[PATCH] import: abort instead of crashing when copy source does not exist (issue5375)

Ryan McElroy rm at fb.com
Sun Oct 9 07:35:08 EDT 2016


On 10/8/2016 11:48 PM, Pierre-Yves David wrote:
>
>
> On 10/08/2016 07:06 PM, Mads Kiilerich wrote:
>> On 10/08/2016 06:11 PM, Ryan McElroy wrote:
>>> # HG changeset patch
>>> # User Ryan McElroy <rmcelroy at fb.com>
>>> # Date 1475929618 25200
>>> #      Sat Oct 08 05:26:58 2016 -0700
>>> # Node ID 961569a2cbeebfd54c9369c6e36d03d4938aef38
>>> # Parent  dbcef8918bbdd8a64d9f79a37bcfa284a26f3a39
>>> import: abort instead of crashing when copy source does not exist
>>> (issue5375)
>>>
>>> Previously, when a patch contained a move or copy from a source that
>>> did not
>>> exist, `hg import` would crash. This patch changes import to raise a
>>> PatchError
>>> with an explanantion of what is wrong with the patch to avoid the
>>> stack trace
>>> and bad user experience.
>>>
>>> diff --git a/mercurial/patch.py b/mercurial/patch.py
>>> --- a/mercurial/patch.py
>>> +++ b/mercurial/patch.py
>>> @@ -1952,8 +1952,10 @@ def _applydiff(ui, fp, patcher, backend,
>>>                   data, mode = None, None
>>>                   if gp.op in ('RENAME', 'COPY'):
>>>                       data, mode = store.getfile(gp.oldpath)[:2]
>>> -                    # FIXME: failing getfile has never been handled 
>>> here
>>> -                    assert data is not None
>>> +                    if data is None:
>>> +                        # This means that the old path does not exist
>>> +                        raise PatchError(_("source file '%s' does not
>>> exist")
>>> +                                           % gp.oldpath)
>>>                   if gp.mode:
>>>                       mode = gp.mode
>>>                       if gp.op == 'ADD':
>>> diff --git a/tests/test-import.t b/tests/test-import.t
>>> --- a/tests/test-import.t
>>> +++ b/tests/test-import.t
>>> @@ -1793,3 +1793,13 @@ repository when file not found for patch
>>>     1 out of 1 hunks FAILED -- saving rejects to file file1.rej
>>>     abort: patch failed to apply
>>>     [255]
>>> +
>>> +test import crash (issue5375)
>>> +  $ cd ..
>>> +  $ hg init repo
>>> +  $ cd repo
>>> +  $ printf "diff --git a/a b/b\nrename from a\nrename to b" | hg
>>> import -
>>> +  applying patch from stdin
>>> +  a not tracked!
>>> +  abort: source file 'a' does not exist
>>> +  [255]
>>
>> Hmm.
>>
>> For a patch modifying a non-existing file we already get:
>>
>>
>> unable to find 'f' for patching
>> 1 out of 1 hunks FAILED -- saving rejects to file f.rej
>> patch failed, unable to continue (try -v)
>> patch failed, rejects left in working directory
>>
>> $ cat f.rej
>> --- f
>> +++ f
>> @@ -1,1 +1,2 @@
>>
>> +f
>>
>> In the tested case, I would thus also expect it to leave a .rej file
>> with the failing rename "hunk" while applying the rest of the patch
>> (even though a pure rename arguably *doesn't* have any hunks).
>>
>> BUT the logic around this check seems wrong. A rename or copy of a
>> missing file should be handled exactly the same, no matter if it is a
>> bare rename/copy or if it also modifies the file (= has a first hunk).
>>
>> I don't know if it is better to give a not-entirely-correct abort than
>> to fail with an assertion error, but I think it still deserves a
>> FIXME/TODO.
>
> +1 we should keep the same erro flow than for other patch error 
> (especially because I'm not sure how --partial deal with this patch.
>
>> (The iterhunks docstring seems wrong, for example regarding 'file'
>> entries and firsthunk. Let's go find pmezard!)
>
> TGVs for Brest leave from Gare Montparnasse every hour.
>
> Cheers,
>

1/ I can't tell if this is actually still queued or not because of the 
follow-up comments. Do I need to send a V2 that keeps the TODO/FIXME line?

2/ I think not crashing is a very good start. I'm okay opening a 
follow-up issue to move on to even better behavior, but not crashing 
seems imperative.





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