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lock_ref_for_update(): make error handling more uniform

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To aid the effort, extract a new function, check_old_oid(), and use it
in the two places where the read value of the reference has to be
checked against update->old_sha1.

Update tests to reflect the improvements.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Michael Haggerty
2016-06-07 09:29:23 +02:00
committed by Junio C Hamano
parent c5119dcf49
commit e3f510393c
2 changed files with 49 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
refs/files-backend.c
View File

@ -3388,6 +3388,38 @@ static const char *original_update_refname(struct ref_update *update)
return update->refname;
}
/*
* Check whether the REF_HAVE_OLD and old_oid values stored in update
* are consistent with oid, which is the reference's current value. If
* everything is OK, return 0; otherwise, write an error message to
* err and return -1.
*/
static int check_old_oid(struct ref_update *update, struct object_id *oid,
struct strbuf *err)
{
if (!(update->flags & REF_HAVE_OLD) ||
!hashcmp(oid->hash, update->old_sha1))
return 0;
if (is_null_sha1(update->old_sha1))
strbuf_addf(err, "cannot lock ref '%s': "
"reference already exists",
original_update_refname(update));
else if (is_null_oid(oid))
strbuf_addf(err, "cannot lock ref '%s': "
"reference is missing but expected %s",
original_update_refname(update),
sha1_to_hex(update->old_sha1));
else
strbuf_addf(err, "cannot lock ref '%s': "
"is at %s but expected %s",
original_update_refname(update),
oid_to_hex(oid),
sha1_to_hex(update->old_sha1));
return -1;
}
/*
* Prepare for carrying out update:
* - Lock the reference referred to by update.
@ -3433,7 +3465,7 @@ static int lock_ref_for_update(struct ref_update *update,
reason = strbuf_detach(err, NULL);
strbuf_addf(err, "cannot lock ref '%s': %s",
update->refname, reason);
original_update_refname(update), reason);
free(reason);
return ret;
}
@ -3447,28 +3479,17 @@ static int lock_ref_for_update(struct ref_update *update,
* the transaction, so we have to read it here
* to record and possibly check old_sha1:
*/
if (read_ref_full(update->refname,
mustexist ? RESOLVE_REF_READING : 0,
if (read_ref_full(update->refname, 0,
lock->old_oid.hash, NULL)) {
if (update->flags & REF_HAVE_OLD) {
strbuf_addf(err, "cannot lock ref '%s': "
"can't resolve old value",
update->refname);
return TRANSACTION_GENERIC_ERROR;
} else {
hashclr(lock->old_oid.hash);
"error reading reference",
original_update_refname(update));
return -1;
}
}
if ((update->flags & REF_HAVE_OLD) &&
hashcmp(lock->old_oid.hash, update->old_sha1)) {
strbuf_addf(err, "cannot lock ref '%s': "
"is at %s but expected %s",
update->refname,
sha1_to_hex(lock->old_oid.hash),
sha1_to_hex(update->old_sha1));
} else if (check_old_oid(update, &lock->old_oid, err)) {
return TRANSACTION_GENERIC_ERROR;
}
} else {
/*
* Create a new update for the reference this
@ -3485,6 +3506,9 @@ static int lock_ref_for_update(struct ref_update *update,
} else {
struct ref_update *parent_update;
if (check_old_oid(update, &lock->old_oid, err))
return TRANSACTION_GENERIC_ERROR;
/*
* If this update is happening indirectly because of a
* symref update, record the old SHA-1 in the parent
@ -3495,20 +3519,6 @@ static int lock_ref_for_update(struct ref_update *update,
parent_update = parent_update->parent_update) {
oidcpy(&parent_update->lock->old_oid, &lock->old_oid);
}
if ((update->flags & REF_HAVE_OLD) &&
hashcmp(lock->old_oid.hash, update->old_sha1)) {
if (is_null_sha1(update->old_sha1))
strbuf_addf(err, "cannot lock ref '%s': reference already exists",
original_update_refname(update));
else
strbuf_addf(err, "cannot lock ref '%s': is at %s but expected %s",
original_update_refname(update),
sha1_to_hex(lock->old_oid.hash),
sha1_to_hex(update->old_sha1));
return TRANSACTION_GENERIC_ERROR;
}
}
if ((update->flags & REF_HAVE_NEW) &&
@ -3530,7 +3540,7 @@ static int lock_ref_for_update(struct ref_update *update,
*/
update->lock = NULL;
strbuf_addf(err,
"cannot update the ref '%s': %s",
"cannot update ref '%s': %s",
update->refname, write_err);
free(write_err);
return TRANSACTION_GENERIC_ERROR;