timestamp_t: a new data type for timestamps

Git's source code assumes that unsigned long is at least as precise as
time_t. Which is incorrect, and causes a lot of problems, in particular
where unsigned long is only 32-bit (notably on Windows, even in 64-bit
versions).

So let's just use a more appropriate data type instead. In preparation
for this, we introduce the new `timestamp_t` data type.

By necessity, this is a very, very large patch, as it has to replace all
timestamps' data type in one go.

As we will use a data type that is not necessarily identical to `time_t`,
we need to be very careful to use `time_t` whenever we interact with the
system functions, and `timestamp_t` everywhere else.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/technical/api-parse-options.txt

@@ -183,13 +183,13 @@ There are some macros to easily define options:
 	scale the provided value by 1024, 1024^2 or 1024^3 respectively.
 	The scaled value is put into `unsigned_long_var`.
-`OPT_DATE(short, long, &int_var, description)`::
+`OPT_DATE(short, long, &timestamp_t_var, description)`::
 	Introduce an option with date argument, see `approxidate()`.
-	The timestamp is put into `int_var`.
-`OPT_EXPIRY_DATE(short, long, &int_var, description)`::
+	The timestamp is put into `timestamp_t_var`.
+`OPT_EXPIRY_DATE(short, long, &timestamp_t_var, description)`::
 	Introduce an option with expiry date argument, see `parse_expiry_date()`.
-	The timestamp is put into `int_var`.
+	The timestamp is put into `timestamp_t_var`.
 `OPT_CALLBACK(short, long, &var, arg_str, description, func_ptr)`::
 	Introduce an option with argument.

archive-tar.c

@@ -27,9 +27,12 @@ static int write_tar_filter_archive(const struct archiver *ar,
  */
 #if ULONG_MAX == 0xFFFFFFFF
 #define USTAR_MAX_SIZE ULONG_MAX
-#define USTAR_MAX_MTIME ULONG_MAX
 #else
-#define USTAR_MAX_SIZE 077777777777UL
+#define USTAR_MAX_SIZE 077777777777ULL
+#endif
+#if TIME_MAX == 0xFFFFFFFF
+#define USTAR_MAX_MTIME TIME_MAX
+#else
 #define USTAR_MAX_MTIME 077777777777UL
 #endif

archive-zip.c

@@ -545,9 +545,17 @@ static void write_zip_trailer(const unsigned char *sha1)
 		write_or_die(1, sha1_to_hex(sha1), GIT_SHA1_HEXSZ);
 }
-static void dos_time(time_t *time, int *dos_date, int *dos_time)
+static void dos_time(timestamp_t *timestamp, int *dos_date, int *dos_time)
 {
-	struct tm *t = localtime(time);
+	time_t time;
+	struct tm *t;
+
+	if (date_overflows(*timestamp))
+		die("timestamp too large for this system: %"PRItime,
+		    *timestamp);
+	time = (time_t)*timestamp;
+	t = localtime(&time);
+	*timestamp = time;
 	*dos_date = t->tm_mday + (t->tm_mon + 1) * 32 +
 	            (t->tm_year + 1900 - 1980) * 512;

archive.h

@@ -9,7 +9,7 @@ struct archiver_args {
 	struct tree *tree;
 	const unsigned char *commit_sha1;
 	const struct commit *commit;
-	time_t time;
+	timestamp_t time;
 	struct pathspec pathspec;
 	unsigned int verbose : 1;
 	unsigned int worktree_attributes : 1;

builtin/am.c

@@ -877,7 +877,7 @@ static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 		if (skip_prefix(sb.buf, "# User ", &str))
 			fprintf(out, "From: %s\n", str);
 		else if (skip_prefix(sb.buf, "# Date ", &str)) {
-			unsigned long timestamp;
+			timestamp_t timestamp;
 			long tz, tz2;
 			char *end;

builtin/blame.c

@@ -1561,13 +1561,13 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
 struct commit_info {
 	struct strbuf author;
 	struct strbuf author_mail;
-	unsigned long author_time;
+	timestamp_t author_time;
 	struct strbuf author_tz;
 	/* filled only when asked for details */
 	struct strbuf committer;
 	struct strbuf committer_mail;
-	unsigned long committer_time;
+	timestamp_t committer_time;
 	struct strbuf committer_tz;
 	struct strbuf summary;
@@ -1578,7 +1578,7 @@ struct commit_info {
  */
 static void get_ac_line(const char *inbuf, const char *what,
 	struct strbuf *name, struct strbuf *mail,
-	unsigned long *time, struct strbuf *tz)
+	timestamp_t *time, struct strbuf *tz)
 {
 	struct ident_split ident;
 	size_t len, maillen, namelen;
@@ -1837,7 +1837,7 @@ static void assign_blame(struct scoreboard *sb, int opt)
 	stop_progress(&pi.progress);
 }
-static const char *format_time(unsigned long time, const char *tz_str,
+static const char *format_time(timestamp_t time, const char *tz_str,
 			       int show_raw_time)
 {
 	static struct strbuf time_buf = STRBUF_INIT;

builtin/fsck.c

@@ -397,7 +397,7 @@ static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 static int default_refs;
 static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
-	unsigned long timestamp)
+	timestamp_t timestamp)
 {
 	struct object *obj;
@@ -418,7 +418,7 @@ static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
 }
 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, unsigned long timestamp, int tz,
+		const char *email, timestamp_t timestamp, int tz,
 		const char *message, void *cb_data)
 {
 	const char *refname = cb_data;

builtin/gc.c

@@ -33,7 +33,7 @@ static int aggressive_window = 250;
 static int gc_auto_threshold = 6700;
 static int gc_auto_pack_limit = 50;
 static int detach_auto = 1;
-static unsigned long gc_log_expire_time;
+static timestamp_t gc_log_expire_time;
 static const char *gc_log_expire = "1.day.ago";
 static const char *prune_expire = "2.weeks.ago";
 static const char *prune_worktrees_expire = "3.months.ago";

builtin/log.c

@@ -911,7 +911,7 @@ static void gen_message_id(struct rev_info *info, char *base)
 {
 	struct strbuf buf = STRBUF_INIT;
 	strbuf_addf(&buf, "%s.%"PRItime".git.%s", base,
-		    (unsigned long) time(NULL),
+		    (timestamp_t) time(NULL),
 		    git_committer_info(IDENT_NO_NAME|IDENT_NO_DATE|IDENT_STRICT));
 	info->message_id = strbuf_detach(&buf, NULL);
 }

builtin/merge-base.c

@@ -132,7 +132,7 @@ static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 }
 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
-				  const char *ident, unsigned long timestamp,
+				  const char *ident, timestamp_t timestamp,
 				  int tz, const char *message, void *cbdata)
 {
 	struct rev_collect *revs = cbdata;

builtin/name-rev.c

@@ -10,7 +10,7 @@
 typedef struct rev_name {
 	const char *tip_name;
-	unsigned long taggerdate;
+	timestamp_t taggerdate;
 	int generation;
 	int distance;
 } rev_name;
@@ -21,7 +21,7 @@ static long cutoff = LONG_MAX;
 #define MERGE_TRAVERSAL_WEIGHT 65535
 static void name_rev(struct commit *commit,
-		const char *tip_name, unsigned long taggerdate,
+		const char *tip_name, timestamp_t taggerdate,
 		int generation, int distance,
 		int deref)
 {
@@ -146,7 +146,7 @@ static int name_ref(const char *path, const struct object_id *oid, int flags, vo
 	struct name_ref_data *data = cb_data;
 	int can_abbreviate_output = data->tags_only && data->name_only;
 	int deref = 0;
-	unsigned long taggerdate = ULONG_MAX;
+	timestamp_t taggerdate = TIME_MAX;
 	if (data->tags_only && !starts_with(path, "refs/tags/"))
 		return 0;

builtin/pack-objects.c

@@ -44,7 +44,7 @@ static uint32_t nr_result, nr_written;
 static int non_empty;
 static int reuse_delta = 1, reuse_object = 1;
 static int keep_unreachable, unpack_unreachable, include_tag;
-static unsigned long unpack_unreachable_expiration;
+static timestamp_t unpack_unreachable_expiration;
 static int pack_loose_unreachable;
 static int local;
 static int have_non_local_packs;
@@ -2675,7 +2675,7 @@ static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
 static struct oid_array recent_objects;
 static int loosened_object_can_be_discarded(const struct object_id *oid,
-					    unsigned long mtime)
+					    timestamp_t mtime)
 {
 	if (!unpack_unreachable_expiration)
 		return 0;

builtin/prune.c

@@ -13,7 +13,7 @@ static const char * const prune_usage[] = {
 };
 static int show_only;
 static int verbose;
-static unsigned long expire;
+static timestamp_t expire;
 static int show_progress = -1;
 static int prune_tmp_file(const char *fullpath)
@@ -111,7 +111,7 @@ int cmd_prune(int argc, const char **argv, const char *prefix)
 	};
 	char *s;
-	expire = ULONG_MAX;
+	expire = TIME_MAX;
 	save_commit_buffer = 0;
 	check_replace_refs = 0;
 	ref_paranoia = 1;

builtin/receive-pack.c

@@ -78,7 +78,7 @@ static const char *NONCE_OK = "OK";
 static const char *NONCE_SLOP = "SLOP";
 static const char *nonce_status;
 static long nonce_stamp_slop;
-static unsigned long nonce_stamp_slop_limit;
+static timestamp_t nonce_stamp_slop_limit;
 static struct ref_transaction *transaction;
 static enum {
@@ -454,7 +454,7 @@ static void hmac_sha1(unsigned char *out,
 	git_SHA1_Final(out, &ctx);
 }
-static char *prepare_push_cert_nonce(const char *path, unsigned long stamp)
+static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
 {
 	struct strbuf buf = STRBUF_INIT;
 	unsigned char sha1[20];
@@ -496,7 +496,7 @@ static char *find_header(const char *msg, size_t len, const char *key)
 static const char *check_nonce(const char *buf, size_t len)
 {
 	char *nonce = find_header(buf, len, "nonce");
-	unsigned long stamp, ostamp;
+	timestamp_t stamp, ostamp;
 	char *bohmac, *expect = NULL;
 	const char *retval = NONCE_BAD;

builtin/reflog.c

@@ -16,14 +16,14 @@ static const char reflog_delete_usage[] =
 static const char reflog_exists_usage[] =
 "git reflog exists <ref>";
-static unsigned long default_reflog_expire;
-static unsigned long default_reflog_expire_unreachable;
+static timestamp_t default_reflog_expire;
+static timestamp_t default_reflog_expire_unreachable;
 struct cmd_reflog_expire_cb {
 	struct rev_info revs;
 	int stalefix;
-	unsigned long expire_total;
-	unsigned long expire_unreachable;
+	timestamp_t expire_total;
+	timestamp_t expire_unreachable;
 	int recno;
 };
@@ -219,7 +219,7 @@ static int keep_entry(struct commit **it, unsigned char *sha1)
 static void mark_reachable(struct expire_reflog_policy_cb *cb)
 {
 	struct commit_list *pending;
-	unsigned long expire_limit = cb->mark_limit;
+	timestamp_t expire_limit = cb->mark_limit;
 	struct commit_list *leftover = NULL;
 	for (pending = cb->mark_list; pending; pending = pending->next)
@@ -284,7 +284,7 @@ static int unreachable(struct expire_reflog_policy_cb *cb, struct commit *commit
  * Return true iff the specified reflog entry should be expired.
  */
 static int should_expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
-				    const char *email, unsigned long timestamp, int tz,
+				    const char *email, timestamp_t timestamp, int tz,
 				    const char *message, void *cb_data)
 {
 	struct expire_reflog_policy_cb *cb = cb_data;
@@ -392,8 +392,8 @@ static int collect_reflog(const char *ref, const struct object_id *oid, int unus
 static struct reflog_expire_cfg {
 	struct reflog_expire_cfg *next;
-	unsigned long expire_total;
-	unsigned long expire_unreachable;
+	timestamp_t expire_total;
+	timestamp_t expire_unreachable;
 	char pattern[FLEX_ARRAY];
 } *reflog_expire_cfg, **reflog_expire_cfg_tail;
@@ -415,7 +415,7 @@ static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
 	return ent;
 }
-static int parse_expire_cfg_value(const char *var, const char *value, unsigned long *expire)
+static int parse_expire_cfg_value(const char *var, const char *value, timestamp_t *expire)
 {
 	if (!value)
 		return config_error_nonbool(var);
@@ -433,7 +433,7 @@ static int reflog_expire_config(const char *var, const char *value, void *cb)
 {
 	const char *pattern, *key;
 	int pattern_len;
-	unsigned long expire;
+	timestamp_t expire;
 	int slot;
 	struct reflog_expire_cfg *ent;
@@ -515,7 +515,7 @@ static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, c
 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 {
 	struct expire_reflog_policy_cb cb;
-	unsigned long now = time(NULL);
+	timestamp_t now = time(NULL);
 	int i, status, do_all;
 	int explicit_expiry = 0;
 	unsigned int flags = 0;
@@ -616,7 +616,7 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 }
 static int count_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, unsigned long timestamp, int tz,
+		const char *email, timestamp_t timestamp, int tz,
 		const char *message, void *cb_data)
 {
 	struct expire_reflog_policy_cb *cb = cb_data;

builtin/show-branch.c

@@ -735,7 +735,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 			base = strtoul(reflog_base, &ep, 10);
 			if (*ep) {
 				/* Ah, that is a date spec... */
-				unsigned long at;
+				timestamp_t at;
 				at = approxidate(reflog_base);
 				read_ref_at(ref, flags, at, -1, oid.hash, NULL,
 					    NULL, NULL, &base);
@@ -746,7 +746,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 			char *logmsg;
 			char *nth_desc;
 			const char *msg;
-			unsigned long timestamp;
+			timestamp_t timestamp;
 			int tz;
 			if (read_ref_at(ref, flags, 0, base+i, oid.hash, &logmsg,

builtin/worktree.c

@@ -30,7 +30,7 @@ struct add_opts {
 static int show_only;
 static int verbose;
-static unsigned long expire;
+static timestamp_t expire;
 static int prune_worktree(const char *id, struct strbuf *reason)
 {
@@ -131,7 +131,7 @@ static int prune(int ac, const char **av, const char *prefix)
 		OPT_END()
 	};
-	expire = ULONG_MAX;
+	expire = TIME_MAX;
 	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
 	if (ac)
 		usage_with_options(worktree_usage, options);

bundle.c

@@ -211,7 +211,7 @@ static int is_tag_in_date_range(struct object *tag, struct rev_info *revs)
 	unsigned long size;
 	enum object_type type;
 	char *buf = NULL, *line, *lineend;
-	unsigned long date;
+	timestamp_t date;
 	int result = 1;
 	if (revs->max_age == -1 && revs->min_age == -1)

cache.h

@@ -1476,18 +1476,18 @@ struct date_mode {
 #define DATE_MODE(t) date_mode_from_type(DATE_##t)
 struct date_mode *date_mode_from_type(enum date_mode_type type);
-const char *show_date(unsigned long time, int timezone, const struct date_mode *mode);
-void show_date_relative(unsigned long time, int tz, const struct timeval *now,
+const char *show_date(timestamp_t time, int timezone, const struct date_mode *mode);
+void show_date_relative(timestamp_t time, int tz, const struct timeval *now,
 			struct strbuf *timebuf);
 int parse_date(const char *date, struct strbuf *out);
-int parse_date_basic(const char *date, unsigned long *timestamp, int *offset);
-int parse_expiry_date(const char *date, unsigned long *timestamp);
+int parse_date_basic(const char *date, timestamp_t *timestamp, int *offset);
+int parse_expiry_date(const char *date, timestamp_t *timestamp);
 void datestamp(struct strbuf *out);
 #define approxidate(s) approxidate_careful((s), NULL)
-unsigned long approxidate_careful(const char *, int *);
-unsigned long approxidate_relative(const char *date, const struct timeval *now);
+timestamp_t approxidate_careful(const char *, int *);
+timestamp_t approxidate_relative(const char *date, const struct timeval *now);
 void parse_date_format(const char *format, struct date_mode *mode);
-int date_overflows(unsigned long date);
+int date_overflows(timestamp_t date);
 #define IDENT_STRICT	       1
 #define IDENT_NO_DATE	       2

commit.c

@@ -66,7 +66,7 @@ struct commit *lookup_commit_reference_by_name(const char *name)
 	return commit;
 }
-static unsigned long parse_commit_date(const char *buf, const char *tail)
+static timestamp_t parse_commit_date(const char *buf, const char *tail)
 {
 	const char *dateptr;
@@ -473,8 +473,8 @@ struct commit_list * commit_list_insert_by_date(struct commit *item, struct comm
 static int commit_list_compare_by_date(const void *a, const void *b)
 {
-	unsigned long a_date = ((const struct commit_list *)a)->item->date;
-	unsigned long b_date = ((const struct commit_list *)b)->item->date;
+	timestamp_t a_date = ((const struct commit_list *)a)->item->date;
+	timestamp_t b_date = ((const struct commit_list *)b)->item->date;
 	if (a_date < b_date)
 		return 1;
 	if (a_date > b_date)
@@ -598,7 +598,7 @@ static void record_author_date(struct author_date_slab *author_date,
 	const char *ident_line;
 	size_t ident_len;
 	char *date_end;
-	unsigned long date;
+	timestamp_t date;
 	ident_line = find_commit_header(buffer, "author", &ident_len);
 	if (!ident_line)
@@ -621,8 +621,8 @@ static int compare_commits_by_author_date(const void *a_, const void *b_,
 {
 	const struct commit *a = a_, *b = b_;
 	struct author_date_slab *author_date = cb_data;
-	unsigned long a_date = *(author_date_slab_at(author_date, a));
-	unsigned long b_date = *(author_date_slab_at(author_date, b));
+	timestamp_t a_date = *(author_date_slab_at(author_date, a));
+	timestamp_t b_date = *(author_date_slab_at(author_date, b));
 	/* newer commits with larger date first */
 	if (a_date < b_date)