git reset respect remote repo (make git idiot proof)

git reset respect remote repo (make git idiot proof)

[Geoffrey De Smet]

Suppose this case:

git clone .../blessedRepo.git
// do changes
git commit -m"bad1"
// do changes
git commit -m"bad2"
git reset --hard HEAD^4 // Why does it let me do this?

// I just "broke" my local repository, because if I continue

// do changes
git commit -m"good1"
git push origin master // fails because the history disrespects the 
remote repo's history

The following commands are ok to do (because I have 2 unpushed commits):
  git reset --hard^1
  git reset --hard^2
but these are not and should be prevented (unless forced):
  git reset --hard^3
  git reset --hard^4


Is there any way to make git idiot proof by enabling that the local repo 
should always respect the history of the remote repo (unless forced)?
Is there any way to make this a default for anyone who clones our 
blessed repo?
No one that clones our blessed repo wants to come into the situation 
above. And if they do, they can always force it.

Re: git reset respect remote repo (make git idiot proof)

[Ramkumar Ramachandra]

Hi Geoffrey,

Geoffrey De Smet wrote:
> [...]
> The following commands are ok to do (because I have 2 unpushed commits):
>  git reset --hard^1
>  git reset --hard^2
> but these are not and should be prevented (unless forced):
>  git reset --hard^3
>  git reset --hard^4
>
>
> Is there any way to make git idiot proof by enabling that the local repo
> should always respect the history of the remote repo (unless forced)?
> Is there any way to make this a default for anyone who clones our blessed
> repo?
> No one that clones our blessed repo wants to come into the situation above.
> And if they do, they can always force it.

This makes little sense.
Which remote?  What if I have multiple remotes?  Which branch? (Many
of my branches are behind `master`).  What if I want different
histories on different remotes?  What about more advanced operations
which implicitly 'reset' like rebase?  What if I want to rewrite
history?

Ram

Re: git reset respect remote repo (make git idiot proof)

[Geoffrey De Smet]

Op 03-10-12 16:59, Ramkumar Ramachandra schreef:
> Hi Geoffrey,
>
> Geoffrey De Smet wrote:
>> [...]
>> The following commands are ok to do (because I have 2 unpushed commits):
>>   git reset --hard^1
>>   git reset --hard^2
>> but these are not and should be prevented (unless forced):
>>   git reset --hard^3
>>   git reset --hard^4
>>
>>
>> Is there any way to make git idiot proof by enabling that the local repo
>> should always respect the history of the remote repo (unless forced)?
>> Is there any way to make this a default for anyone who clones our 
>> blessed
>> repo?
>> No one that clones our blessed repo wants to come into the situation 
>> above.
>> And if they do, they can always force it.
> This makes little sense.
> Which remote?
To all remotes which have a relationship to this repo with the 
-respectRemote flag.
Normally, only the blessed remote will have this.
> What if I have multiple remotes?  Which branch? (Many
> of my branches are behind `master`).
Everytime a branch merges or rebases with a remote repository, it's 
flags the last commit of that remote repository as the pointOfNoReset 
commit.
If local branches merge or rebase with a local branch, the 
pointOfNoReset commit is transitively applied (only the last one wins).
git reset will fail to reset beyond the pointOfNoReset commit, unless 
forced.

Branches that are behind master, will have a pointOfNoReset commit in 
their history, if master goes forward afterwards, that won't affect 
those branches, not until they are merged.
>    What if I want different
> histories on different remotes?
Don't use the -respectRemote flag in the relationship between those 2 
repo's.
>   What about more advanced operations
> which implicitly 'reset' like rebase?
Them too. All operations would need to follow the -respectRemote flag's 
limitations, unless forced.
>    What if I want to rewrite
> history?
Don't use the -respectRemote flag in the relationship between this repo 
and any other repo.
Or force it.
>
> Ram

Re: git reset respect remote repo (make git idiot proof)

[Phil Hord]

On Wed, Oct 3, 2012 at 10:49 AM, Geoffrey De Smet
<ge0ffrey.spam@gmail.com> wrote:
> Suppose this case:
>
> git clone .../blessedRepo.git
> // do changes
> git commit -m"bad1"
> // do changes
> git commit -m"bad2"
> git reset --hard HEAD^4 // Why does it let me do this?
>
> // I just "broke" my local repository, because if I continue
>
> // do changes
> git commit -m"good1"
> git push origin master // fails because the history disrespects the remote
> repo's history
>
> The following commands are ok to do (because I have 2 unpushed commits):
>  git reset --hard^1
>  git reset --hard^2
> but these are not and should be prevented (unless forced):
>  git reset --hard^3
>  git reset --hard^4
>
>
> Is there any way to make git idiot proof by enabling that the local repo
> should always respect the history of the remote repo (unless forced)?
> Is there any way to make this a default for anyone who clones our blessed
> repo?

I suppose if we go down this path we must also prevent users from
having any local branches whose names match those used on the remote
unless the remote branches are also ancestors of our local branch.
But then we may get into trouble when we pull new branches which now
conflict but previously did not.

I'm afraid this is a Pandora's box of woes.

But I feel your pain.  I think the solution lies in relegating 'reset'
to the plumbing or the power-user realm of commands since I feel it is
quite overloaded and sometimes dangerous.  There was a thread some
months back heading in this direction, but I failed to keep it going.

    http://comments.gmane.org/gmane.comp.version-control.git/185825


Phil

Re: git reset respect remote repo (make git idiot proof)

[Andreas Schwab]

Geoffrey De Smet <ge0ffrey.spam@gmail.com> writes:

> Suppose this case:
>
> git clone .../blessedRepo.git
> // do changes
> git commit -m"bad1"
> // do changes
> git commit -m"bad2"
> git reset --hard HEAD^4 // Why does it let me do this?

Because there is nothing wrong with that.

> // I just "broke" my local repository, because if I continue

No you didn't.

> // do changes
> git commit -m"good1"
> git push origin master // fails because the history disrespects the remote
> repo's history

You may just as well want to push it to a different branch (or even a
different repository).

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: git reset respect remote repo (make git idiot proof)

[Geoffrey De Smet]

Op 03-10-12 18:52, Andreas Schwab schreef:
> Geoffrey De Smet <ge0ffrey.spam@gmail.com> writes:
>
>> Suppose this case:
>>
>> git clone .../blessedRepo.git
>> // do changes
>> git commit -m"bad1"
>> // do changes
>> git commit -m"bad2"
>> git reset --hard HEAD^4 // Why does it let me do this?
> Because there is nothing wrong with that.
>
>> // I just "broke" my local repository, because if I continue
> No you didn't.
>
>> // do changes
>> git commit -m"good1"
>> git push origin master // fails because the history disrespects the remote
>> repo's history
> You may just as well want to push it to a different branch (or even a
> different repository).
In most cases (probably more than 90%?), the developer will want to get 
his changes into the remote branch where it came from.

What do you think of the -respectRepository flag idea? If you want to 
push to different branches/repo's you can not use it, turn it off or 
-force those commands.

A remote repository can be optionally flagged with -respectRepository.
That means that git should prevent the user from making local changes in 
the history that will prevent a normal push to that remote repository.

If a remote repository is flagged as such, git keeps track of a 
"pointOfNoReset" commit:
Every time a branch merges or rebases with a remote repository, it's 
flags the last commit of that remote repository as the pointOfNoReset 
commit.
If local branches merge or rebase with a local branch, the 
pointOfNoReset commit is transitively applied (only the last one wins).
git reset will fail to reset beyond the pointOfNoReset commit, unless 
forced.
git rebase and other git commands will also fail accordingly, unless forced.

>
> Andreas.
>

Re: git reset respect remote repo (make git idiot proof)

[Geoffrey De Smet]

Op 03-10-12 18:40, Phil Hord schreef:
> But I feel your pain.  I think the solution lies in relegating 'reset'
> to the plumbing or the power-user realm of commands since I feel it is
> quite overloaded and sometimes dangerous.  There was a thread some
> months back heading in this direction, but I failed to keep it going.
>
>      http://comments.gmane.org/gmane.comp.version-control.git/185825

I personally use git reset a lot:
- Try an experiment
- Commit a few commits as the experiment progresses
- figure out that the experiment is a dead end
- git reset all those _local_ commits

The point is: they are local commits, so no harm done.
But there's nothing preventing me from resetting pushed commits too, 
which would mean harm.

Re: git reset respect remote repo (make git idiot proof)

[Junio C Hamano]

Geoffrey De Smet <ge0ffrey.spam@gmail.com> writes:

> Op 03-10-12 18:40, Phil Hord schreef:
>> But I feel your pain.  I think the solution lies in relegating 'reset'
>> to the plumbing or the power-user realm of commands since I feel it is
>> quite overloaded and sometimes dangerous.  There was a thread some
>> months back heading in this direction, but I failed to keep it going.
>>
>>      http://comments.gmane.org/gmane.comp.version-control.git/185825
>
> I personally use git reset a lot:
> - Try an experiment
> - Commit a few commits as the experiment progresses
> - figure out that the experiment is a dead end
> - git reset all those _local_ commits
>
> The point is: they are local commits, so no harm done.
> But there's nothing preventing me from resetting pushed commits too,
> which would mean harm.

Even if you reset your local branch beyond the point you pushed out,
no harm is caused, as "git push" will catch that mistake, e.g.

	: on 'master' that integrates with 'master' at remote
	$ git reset --hard HEAD~4
        : work work work and commit commit commit
        $ git push origin master
        ... will result in refusal due to non-fast-forward

And then you can recover from it easily; one workflow may go like
this:

	: update refs/remotes/origin/master, among other things
	$ git fetch origin
        : recover the "work work ... commit commit" part
        $ git rebase origin/master

Another thing we could think about doing is to warn at the point you
reset your head away.  The above "reset --hard HEAD~4", before doing
what it was told to do, could perform:

	git rev-list HEAD~4..HEAD

(replace "HEAD~4" with whereever you are attempting to go) and see
if any of the listed commits is an ancestor of @{upstream} of the
current branch.  And if that is true, then your updated "reset" can
issue a warning, just like "git checkout branchname" to leave the
detached HEAD state gives you a friendly warning.

Re: git reset respect remote repo (make git idiot proof)

[Dirk Heinrichs]

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Am Donnerstag 04 Oktober 2012, 10:59:36 schrieb Geoffrey De Smet:

> I personally use git reset a lot:
> - Try an experiment
> - Commit a few commits as the experiment progresses
> - figure out that the experiment is a dead end
> - git reset all those local commits

Hmm, what if you do your experiments on a dedicated branch? Branch deletion is 
"push-save", isn't it?

Bye...

	Dirk
-- 
Dirk Heinrichs <dirk.heinrichs@altum.de>
Tel: +49 (0)2471 209385 | Mobil: +49 (0)176 34473913
GPG Public Key C2E467BB | Jabber: dirk.heinrichs@altum.de

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