Re: [PATCH] git-am: indicate where a failed patch is to be found.
- From
- Paul Gortmaker <paul.gortmaker@windriver.com>
- Date
- Jul 13, 2012, 17:40 UTC
- Message-ID
- <50005D8E.1020407@windriver.com>
- In-Reply-To
- <7v629sbvh8.fsf@alter.siamese.dyndns.org>
On 12-07-12 04:00 PM, Junio C Hamano wrote:
Show 24 quoted lines
> Paul Gortmaker <paul.gortmaker@windriver.com> writes:
>
>>>>> This is _NOT_ fine, especially if you suggest "patch" the user may
>>>>> not have, and more importantly does not have a clue why "git apply"
>>>>> rejected it ("am" does _not_ use "patch" at all).
>>>>
>>>> I'm not 100% sure I'm following what part here is not OK. If you
>>>> can help me understand that, I'll respin the change accordingly.
>>>
>>> Do not ever mention "patch -p1". It is not the command that "git
>>> am" uses, and it is not what detected the breakage in the patch.
>>
>> This may be true, but it _is_ the command that I (and others) have
>> defaulted to using, if for no other reason than ignorance.
>>>
>>> The command to guide the user to is "git apply".
>>
>> OK. But I don't see a "--dry-run" equivalent -- and "git apply --check"
>> just gives me a repeat of the same fail messages that "git am" did.
>>
>> With "patch -p1 --dry-run" I get information that immediately
>> lets me see whether the patch is viable or not.
>
> What do you mean by "viable"? Sorry, that description was a bit context free. Two typical cases:
1) applying a series of commits (e.g. preempt RT feature) to a newer baseline. Some of those commits may have been upstreamed and now present in mainline. The "git am" failure doesn't really hint that "already applied" may be the case -- e.g. consider and compare the output when we extract and then intentionally try to re-apply something already in tree, created with:
------------- $git format-patch 50fb31cf~..50fb31cf 0001-tty-hvc_opal-Fix-debug-function-name.patch -------------
With "git am": -------------------------- $git am 0001-tty-hvc_opal-Fix-debug-function-name.patch Applying: tty/hvc_opal: Fix debug function name error: patch failed: drivers/tty/hvc/hvc_opal.c:401 error: drivers/tty/hvc/hvc_opal.c: patch does not apply Patch failed at 0001 tty/hvc_opal: Fix debug function name When you have resolved this problem run "git am --resolved". If you would prefer to skip this patch, instead run "git am --skip". To restore the original branch and stop patching run "git am --abort". ---------------------------
...versus
--------------------------- $patch -p1 --dry-run < 0001-tty-hvc_opal-Fix-debug-function-name.patch patching file drivers/tty/hvc/hvc_opal.c Reversed (or previously applied) patch detected! Assume -R? [n] Apply anyway? [n] Skipping patch. 1 out of 1 hunk ignored -- saving rejects to file drivers/tty/hvc/hvc_opal.c.rej ---------------------------
...versus
--------------------------- $git apply -p1 0001-tty-hvc_opal-Fix-debug-function-name.patch error: patch failed: drivers/tty/hvc/hvc_opal.c:401 error: drivers/tty/hvc/hvc_opal.c: patch does not apply ---------------------------
Maybe there is an easy way to teach git am/apply to detect "previously applied" in a way similar to patch? The closest I could come to that was "git apply --check -R ..." and seeing what it said (or didn't say).
2) In maintaining linux stable releases (esp older ones), the dry-run output, if say it says something like 23/30 chunks failed, it tells me that the underlying baseline has probably changed too much for a simple backport. But if only 1/30 chunks fail or similar, I'll simply proceed since the backport is viable and likely trivial.
Paul. --
Show 9 quoted lines
> > Independent from the answer to that question... > > Running "git apply -p1" would by definition give you the same > failure without --dry-run (because you know it already failed), no? > Then you could ask for rejects or attempt to apply with reduced > contexts to "git apply" all without having to say --dry-run, as > unapplicable change will not be applied. >