When we get 40 hex digits, we immediately assume it's an SHA-1. This
is the right thing to do because we have no way else to specify an
object. If there is a ref with the same object name, it will be
ignored. Warn the user about this case because the ref with full
object name is likely a mistake, for example
git checkout -b $empty_var $(git rev-parse something)
advice.object_name_warning is not documented because frankly people
should not be aware about it until they encounter this situation.
While at there, warn about ambiguation with abbreviated SHA-1 too.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
advice.c | 2 ++
advice.h | 1 +
sha1_name.c | 25 +++++++++++++++++++++++--
t/t1512-rev-parse-disambiguation.sh | 18 ++++++++++++++++++
4 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/advice.c b/advice.c
index 780f58d..22abde9 100644
--- a/advice.c
+++ b/advice.c
@@ -12,6 +12,7 @@ int advice_commit_before_merge = 1;
int advice_resolve_conflict = 1;
int advice_implicit_identity = 1;
int advice_detached_head = 1;
+int advice_object_name_warning = 1;
static struct {
const char *name;
@@ -29,6 +30,7 @@ static struct {
{ "resolveconflict", &advice_resolve_conflict },
{ "implicitidentity", &advice_implicit_identity },
{ "detachedhead", &advice_detached_head },
+ { "object_name_warning", &advice_object_name_warning },
/* make this an alias for backward compatibility */
{ "pushnonfastforward", &advice_push_update_rejected }
diff --git a/advice.h b/advice.h
index fad36df..24d5420 100644
--- a/advice.h
+++ b/advice.h
@@ -15,6 +15,7 @@ extern int advice_commit_before_merge;
extern int advice_resolve_conflict;
extern int advice_implicit_identity;
extern int advice_detached_head;
+extern int advice_object_name_warning;
int git_default_advice_config(const char *var, const char *value);
void advise(const char *advice, ...);
diff --git a/sha1_name.c b/sha1_name.c
index 95003c7..502d107 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -435,12 +435,31 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned l
static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
{
static const char *warn_msg = "refname '%.*s' is ambiguous.";
+ static const char *object_name_msg = N_(
+ "Git normally never creates a ref that ends with 40 hex characters\n"
+ "because it will be ignored when you just specify 40-hex. These refs\n"
+ "may be created by mistake. For example,\n"
+ "\n"
+ " git checkout -b $br $(git rev-parse ...)\n"
+ "\n"
+ "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
+ "examine these refs and maybe delete them. Turn this message off by\n"
+ "running \"git config advice.object_name_warning false\"");
+ unsigned char tmp_sha1[20];
char *real_ref = NULL;
int refs_found = 0;
int at, reflog_len;
- if (len == 40 && !get_sha1_hex(str, sha1))
+ if (len == 40 && !get_sha1_hex(str, sha1)) {
+ refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
+ if (refs_found > 0 && warn_ambiguous_refs) {
+ warning(warn_msg, len, str);
+ if (advice_object_name_warning)
+ fprintf(stderr, "%s\n", _(object_name_msg));
+ }
+ free(real_ref);
return 0;
+ }
/* basic@{time or number or -number} format to query ref-log */
reflog_len = at = 0;
@@ -481,7 +500,9 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
if (!refs_found)
return -1;
- if (warn_ambiguous_refs && refs_found > 1)
+ if (warn_ambiguous_refs &&
+ (refs_found > 1 ||
+ !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
warning(warn_msg, len, str);
if (reflog_len) {
diff --git a/t/t1512-rev-parse-disambiguation.sh b/t/t1512-rev-parse-disambiguation.sh
index 6b3d797..db22808 100755
--- a/t/t1512-rev-parse-disambiguation.sh
+++ b/t/t1512-rev-parse-disambiguation.sh
@@ -261,4 +261,22 @@ test_expect_success 'rev-parse --disambiguate' '
test "$(sed -e "s/^\(.........\).*/\1/" actual | sort -u)" = 000000000
'
+test_expect_success 'ambiguous 40-hex ref' '
+ TREE=$(git mktree </dev/null) &&
+ REF=`git rev-parse HEAD` &&
+ VAL=$(git commit-tree $TREE </dev/null) &&
+ git update-ref refs/heads/$REF $VAL &&
+ test `git rev-parse $REF 2>err` = $REF &&
+ grep "refname.*${REF}.*ambiguous" err
+'
+
+test_expect_success 'ambiguous short sha1 ref' '
+ TREE=$(git mktree </dev/null) &&
+ REF=`git rev-parse --short HEAD` &&
+ VAL=$(git commit-tree $TREE </dev/null) &&
+ git update-ref refs/heads/$REF $VAL &&
+ test `git rev-parse $REF 2>err` = $VAL &&
+ grep "refname.*${REF}.*ambiguous" err
+'
+
test_done
--
1.8.2.83.gc99314b
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