* How to find the commit that erase a change
@ 2019-10-09 2:28 wuzhouhui
2019-10-09 3:02 ` Junio C Hamano
0 siblings, 1 reply; 4+ messages in thread
From: wuzhouhui @ 2019-10-09 2:28 UTC (permalink / raw)
To: git; +Cc: cuifang
Hi,
I have a file which contains complicated change history. When I use
git log -p file
to see all changes made in this file, I found that a change disappeared
for no reason.
For example, I made following change in a commit:
@@ -2,3 +2,8 @@ int main(void)
{
printf("hello world");
}
+
+func(void)
+{
+ printf("a func");
+}
But when I open this file of latest version, I found the above change is
disappeared. So I decide use
git log -p file
to see which commit erase my change. But I doesn't see any commit which
contains changes like following:
@@ -2,8 +2,3 @@ int main(void)
{
printf("hello world");
}
-
-func(void)
-{
- printf("a func");
-}
So, how to find the commit that erase my change?
Thanks. Please use Reply-All when reply this email.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: How to find the commit that erase a change
2019-10-09 2:28 How to find the commit that erase a change wuzhouhui
@ 2019-10-09 3:02 ` Junio C Hamano
2019-10-09 3:51 ` wuzhouhui
0 siblings, 1 reply; 4+ messages in thread
From: Junio C Hamano @ 2019-10-09 3:02 UTC (permalink / raw)
To: wuzhouhui; +Cc: git, cuifang
wuzhouhui <wuzhouhui14@mails.ucas.ac.cn> writes:
> I have a file which contains complicated change history. When I use
> git log -p file
> to see all changes made in this file, I found that a change disappeared
> for no reason.
"git log [-p] <pathspec>" is not about seeing *all* changes made to
the path(s) that match the pathspec. Especially when your history
has merges, the command is to give you _one_ simplest explanation as
to how the contents of the path(s) came to be in the shape you see
in HEAD.
So for example, if you have a history like this (time flows from
left to right):
O-----A-----B----M-----N
\ /
\ /
X----Y
where A or B did *not* touch "file", X added a definition of func()
to "file", Y reverted the change X made to "file", M made a natural
merge between B and Y and N did not touch "file", "git log N file"
would not even show the existence of commits X or Y. In the larger
picture, at ancient time O, the file started without func(), and
none of the commits A, B, M or N felt the need to add it and as the
result, N does not need the unwanted func(). So "file's contents
are the same since O throughout the history reaching N" is given as
_one_ simplest explanation.
The "--full-history" option may help, though.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Re: How to find the commit that erase a change
2019-10-09 3:02 ` Junio C Hamano
@ 2019-10-09 3:51 ` wuzhouhui
2019-10-09 13:21 ` Derrick Stolee
0 siblings, 1 reply; 4+ messages in thread
From: wuzhouhui @ 2019-10-09 3:51 UTC (permalink / raw)
To: junio c hamano; +Cc: git, cuifang
> -----Original Messages-----
> From: "Junio C Hamano" <gitster@pobox.com>
> Sent Time: 2019-10-09 11:02:44 (Wednesday)
> To: wuzhouhui <wuzhouhui14@mails.ucas.ac.cn>
> Cc: git@vger.kernel.org, cuifang@sugon.com
> Subject: Re: How to find the commit that erase a change
>
> wuzhouhui <wuzhouhui14@mails.ucas.ac.cn> writes:
>
> > I have a file which contains complicated change history. When I use
> > git log -p file
> > to see all changes made in this file, I found that a change disappeared
> > for no reason.
>
> "git log [-p] <pathspec>" is not about seeing *all* changes made to
> the path(s) that match the pathspec. Especially when your history
> has merges, the command is to give you _one_ simplest explanation as
> to how the contents of the path(s) came to be in the shape you see
> in HEAD.
>
> So for example, if you have a history like this (time flows from
> left to right):
>
> O-----A-----B----M-----N
> \ /
> \ /
> X----Y
>
> where A or B did *not* touch "file", X added a definition of func()
> to "file", Y reverted the change X made to "file", M made a natural
> merge between B and Y and N did not touch "file", "git log N file"
> would not even show the existence of commits X or Y. In the larger
> picture, at ancient time O, the file started without func(), and
> none of the commits A, B, M or N felt the need to add it and as the
> result, N does not need the unwanted func(). So "file's contents
> are the same since O throughout the history reaching N" is given as
> _one_ simplest explanation.
>
> The "--full-history" option may help, though.
"--full-history" doesn't resolve my problem, but
git log -p -c file
does. I found that my change was erased in a merge commit.
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: How to find the commit that erase a change
2019-10-09 3:51 ` wuzhouhui
@ 2019-10-09 13:21 ` Derrick Stolee
0 siblings, 0 replies; 4+ messages in thread
From: Derrick Stolee @ 2019-10-09 13:21 UTC (permalink / raw)
To: wuzhouhui, junio c hamano; +Cc: git, cuifang
On 10/8/2019 11:51 PM, wuzhouhui wrote:
>> -----Original Messages-----
>> From: "Junio C Hamano" <gitster@pobox.com>
>> Sent Time: 2019-10-09 11:02:44 (Wednesday)
>> To: wuzhouhui <wuzhouhui14@mails.ucas.ac.cn>
>> Cc: git@vger.kernel.org, cuifang@sugon.com
>> Subject: Re: How to find the commit that erase a change
>>
>> wuzhouhui <wuzhouhui14@mails.ucas.ac.cn> writes:
>>
>>> I have a file which contains complicated change history. When I use
>>> git log -p file
>>> to see all changes made in this file, I found that a change disappeared
>>> for no reason.
>>
>> "git log [-p] <pathspec>" is not about seeing *all* changes made to
>> the path(s) that match the pathspec. Especially when your history
>> has merges, the command is to give you _one_ simplest explanation as
>> to how the contents of the path(s) came to be in the shape you see
>> in HEAD.
>>
>> So for example, if you have a history like this (time flows from
>> left to right):
>>
>> O-----A-----B----M-----N
>> \ /
>> \ /
>> X----Y
>>
>> where A or B did *not* touch "file", X added a definition of func()
>> to "file", Y reverted the change X made to "file", M made a natural
>> merge between B and Y and N did not touch "file", "git log N file"
>> would not even show the existence of commits X or Y. In the larger
>> picture, at ancient time O, the file started without func(), and
>> none of the commits A, B, M or N felt the need to add it and as the
>> result, N does not need the unwanted func(). So "file's contents
>> are the same since O throughout the history reaching N" is given as
>> _one_ simplest explanation.
>>
>> The "--full-history" option may help, though.
>
> "--full-history" doesn't resolve my problem, but
> git log -p -c file
> does. I found that my change was erased in a merge commit.
In these cases of erased merge commits, I find that
git log --simplify-merges -- file
works best for finding the merge responsible. Just the
--full-history option may include many extra merges (if you
work in a repo with many collaborators).
Thanks,
-Stolee
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-10-09 13:21 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-10-09 2:28 How to find the commit that erase a change wuzhouhui
2019-10-09 3:02 ` Junio C Hamano
2019-10-09 3:51 ` wuzhouhui
2019-10-09 13:21 ` Derrick Stolee
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