Hi Junio & Peff,
On Thu, 14 Mar 2019, Junio C Hamano wrote:
> "Johannes Schindelin via GitGitGadget" <gitgitgadget@xxxxxxxxx>
> writes:
>
> > @@ -442,6 +442,18 @@ static enum get_oid_result get_short_oid(const char *name, int len,
> > find_short_packed_object(&ds);
> > status = finish_object_disambiguation(&ds, oid);
> >
> > + /*
> > + * If we didn't find it, do the usual reprepare() slow-path,
> > + * since the object may have recently been added to the repository
> > + * or migrated from loose to packed.
> > + */
> > + if (status == MISSING_OBJECT) {
> > + reprepare_packed_git(the_repository);
> > + find_short_object_filename(&ds);
> > + find_short_packed_object(&ds);
> > + status = finish_object_disambiguation(&ds, oid);
> > + }
> > +
>
> This looks obviously correct, but two things that made me wonder
> briefly were:
>
> 1. is reprepare_packed_git() a bit too heavy-weight, if the only
> thing we are addressing is the loose-object cache going stale?
>
> 2. is there a way to cleanly avoid the three-line duplicate?
>
> My tentative answers are (1) even if it is, but get_short_oid() is
> already heavy-weight enough; it won't be worth restructuring the
> code to make it possible to clear only the loose-object cache, and
> (2) a loop that runs twice when the first result is MISSING_OBJECT
> and otherwise leaves after once would need an extra variable, its
> iniialization, check and increment, which is more than what we might
> save with such a restructuring, so it won't be worth pursuing.
>
> But others may have better ideas, as always ;-)
Peff tried with a function, but I think that this would actually be a
really appropriate occasion for a well-placed `goto`:
-- snip --
diff --git a/sha1-name.c b/sha1-name.c
index 6dda2c16df10..36a66026964a 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -415,7 +415,7 @@ static enum get_oid_result get_short_oid(const char *name, int len,
struct object_id *oid,
unsigned flags)
{
- int status;
+ int status, attempts = 0;
struct disambiguate_state ds;
int quietly = !!(flags & GET_OID_QUIETLY);
@@ -438,10 +438,21 @@ static enum get_oid_result get_short_oid(const char *name, int len,
else
ds.fn = default_disambiguate_hint;
+try_again:
find_short_object_filename(&ds);
find_short_packed_object(&ds);
status = finish_object_disambiguation(&ds, oid);
+ /*
+ * If we did not find it, do the usual reprepare() slow-path, since the
+ * object may have recently been added to the repository or migrated
+ * from loose to packed.
+ */
+ if (status == MISSING_OBJECT && !attempts++) {
+ reprepare_packed_git(the_repository);
+ goto try_again;
+ }
+
if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
struct oid_array collect = OID_ARRAY_INIT;
-- snap --
Granted, it's 11 lines inserted and one changed as opposed to 12 lines
inserted, but it does make the code DRYer (and therefore slightly safer to
modify in the future). I pushed this to the GitGitGadget PR.
Thanks,
Dscho
