[PATCH 17/20] abbrev: unify the handling of empty values

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

For no good reason the --abbrev= command-line option was less strict
than the core.abbrev config option, which came down to the latter
using git_config_int() which rejects an empty string, but the rest of
the parsing using strtoul() which will convert it to 0.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 diff.c             |  2 ++
 parse-options-cb.c |  2 ++
 revision.c         |  2 ++
 t/t0014-abbrev.sh  | 22 ++++++++--------------
 4 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/diff.c b/diff.c
index 75935322f1..cab79d24ab 100644
--- a/diff.c
+++ b/diff.c
@@ -4802,6 +4802,8 @@ int diff_opt_parse(struct diff_options *options,
 		options->abbrev = DEFAULT_ABBREV;
 	else if (skip_prefix(arg, "--abbrev=", &arg)) {
 		char *end;
+		if (!strcmp(arg, ""))
+			die("--abbrev expects a value, got '%s'", arg);
 		options->abbrev = strtoul(arg, &end, 10);
 		if (*end)
 			die("--abbrev expects a numerical value, got '%s'", arg);
diff --git a/parse-options-cb.c b/parse-options-cb.c
index e3cd87fbd6..aa9984f164 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -16,6 +16,8 @@ int parse_opt_abbrev_cb(const struct option *opt, const char *arg, int unset)
 	if (!arg) {
 		v = unset ? 0 : DEFAULT_ABBREV;
 	} else {
+		if (!strcmp(arg, ""))
+			return opterror(opt, "expects a value", 0);
 		v = strtol(arg, (char **)&arg, 10);
 		if (*arg)
 			return opterror(opt, "expects a numerical value", 0);
diff --git a/revision.c b/revision.c
index aa87afa77f..d39a292895 100644
--- a/revision.c
+++ b/revision.c
@@ -2048,6 +2048,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->abbrev = DEFAULT_ABBREV;
 	} else if (skip_prefix(arg, "--abbrev=", &optarg)) {
 		char *end;
+		if (!strcmp(optarg, ""))
+			die("--abbrev expects a value, got '%s'", optarg);
 		revs->abbrev = strtoul(optarg, &end, 10);
 		if (*end)
 			die("--abbrev expects a numerical value, got '%s'", optarg);
diff --git a/t/t0014-abbrev.sh b/t/t0014-abbrev.sh
index 203fe316b9..8448f78560 100755
--- a/t/t0014-abbrev.sh
+++ b/t/t0014-abbrev.sh
@@ -38,23 +38,17 @@ test_expect_success 'abbrev empty value handling differs ' '
 	test_must_fail git -c core.abbrev= log -1 --pretty=format:%h 2>stderr &&
 	test_i18ngrep "bad numeric config value.*invalid unit" stderr &&
 
-	git branch -v --abbrev= | cut_tr_d_n_field_n 3 >branch &&
-	test_byte_count = 40 branch &&
+	test_must_fail git branch -v --abbrev= 2>stderr &&
+	test_i18ngrep "expects a value" stderr &&
 
-	git log --abbrev= -1 --pretty=format:%h >log &&
-	test_byte_count = 4 log &&
+	test_must_fail git log --abbrev= -1 --pretty=format:%h 2>stderr &&
+	test_i18ngrep "expects a value" stderr &&
 
-	git diff --raw --abbrev= HEAD~ >diff &&
-	cut_tr_d_n_field_n 3 <diff >diff.3 &&
-	test_byte_count = 4 diff.3 &&
-	cut_tr_d_n_field_n 4 <diff >diff.4 &&
-	test_byte_count = 4 diff.4 &&
+	test_must_fail git diff --raw --abbrev= HEAD~ 2>stderr &&
+	test_i18ngrep "expects a value" stderr &&
 
-	test_must_fail git diff --raw --abbrev= --no-index X Y >diff &&
-	cut_tr_d_n_field_n 3 <diff >diff.3 &&
-	test_byte_count = 4 diff.3 &&
-	cut_tr_d_n_field_n 4 <diff >diff.4 &&
-	test_byte_count = 4 diff.4
+	test_must_fail git diff --raw --abbrev= --no-index X Y 2>stderr &&
+	test_i18ngrep "expects a value" stderr
 '
 
 test_expect_success 'abbrev non-integer value handling differs ' '
-- 
2.17.0.290.gded63e768a