This patch series is based on mhagger/ref-transactions and expands on the
transaction API. It converts all external (outside of refs.c) callers to
use the transaction API for any writes.
This makes most of the ref updates to become atomic when there are failures
locking or writing to a ref.
Version 5:
- Reword commit messages for having _create/_delete/_update returning
success/failure. There are no conditions yet that return an error from
these failures but there will be in the future. So we still check the
return from these functions in the callers in preparation for this.
- Don't leak memory by just passing a strbuf_detach() pointer to functions.
Use <obj>.buf and explicitely strbuf_release the data afterwards.
- Remove the function update_ref_lock.
- Remove the function update_ref_write.
- Track transaction status and die(BUG:) if we call _create/_delete/_update/
_commit for a transaction that is not OPEN.
Version 4:
- Rename patch series from "Use ref transactions from most callers" to
"Use ref transactions for all ref updates".
- Convert all external ref writes to use transactions and make write_ref_sha1
and lock_ref_sha1 static functions.
- Change the ref commit and free handling so we no longer pass pointer to
pointer to _commit. _commit no longer frees the transaction. The caller
MUST call _free itself.
- Change _commit to take a strbuf pointer instead of a char* for error
reporting back to the caller.
- Re-add the walker patch after fixing it.
Version 3:
- Remove the walker patch for now. Walker needs more complex solution
so defer it until the basics are done.
- Remove the onerr argument to ref_transaction_commit(). All callers
that need to die() on error now have to do this explicitely.
- Pass an error string from ref_transaction_commit() back to the callers
so that they can craft a nice error message upon failures.
- Make ref_transaction_rollback() accept NULL as argument.
- Change ref_transaction_commit() to take a pointer to pointer argument for
the transaction and have it clear the callers pointer to NULL when
invoked. This allows for much nicer handling of transaction rollback on
failure.
Version 2:
- Add a patch to ref_transaction_commit to make it honor onerr even if the
error triggered in ref_Transaction_commit itself rather than in a call
to other functions (that already honor onerr).
- Add a patch to make the update_ref() helper function use transactions
internally.
- Change ref_transaction_update to die() instead of error() if we pass
if a NULL old_sha1 but have have_old == true.
- Change ref_transaction_create to die() instead of error() if new_sha1
is false but we pass it a null_sha1.
- Change ref_transaction_delete die() instead of error() if we pass
if a NULL old_sha1 but have have_old == true.
- Change several places to do if(!transaction || ref_transaction_update()
|| ref_Transaction_commit()) die(generic-message) instead of checking each
step separately and having a different message for each failure.
Most users are likely not interested in what step of the transaction
failed and only whether it failed or not.
- Change commit.c to only pass a pointer to ref_transaction_update
iff current_head is non-NULL.
The previous patch used to compute a garbage pointer for
current_head->object.sha1 and relied on the fact that ref_transaction_update
would not try to dereference this pointer if !!current_head was 0.
- Updated commit message for the walker_fetch change to try to justify why
the change in locking semantics should not be harmful.
Ronnie Sahlberg (30):
refs.c: constify the sha arguments for
ref_transaction_create|delete|update
refs.c: allow passing NULL to ref_transaction_free
refs.c: add a strbuf argument to ref_transaction_commit for error
logging
refs.c: make ref_update_reject_duplicates take a strbuf argument for
errors
update-ref.c: log transaction error from the update_ref
refs.c: make update_ref_write update a strbuf on failure
refs.c: remove the onerr argument to ref_transaction_commit
refs.c: change ref_transaction_update() to do error checking and
return status
refs.c: change ref_transaction_create to do error checking and return
status
refs.c: ref_transaction_delete to check for error and return status
tag.c: use ref transactions when doing updates
replace.c: use the ref transaction functions for updates
commit.c: use ref transactions for updates
sequencer.c: use ref transactions for all ref updates
fast-import.c: change update_branch to use ref transactions
branch.c: use ref transaction for all ref updates
refs.c: change update_ref to use a transaction
refs.c: free the transaction before returning when number of updates
is 0
refs.c: ref_transaction_commit should not free the transaction
fetch.c: clear errno before calling functions that might set it
fetch.c: change s_update_ref to use a ref transaction
fetch.c: use a single ref transaction for all ref updates
receive-pack.c: use a reference transaction for updating the refs
fast-import.c: use a ref transaction when dumping tags
walker.c: use ref transaction for ref updates
refs.c: make write_ref_sha1 static
refs.c: make lock_ref_sha1 static
refs.c: add transaction.status and track OPEN/CLOSED/ERROR
refs.c: remove the update_ref_lock function
refs.c: remove the update_ref_write function
branch.c | 31 ++++----
builtin/commit.c | 24 +++---
builtin/fetch.c | 35 ++++-----
builtin/receive-pack.c | 20 ++---
builtin/replace.c | 15 ++--
builtin/tag.c | 15 ++--
builtin/update-ref.c | 29 +++++---
fast-import.c | 38 ++++++----
refs.c | 193 +++++++++++++++++++++++++++++--------------------
refs.h | 45 ++++++------
sequencer.c | 24 ++++--
walker.c | 51 ++++++-------
12 files changed, 297 insertions(+), 223 deletions(-)
--
1.9.1.532.gf8485a6
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