threads / patch / 39220

patchbranch: fix funny-sounding error message

Subject: [PATCH] branch: fix funny-sounding error message

## tl;dr

5 messages between May 2, 2015 and May 5, 2015. Diffs are folded; open one to read it.

replies: 4people: 3as markdown or json

Alex Henrie· May 2, 2015, 03:12 UTC · lore
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
---
 builtin/branch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to builtin/branch.c +1 −1
diff --git a/builtin/branch.c b/builtin/branch.c
index 1d15037..c0b4bae 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -972,7 +972,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 		if (!branch) {
 			if (!argc || !strcmp(argv[0], "HEAD"))
-				die(_("could not set upstream of HEAD to %s when "
+				die(_("could not set upstream of HEAD to %s because "
 				      "it does not point to any branch."),
 				    new_upstream);
 			die(_("no such branch '%s'"), argv[0]);
-- 
2.3.7
Junio C Hamano· May 3, 2015, 23:54 UTC · re: Alex Henrie · lore

Re: [PATCH] branch: fix funny-sounding error message

Alex Henrie <alexhenrie24@gmail.com> writes:
Show 18 quoted lines
> Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
> ---
>  builtin/branch.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/builtin/branch.c b/builtin/branch.c
> index 1d15037..c0b4bae 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> @@ -972,7 +972,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
>  
>  		if (!branch) {
>  			if (!argc || !strcmp(argv[0], "HEAD"))
> -				die(_("could not set upstream of HEAD to %s when "
> +				die(_("could not set upstream of HEAD to %s because "
>  				      "it does not point to any branch."),
>  				    new_upstream);
>  			die(_("no such branch '%s'"), argv[0]);
Thanks.

To me neither sounds so funny, but both sound somewhat awkward, primarily because it is unclear in the first reading what "it" in "it does not point at any branch" refers to.

Perhaps if you explain in the log message to illustrate why you found it funny (and the update text is not), it might help, e.g.

    "git branch", ran with <this and that options>, when the current
    branch is <in what state>, dies with
    	fatal: could not set upstream of HEAD to frotz when it does not
    	point to any branch.
    which is funny <because of such and such reasons>.  Saying "because"
    makes it <better beause of such and such reasons>.

I suspect that this message is about a nonsense attempt to set an upstream for a detached HEAD perhaps? Then

    fatal: cannot set upstream for a detached HEAD

may be shorter and more directly points at the root cause of the error?

Alex Henrie· May 5, 2015, 19:42 UTC · re: Junio C Hamano · lore

Re: [PATCH] branch: fix funny-sounding error message

2015-05-03 17:54 GMT-06:00 Junio C Hamano <gitster@pobox.com>:
Show 46 quoted lines
> Alex Henrie <alexhenrie24@gmail.com> writes:
>
>> Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
>> ---
>>  builtin/branch.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/builtin/branch.c b/builtin/branch.c
>> index 1d15037..c0b4bae 100644
>> --- a/builtin/branch.c
>> +++ b/builtin/branch.c
>> @@ -972,7 +972,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
>>
>>               if (!branch) {
>>                       if (!argc || !strcmp(argv[0], "HEAD"))
>> -                             die(_("could not set upstream of HEAD to %s when "
>> +                             die(_("could not set upstream of HEAD to %s because "
>>                                     "it does not point to any branch."),
>>                                   new_upstream);
>>                       die(_("no such branch '%s'"), argv[0]);
>
> Thanks.
>
> To me neither sounds so funny, but both sound somewhat awkward,
> primarily because it is unclear in the first reading what "it" in
> "it does not point at any branch" refers to.
>
> Perhaps if you explain in the log message to illustrate why you
> found it funny (and the update text is not), it might help, e.g.
>
>     "git branch", ran with <this and that options>, when the current
>     branch is <in what state>, dies with
>
>         fatal: could not set upstream of HEAD to frotz when it does not
>         point to any branch.
>
>     which is funny <because of such and such reasons>.  Saying "because"
>     makes it <better beause of such and such reasons>.
>
> I suspect that this message is about a nonsense attempt to set an
> upstream for a detached HEAD perhaps?  Then
>
>     fatal: cannot set upstream for a detached HEAD
>
> may be shorter and more directly points at the root cause of the
> error?

I don't really understand what this code is doing. It just sounds funny to use "when" to join a phrase in the past tense with a phrase in the present tense.

This error message can be triggered by running `git branch --set-upstream-to=origin/master` from a detached head. But if running from a detached head is the only way to trigger the error message, why does the code use strcmp instead of if (detached) { ... } as other code in that function does?

Also, I missed the complementary error message "could not unset upstream of HEAD when it does not point to any branch." We should either change the "when" to a "because" in the second message too or rewrite both of these messages entirely.

-Alex
Junio C Hamano· May 5, 2015, 21:58 UTC · re: Alex Henrie · lore

Re: [PATCH] branch: fix funny-sounding error message

Alex Henrie <alexhenrie24@gmail.com> writes:
Show 49 quoted lines
> 2015-05-03 17:54 GMT-06:00 Junio C Hamano <gitster@pobox.com>:
>> Alex Henrie <alexhenrie24@gmail.com> writes:
>>
>>> Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
>>> ---
>>>  builtin/branch.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/builtin/branch.c b/builtin/branch.c
>>> index 1d15037..c0b4bae 100644
>>> --- a/builtin/branch.c
>>> +++ b/builtin/branch.c
>>> @@ -972,7 +972,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
>>>
>>>               if (!branch) {
>>>                       if (!argc || !strcmp(argv[0], "HEAD"))
>>> -                             die(_("could not set upstream of HEAD to %s when "
>>> +                             die(_("could not set upstream of HEAD to %s because "
>>>                                     "it does not point to any branch."),
>>>                                   new_upstream);
>>>                       die(_("no such branch '%s'"), argv[0]);
>>
>> Thanks.
>>
>> To me neither sounds so funny, but both sound somewhat awkward,
>> primarily because it is unclear in the first reading what "it" in
>> "it does not point at any branch" refers to.
>>
>> Perhaps if you explain in the log message to illustrate why you
>> found it funny (and the update text is not), it might help, e.g.
>>
>>     "git branch", ran with <this and that options>, when the current
>>     branch is <in what state>, dies with
>>
>>         fatal: could not set upstream of HEAD to frotz when it does not
>>         point to any branch.
>>
>>     which is funny <because of such and such reasons>.  Saying "because"
>>     makes it <better beause of such and such reasons>.
>>
>> I suspect that this message is about a nonsense attempt to set an
>> upstream for a detached HEAD perhaps?  Then
>>
>>     fatal: cannot set upstream for a detached HEAD
>>
>> may be shorter and more directly points at the root cause of the
>> error?
>
> I don't really understand what this code is doing.

To be honest, I didn't know what was going on at the first glance, either. AND I felt that it is unfair to say "when" was funny, without understanding what it is trying to say---perhaps it may be implying that upstream of HEAD could be set to "%s" when "it" does point at some branch, or something, even though, as I said, "it" is unclear without really knowing the context.

I think this "branch is NULL" condition is when an earlier call to branch_get() returned a NULL, and _one_ way to make that happen is to detach the HEAD. There may be others, but I didn't check.

Show 5 quoted lines
> This error message can be triggered by running `git branch
> --set-upstream-to=origin/master` from a detached head. But if running
> from a detached head is the only way to trigger the error message, why
> does the code use strcmp instead of if (detached) { ... } as other
> code in that function does?

The 'detached' merely is "Is the _current_ HEAD detached?", not "Is the branch the user asked us to do something about the detached HEAD?", I think.

If you are getting a NULL out of branch_get() but the user did "branch -u foo thisbranch", then that is an indication that we shouldn't be saying that "nono, detached HEAD will never have its own upstream", because that is not what the user asked us to do. So "no argument (implying, we defaulted to HEAD) or the argument is spelled HEAD" I think is the right thing to check.

And the other error message "no such branch" hints (again, I didn't follow the codepath) that we may get a NULL in branch if you did "git branch -u foo no-such-branch".

Jeff King· May 5, 2015, 23:06 UTC · re: Junio C Hamano · lore

Re: [PATCH] branch: fix funny-sounding error message

On Tue, May 05, 2015 at 02:58:24PM -0700, Junio C Hamano wrote:
> I think this "branch is NULL" condition is when an earlier call to
> branch_get() returned a NULL, and _one_ way to make that happen is
> to detach the HEAD.  There may be others, but I didn't check.

FWIW, since I have just been looking through the branch code, branch_get() should only return NULL when:

  1. We passed NULL or "HEAD" to it (i.e., we asked for the current branch). If
     you ask for a branch by name, you will always get a non-NULL return,
     even if that branch does not exist.
  2. There is no current branch (i.e., a detached HEAD).
I think the "no such branch" error message here:
               if (!branch) {
                        if (!argc || !strcmp(argv[0], "HEAD"))
                                die(_("could not unset upstream of HEAD when "
                                      "it does not point to any branch."));
			die(_("no such branch '%s'"), argv[0]);
	       }

cannot actually be triggered (and I double-checked that the test suite does not trigger it by replacing it with "exit(141)", which should cause even test_must_fail to complain).

-Peff

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