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[PATCH 5/5] git-config: always treat --int as 64-bit internally

From
Jeff King <peff@peff.net>
Date
Sep 8, 2013, 08:40 UTC
Message-ID
<20130908084002.GE29554@sigill.intra.peff.net>
In-Reply-To
<20130908082724.GA27184@sigill.intra.peff.net>

When you run "git config --int", the maximum size of integer you get depends on how git was compiled, and what it considers to be an "int".

This is almost useful, because your scripts calling "git config" will behave similarly to git internally. But relying on this is dubious; you have to actually know how git treats each value internally (e.g., int versus unsigned long), which is not documented and is subject to change. And even if you know it is "unsigned long", we do not have a git-config option to match that behavior.

Furthermore, you may simply be asking git to store a value on your behalf (e.g., configuration for a hook). In that case, the relevant range check has nothing at all to do with git, but rather with whatever scripting tools you are using (and git has no way of knowing what the appropriate range is there).

Not only is the range check useless, but it is actively harmful, as there is no way at all for scripts to look at config variables with large values. For instance, one cannot reliably get the value of pack.packSizeLimit via git-config. On an LP64 system, git happily uses a 64-bit "unsigned long" internally to represent the value, but the script cannot read any value over 2G.

Ideally, the "--int" option would simply represent an arbitrarily large integer. For practical purposes, however, a 64-bit integer is large enough, and is much easier to implement (and if somebody overflows it, we will still notice the problem, and not simply return garbage).

Signed-off-by: Jeff King <peff@peff.net>
---
I kind of picked 64-bit as "big enough". But I suppose we could also go
with intmax_t. The only thing we can't do is an unsigned value.

Also, this is the first use of PRId64. I notice we have compatibility macros for PRIu*, but I'm not sure what to put in one for PRId64.

 builtin/config.c       |  7 ++++---
 cache.h                |  1 +
 config.c               | 17 +++++++++++++++++
 t/t1300-repo-config.sh |  7 +++++++
 4 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/builtin/config.c b/builtin/config.c
index 4010c43..8b182d2 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -128,7 +128,8 @@ static int collect_config(const char *key_, const char *value_, void *cb)
 		must_print_delim = 1;
 	}
 	if (types == TYPE_INT)
-		sprintf(value, "%d", git_config_int(key_, value_?value_:""));
+		sprintf(value, "%"PRId64,
+			git_config_int64(key_, value_ ? value_ : ""));
 	else if (types == TYPE_BOOL)
 		vptr = git_config_bool(key_, value_) ? "true" : "false";
 	else if (types == TYPE_BOOL_OR_INT) {
@@ -265,8 +266,8 @@ static char *normalize_value(const char *key, const char *value)
 	else {
 		normalized = xmalloc(64);
 		if (types == TYPE_INT) {
-			int v = git_config_int(key, value);
-			sprintf(normalized, "%d", v);
+			int64_t v = git_config_int64(key, value);
+			sprintf(normalized, "%"PRId64, v);
 		}
 		else if (types == TYPE_BOOL)
 			sprintf(normalized, "%s",
diff --git a/cache.h b/cache.h
index 85b544f..ac4525a 100644
--- a/cache.h
+++ b/cache.h
@@ -1190,6 +1190,7 @@ extern int git_config_int(const char *, const char *);
 extern int git_config_early(config_fn_t fn, void *, const char *repo_config);
 extern int git_parse_ulong(const char *, unsigned long *);
 extern int git_config_int(const char *, const char *);
+extern int64_t git_config_int64(const char *, const char *);
 extern unsigned long git_config_ulong(const char *, const char *);
 extern int git_config_bool_or_int(const char *, const char *, int *);
 extern int git_config_bool(const char *, const char *);
diff --git a/config.c b/config.c
index 87f87ba..6588cf5 100644
--- a/config.c
+++ b/config.c
@@ -534,6 +534,15 @@ static int git_parse_int(const char *value, int *ret)
 	return 1;
 }
 
+static int git_parse_int64(const char *value, int64_t *ret)
+{
+	intmax_t tmp;
+	if (!git_parse_signed(value, &tmp, maximum_signed_value_of_type(int64_t)))
+		return 0;
+	*ret = tmp;
+	return 1;
+}
+
 int git_parse_ulong(const char *value, unsigned long *ret)
 {
 	uintmax_t tmp;
@@ -565,6 +574,14 @@ int git_config_int(const char *name, const char *value)
 	return ret;
 }
 
+int64_t git_config_int64(const char *name, const char *value)
+{
+	int64_t ret;
+	if (!git_parse_int64(value, &ret))
+		die_bad_number(name, value);
+	return ret;
+}
+
 unsigned long git_config_ulong(const char *name, const char *value)
 {
 	unsigned long ret;
diff --git a/t/t1300-repo-config.sh b/t/t1300-repo-config.sh
index 20aee6e..b66c632 100755
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-repo-config.sh
@@ -652,6 +652,13 @@ test_expect_success numbers '
 	test_cmp expect actual
 '
 
+test_expect_success '--int is at least 64 bits' '
+	git config giga.watts 121g &&
+	echo 129922760704 >expect &&
+	git config --int --get giga.watts >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'invalid unit' '
 	git config aninvalid.unit "1auto" &&
 	echo 1auto >expect &&
-- 
1.8.4.2.g87d4a77
Previous: Jeff KingNext: Junio C Hamano
Message 24 of 25 in “git-config and large integers”
  1. 0/2 git-config and large integersJeff King, Aug 20, 2013
  2. 1/2 config: properly range-check integer valuesJeff King, Aug 20, 2013
  3. Jonathan NiederAug 20, 2013
  4. Jeff KingAug 21, 2013
  5. Stefan BellerAug 20, 2013
  6. Jeff KingAug 20, 2013
  7. 2/2 teach git-config to output large integersJeff King, Aug 20, 2013
  8. Jonathan NiederAug 20, 2013
  9. Jeff KingAug 21, 2013
  10. Jonathan NiederAug 21, 2013
  11. Jeff KingAug 21, 2013
  12. Jonathan NiederAug 21, 2013
  13. Junio C HamanoAug 20, 2013
  14. Junio C HamanoAug 20, 2013
  15. Jeff KingAug 21, 2013
  16. Jeff KingAug 21, 2013
  17. 0/5 git-config and large integersJeff King, Sep 8, 2013
  18. 1/5 config: factor out integer parsing from range checksJeff King, Sep 8, 2013
  19. 2/5 config: properly range-check integer valuesJeff King, Sep 8, 2013
  20. 3/5 config: set errno in numeric git_parse_* functionsJeff King, Sep 8, 2013
  21. Eric SunshineSep 9, 2013
  22. Jeff KingSep 9, 2013
  23. 4/5 config: make numeric parsing errors more clearJeff King, Sep 8, 2013
  24. 5/5 git-config: always treat --int as 64-bit internallyJeff King, Sep 8, 2013
  25. Junio C HamanoSep 9, 2013

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