Re: [PATCH v2] launch_editor(): indicate that Git waits for user input
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Nov 18, 2017, 01:40 UTC
- Message-ID
- <xmqqh8tsqs83.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <CAPig+cQ3a0guJUhnbktrjs6fL6mSrUXmPqR0BafEAOhVr7Sy-w@mail.gmail.com>
Eric Sunshine <sunshine@sunshineco.com> writes:
Show 11 quoted lines
>> @@ -40,6 +40,32 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
>> + static const char *close_notice = NULL;
>> +
>> + if (isatty(2) && !close_notice) {
>
> If you reverse this condition to say (!close_notice && isatty(2)),
> then you save an isatty() invocation each time if close_notice is
> already assigned.
>
> However, it's not clear how much benefit you gain from stashing this
> away in a static variable. Premature optimization?The variable being "static" could be (but it was done primarily because it allowed me not to worry about freeing), but during a single invocation, it primarily is used as a flag "are we showing the editor invocation notice?" two places in the function can use without having to do the same checks twice.
If we want this as an optimization "we've already checked the condition in our previous call, so let's use the result without checking again", then this has to become tristate:
- We haven't checked, and needs checking (probably NULL);
- We have checked, and we know we want to show the notice---here is a string to use when we clear the notice (what we have here);
- We have checked, and we know we do not want to show the notice (there is no provision for this in the posted code---that makes this not an optimization yet).
Perhaps an empty string can be used for the last one, but if/when it is done, the above needs to go in a comment near the definition of the variable.
Show 6 quoted lines
> Should printing of close_notice be done before the error()? Otherwise, > you get this: > > --- 8< --- > Launched your editor (...) ...There was a problem... > --- 8< ---
In my version with a far shorter message, I deliberately chose not to clear the notice. We ran the editor, and we saw a problem. That is what happened and that is what will be left on the terminal.
I agree that the verbose message Lars substituted makes it harder to read.