Improve hint for diverging branches.

[perk11]

I have seen a lot of developers not know what to do when they try
to do a git pull on a master branch with the intention of updating
that branch to the latest version, but see an error about branches
diverging because they accidentally committed their changes to
that branch. They then spend their time resolving conflicts and
still not getting the intended result. The suggestion to do a hard
reset should be something that helps in this situation.

I'm not sure if a new config option needs to be created as
technically these are two different advice now.
I'm also not sure if "refs/remotes" part of the refspec is necessary,
that is what I found the functions in pull.c are returning.
I think "upstream/branch-name" should be the same thing, but kept it
as is ( git reset --hard refs/remotes/upstream/branch-name) for now.
Please feel free to chime in.

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[gitgitgadget-git]

There are issues in commit 23fa109:
Improve hint for diverging branches.
Lines in the body of the commit messages should be wrapped between 60 and 76 characters.
Indented lines, and lines without whitespace, are exempt

[gitgitgadget-git]

There are issues in commit 40aa49a:
Improve hint for diverging branches.
Lines in the body of the commit messages should be wrapped between 60 and 76 characters.
Indented lines, and lines without whitespace, are exempt

[dscho]

/allow

[gitgitgadget-git]

User perk11 is now allowed to use GitGitGadget.

[perk11]

/preview

[gitgitgadget-git]

Preview email sent as pull.1570.git.git.1693858078020.gitgitgadget@gmail.com

[perk11]

/preview

[gitgitgadget-git]

Preview email sent as pull.1570.git.git.1693858939372.gitgitgadget@gmail.com

[perk11]

/preview

[gitgitgadget-git]

Preview email sent as pull.1570.git.git.1693859432738.gitgitgadget@gmail.com

[perk11]

/submit

[gitgitgadget-git]

Submitted as pull.1570.git.git.1693861162353.gitgitgadget@gmail.com

To fetch this version into FETCH_HEAD:

git fetch https://github.com/gitgitgadget/git/ pr-git-1570/perk11/diverging-advice-improvements-v1

To fetch this version to local tag pr-git-1570/perk11/diverging-advice-improvements-v1:

git fetch --no-tags https://github.com/gitgitgadget/git/ tag pr-git-1570/perk11/diverging-advice-improvements-v1

[gitgitgadget-git]

On the Git mailing list, Junio C Hamano wrote (reply to this):

"Konstantin Pereiaslov via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> From: Konstantin Pereiaslov <perk11@perk11.info>
>
> Added a description of what the offered options will do and for pull
> also offered a 3rd option during a pull - a hard reset.
> This option should be helpful for the new users that accidentally
> committed into the wrong branch which is a scenario I saw very
> often.

cf. Documentation/SubmittingPatches:[[describe-changes]]

> The resulting tooltip looks like this for pull:
>
> hint: Diverging branches can't be fast-forwarded.
> Consider the following options:

We do not give "hint:" prefix to this line???

> hint:
> hint: To merge remote changes into your branch:
> hint:   git merge --no-ff
> hint:
> hint: To apply your changes on top of remote changes:
> hint:   git rebase

Hmph, "apply" -> "replay" perhaps?

> hint: To discard your local changes and apply the remote changes:

Here "apply" is definitely a misnomer.  Nothing is applied; you just
discard your work and adopt (or "accept") the state of the remote as
a whole.

> hint:   git reset --hard refs/remotes/upstream/branch-name
> hint:
> hint: Disable this message with "git config advice.diverging false"

OK.

Overall, "... looks like this" should be shown a bit indented so
that the example stands out from the text that explains the example.

> There is some danger because it's semi-destructive, but so are
> other options offered if user doesn't know the commands to
> revert back.

Sorry, but I do not quite understand what you want to say here.

> @@ -1112,8 +1126,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
>  
>  	/* ff-only takes precedence over rebase */
>  	if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
> -		if (divergent)
> -			die_ff_impossible();
> +		if (divergent) {
> +			const char* pull_branch_spec = get_pull_branch(repo, *refspecs);

In this codebase, asterisk sticks to the variable/function
identifier, not types.

But more importantly, what guarantees your recomputation using
'*refspecs' here will match the result of the logic that computed
'divergent', which certainly would have already known what commit we
tried to fast-forward our branch to, and where that commit came
from?  We shouldn't be computing the same thing twice, and in
different ways; that is a sure way to introduce inconsistent
results.

> +			die_ff_impossible_during_pull(pull_branch_spec);
> +		}
>  		opt_rebase = REBASE_FALSE;
>  	}
>  	/* If no action specified and we can't fast forward, then warn. */
>
> base-commit: d814540bb75bbd2257f9a6bf59661a84fe8cf3cf

Thanks.

[gitgitgadget-git]

On the Git mailing list, Konstantin Pereiaslov wrote (reply to this):

Thank you, all good points. I will work on the wording
improvements based on your suggestions.

"Consider the following options:" should be on a new line and
get a "hint:" prefix, I will fix that.


As far as the danger to the user, I was talking about the fact that
the user doing "git reset --hard" is going to lose any uncommitted
work as well as any commits currently in the branch.

> "But more importantly, what guarantees your recomputation using
> '*refspecs' here will match the result of the logic that computed
> 'divergent', which certainly would have already known what commit we
> tried to fast-forward our branch to, and where that commit came
> from?  We shouldn't be computing the same thing twice, and in
> different ways; that is a sure way to introduce inconsistent
> results.

This makes sens, I did it this way because I wanted to get a remote and
branch name, not just hash id and it was difficult to get this information.
I will try to rework it so that it shares the code with the logic that determines
the divergence status.
Any tips on what's the best way to do that would be highly appreciated.

On 9/5/23 18:20, Junio C Hamano wrote:
> "Konstantin Pereiaslov via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
>
>> From: Konstantin Pereiaslov <perk11@perk11.info>
>>
>> Added a description of what the offered options will do and for pull
>> also offered a 3rd option during a pull - a hard reset.
>> This option should be helpful for the new users that accidentally
>> committed into the wrong branch which is a scenario I saw very
>> often.
> cf. Documentation/SubmittingPatches:[[describe-changes]]
>
>> The resulting tooltip looks like this for pull:
>>
>> hint: Diverging branches can't be fast-forwarded.
>> Consider the following options:
> We do not give "hint:" prefix to this line???
>
>> hint:
>> hint: To merge remote changes into your branch:
>> hint:   git merge --no-ff
>> hint:
>> hint: To apply your changes on top of remote changes:
>> hint:   git rebase
> Hmph, "apply" -> "replay" perhaps?
>
>> hint: To discard your local changes and apply the remote changes:
> Here "apply" is definitely a misnomer.  Nothing is applied; you just
> discard your work and adopt (or "accept") the state of the remote as
> a whole.
>
>> hint:   git reset --hard refs/remotes/upstream/branch-name
>> hint:
>> hint: Disable this message with "git config advice.diverging false"
> OK.
>
> Overall, "... looks like this" should be shown a bit indented so
> that the example stands out from the text that explains the example.
>
>> There is some danger because it's semi-destructive, but so are
>> other options offered if user doesn't know the commands to
>> revert back.
> Sorry, but I do not quite understand what you want to say here.
>
>> @@ -1112,8 +1126,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
>>   >>   	/* ff-only takes precedence over rebase */
>>   	if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
>> -		if (divergent)
>> -			die_ff_impossible();
>> +		if (divergent) {
>> +			const char* pull_branch_spec = get_pull_branch(repo, *refspecs);
> In this codebase, asterisk sticks to the variable/function
> identifier, not types.
>
> But more importantly, what guarantees your recomputation using
> '*refspecs' here will match the result of the logic that computed
> 'divergent', which certainly would have already known what commit we
> tried to fast-forward our branch to, and where that commit came
> from?  We shouldn't be computing the same thing twice, and in
> different ways; that is a sure way to introduce inconsistent
> results.
>
>> +			die_ff_impossible_during_pull(pull_branch_spec);
>> +		}
>>   		opt_rebase = REBASE_FALSE;
>>   	}
>>   	/* If no action specified and we can't fast forward, then warn. */
>>
>> base-commit: d814540bb75bbd2257f9a6bf59661a84fe8cf3cf
> Thanks.

[gitgitgadget-git]

On the Git mailing list, Konstantin Pereiaslov wrote (reply to this):

Thank you, all good points. I will work on the wording
improvements based on your suggestions.

"Consider the following options:" should be on a new line and
get a "hint:" prefix, I will fix that.


As far as the danger to the user, I was talking about the fact that
the user doing "git reset --hard" is going to lose any uncommitted
work as well as any commits currently in the branch.

> "But more importantly, what guarantees your recomputation using
> '*refspecs' here will match the result of the logic that computed
> 'divergent', which certainly would have already known what commit we
> tried to fast-forward our branch to, and where that commit came
> from?  We shouldn't be computing the same thing twice, and in
> different ways; that is a sure way to introduce inconsistent
> results.

This makes sens, I did it this way because I wanted to get a remote and
branch name, not just hash id and it was difficult to get this information.
I will try to rework it so that it shares the code with the logic that determines
the divergence status.
Any tips on what's the best way to do that would be highly appreciated.

On 9/5/23 18:20, Junio C Hamano wrote:
> "Konstantin Pereiaslov via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
>
>> From: Konstantin Pereiaslov <perk11@perk11.info>
>>
>> Added a description of what the offered options will do and for pull
>> also offered a 3rd option during a pull - a hard reset.
>> This option should be helpful for the new users that accidentally
>> committed into the wrong branch which is a scenario I saw very
>> often.
> cf. Documentation/SubmittingPatches:[[describe-changes]]
>
>> The resulting tooltip looks like this for pull:
>>
>> hint: Diverging branches can't be fast-forwarded.
>> Consider the following options:
> We do not give "hint:" prefix to this line???
>
>> hint:
>> hint: To merge remote changes into your branch:
>> hint:   git merge --no-ff
>> hint:
>> hint: To apply your changes on top of remote changes:
>> hint:   git rebase
> Hmph, "apply" -> "replay" perhaps?
>
>> hint: To discard your local changes and apply the remote changes:
> Here "apply" is definitely a misnomer.  Nothing is applied; you just
> discard your work and adopt (or "accept") the state of the remote as
> a whole.
>
>> hint:   git reset --hard refs/remotes/upstream/branch-name
>> hint:
>> hint: Disable this message with "git config advice.diverging false"
> OK.
>
> Overall, "... looks like this" should be shown a bit indented so
> that the example stands out from the text that explains the example.
>
>> There is some danger because it's semi-destructive, but so are
>> other options offered if user doesn't know the commands to
>> revert back.
> Sorry, but I do not quite understand what you want to say here.
>
>> @@ -1112,8 +1126,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
>>   >>   	/* ff-only takes precedence over rebase */
>>   	if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
>> -		if (divergent)
>> -			die_ff_impossible();
>> +		if (divergent) {
>> +			const char* pull_branch_spec = get_pull_branch(repo, *refspecs);
> In this codebase, asterisk sticks to the variable/function
> identifier, not types.
>
> But more importantly, what guarantees your recomputation using
> '*refspecs' here will match the result of the logic that computed
> 'divergent', which certainly would have already known what commit we
> tried to fast-forward our branch to, and where that commit came
> from?  We shouldn't be computing the same thing twice, and in
> different ways; that is a sure way to introduce inconsistent
> results.
>
>> +			die_ff_impossible_during_pull(pull_branch_spec);
>> +		}
>>   		opt_rebase = REBASE_FALSE;
>>   	}
>>   	/* If no action specified and we can't fast forward, then warn. */
>>
>> base-commit: d814540bb75bbd2257f9a6bf59661a84fe8cf3cf
> Thanks.
>