd_revert(int argc, const char **argv, const char *prefix);