archive: add --mtime

Allow users to specify the modification time of archive entries.  The
new option --mtime uses approxidate() to parse a time specification and
overrides the default of using the current time for trees and the commit
time for tags and commits.  It can be used to create a reproducible
archive for a tree, or to use a specific mtime without creating a commit
with GIT_COMMITTER_DATE set.

This implementation doesn't support the negated form of the new option,
i.e. --no-mtime is not accepted.  It is not possible to have no mtime at
all.  We could use the Unix epoch or revert to the default behavior, but
since negation is not necessary for the intended use it's left undecided
for now.

Requested-by: Raul E Rangel <rrangel@chromium.org>
Suggested-by: demerphq <demerphq@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/archive.c b/archive.c
index 81ff76fce9..122860b39d 100644
--- a/archive.c
+++ b/archive.c
@@ -472,6 +472,8 @@ static void parse_treeish_arg(const char **argv,
 		commit_oid = NULL;
 		archive_time = time(NULL);
 	}
+	if (ar_args->mtime_option)
+		archive_time = approxidate(ar_args->mtime_option);
 
 	tree = parse_tree_indirect(&oid);
 	if (!tree)
@@ -586,6 +588,7 @@ static int parse_archive_args(int argc, const char **argv,
 	const char *remote = NULL;
 	const char *exec = NULL;
 	const char *output = NULL;
+	const char *mtime_option = NULL;
 	int compression_level = -1;
 	int verbose = 0;
 	int i;
@@ -607,6 +610,9 @@ static int parse_archive_args(int argc, const char **argv,
 		OPT_BOOL(0, "worktree-attributes", &worktree_attributes,
 			N_("read .gitattributes in working directory")),
 		OPT__VERBOSE(&verbose, N_("report archived files on stderr")),
+		{ OPTION_STRING, 0, "mtime", &mtime_option, N_("time"),
+		  N_("set modification time of archive entries"),
+		  PARSE_OPT_NONEG },
 		OPT_NUMBER_CALLBACK(&compression_level,
 			N_("set compression level"), number_callback),
 		OPT_GROUP(""),
@@ -668,6 +674,7 @@ static int parse_archive_args(int argc, const char **argv,
 	args->base = base;
 	args->baselen = strlen(base);
 	args->worktree_attributes = worktree_attributes;
+	args->mtime_option = mtime_option;
 
 	return argc;
 }