[RFC] Indicate that Git waits for user input via editor

[RFC] Indicate that Git waits for user input via editor

[Lars Schneider]

Hi,

Git gathers user input via text editor in certain commands (e.g. "git commit").
If you configure a text based editor, such as vi, then this works great as the 
editor is opened in your terminal window in the foreground and in focus.

However, if you configure an editor that runs outside your terminal window then
you might run into the following problem: 
Git opens the editor but the editor is the background or on another screen and 
consequently you don't see the editor. You only see the Git command line 
interface which appears to hang.

I wonder if would make sense to print "Opening editor for user input..." or
something to the screen to make the user aware of the action. Does this sound
sensible to you? Am I missing an existing solution to this problem?

Thanks,
Lars

Re: [RFC] Indicate that Git waits for user input via editor

[Stefan Beller]

On Wed, Nov 15, 2017 at 7:08 AM, Lars Schneider
<larsxschneider@gmail.com> wrote:
> Hi,
>
> Git gathers user input via text editor in certain commands (e.g. "git commit").
> If you configure a text based editor, such as vi, then this works great as the
> editor is opened in your terminal window in the foreground and in focus.
>
> However, if you configure an editor that runs outside your terminal window then
> you might run into the following problem:
> Git opens the editor but the editor is the background or on another screen and
> consequently you don't see the editor. You only see the Git command line
> interface which appears to hang.
>
> I wonder if would make sense to print "Opening editor for user input..." or
> something to the screen to make the user aware of the action. Does this sound
> sensible to you? Am I missing an existing solution to this problem?

Can this be put in a wrapper that opens the text editor?
The wrapper would print these lines and then open the text editor;
depending on the operating system, there might even be a command to
focus on that editor window.

Regarding Git, maybe improve the documentation for how to set the editor
variable?



>
> Thanks,
> Lars

Re: [RFC] Indicate that Git waits for user input via editor

[Lars Schneider]

> On 15 Nov 2017, at 18:51, Stefan Beller <sbeller@google.com> wrote:
> 
> On Wed, Nov 15, 2017 at 7:08 AM, Lars Schneider
> <larsxschneider@gmail.com> wrote:
>> Hi,
>> 
>> Git gathers user input via text editor in certain commands (e.g. "git commit").
>> If you configure a text based editor, such as vi, then this works great as the
>> editor is opened in your terminal window in the foreground and in focus.
>> 
>> However, if you configure an editor that runs outside your terminal window then
>> you might run into the following problem:
>> Git opens the editor but the editor is the background or on another screen and
>> consequently you don't see the editor. You only see the Git command line
>> interface which appears to hang.
>> 
>> I wonder if would make sense to print "Opening editor for user input..." or
>> something to the screen to make the user aware of the action. Does this sound
>> sensible to you? Am I missing an existing solution to this problem?
> 
> Can this be put in a wrapper that opens the text editor?
> The wrapper would print these lines and then open the text editor;
> depending on the operating system, there might even be a command to
> focus on that editor window.

Yeah, that would be a workaround. However, in order to take these steps (write the 
wrapper, enable the focus command) the users needs to understand the problem.
That's quite a leap especially for new Git users. They just get the feeling "Git 
is broken because it hangs".

Can you imagine any downside for an "Opening editor for user input..." message?


> Regarding Git, maybe improve the documentation for how to set the editor
> variable?

The sad truth is that 98% of the users do not read the documentation
(made up number but close to my observed reality).


- Lars

Re: [RFC] Indicate that Git waits for user input via editor

[Stefan Beller]

On Wed, Nov 15, 2017 at 10:07 AM, Lars Schneider
<larsxschneider@gmail.com> wrote:

>> Can this be put in a wrapper that opens the text editor?
>> The wrapper would print these lines and then open the text editor;
>> depending on the operating system, there might even be a command to
>> focus on that editor window.
>
> Yeah, that would be a workaround. However, in order to take these steps (write the
> wrapper, enable the focus command) the users needs to understand the problem.
> That's quite a leap especially for new Git users. They just get the feeling "Git
> is broken because it hangs".
>
> Can you imagine any downside for an "Opening editor for user input..." message?

"Wasting precious screen real estate for power users" (tm)
So maybe if one can turn it off, this would be ok? Or even for known inline
editors?

>> Regarding Git, maybe improve the documentation for how to set the editor
>> variable?
>
> The sad truth is that 98% of the users do not read the documentation
> (made up number but close to my observed reality).

Yeah that is an excellent point, but you forgot the people who
look at stackoverflow which of course links back to the docs in
the first excellent reply.

In a way this suggestion of bettering the docs was a cheap way out, sorry.

Re: [RFC] Indicate that Git waits for user input via editor

[Junio C Hamano]

Lars Schneider <larsxschneider@gmail.com> writes:

> However, if you configure an editor that runs outside your terminal window then
> you might run into the following problem: 
> Git opens the editor but the editor is the background or on another screen and 
> consequently you don't see the editor. You only see the Git command line 
> interface which appears to hang.
>
> I wonder if would make sense to print "Opening editor for user input..." or
> something to the screen to make the user aware of the action. Does this sound
> sensible to you? Am I missing an existing solution to this problem?

My knee-jerk reaction was: for such a user who has EDITOR set to a
program that pops under, wouldn't any program, not just Git, that
uses the editor to open a file for editing/viewing look broken?
Would we care if we are called "broken" by such a clueless user who
cannot tell a (non-)broken caller of an editor and a broken editor?

But that is true only when the user does realize/expect that the
program s/he is running _will_ open an editor at the point of the
workflow.  If s/he types "git merge" or "git rebase -i @{u}", for
example, it is true that the world would be a better place if s/he
knows that would ask a file to be edited with an editor, but it is
unrealisic to expect that everybody knows how to operate these
commands.  Everybody is a newbie at least once.

I wonder if we can do something like

	git_spawn_editor()
	{
		const char *EL = "\033[K"; /* Erase in Line */

		/* notice the lack of terminating LF */
		fprintf(stderr, "Launching your editor...");
		fflush(stderr);

		if (!run_command(... spawn the editor ...)) {
			/* Success! - go back and erase the whole line */
			fprintf(stderr, "\r%s", EL);
		} else {
			fprintf(stderr, "failed (%s)\n", strerror(errno));
		}
		fflush(stderr);
	}

to tentatively give a message without permanently wasting the
vertical space.

Re: [RFC] Indicate that Git waits for user input via editor

[Stefan Beller]

On Wed, Nov 15, 2017 at 2:32 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Lars Schneider <larsxschneider@gmail.com> writes:
>
>> However, if you configure an editor that runs outside your terminal window then
>> you might run into the following problem:
>> Git opens the editor but the editor is the background or on another screen and
>> consequently you don't see the editor. You only see the Git command line
>> interface which appears to hang.
>>
>> I wonder if would make sense to print "Opening editor for user input..." or
>> something to the screen to make the user aware of the action. Does this sound
>> sensible to you? Am I missing an existing solution to this problem?
>
> My knee-jerk reaction was: for such a user who has EDITOR set to a
> program that pops under, wouldn't any program, not just Git, that
> uses the editor to open a file for editing/viewing look broken?
> Would we care if we are called "broken" by such a clueless user who
> cannot tell a (non-)broken caller of an editor and a broken editor?
>
> But that is true only when the user does realize/expect that the
> program s/he is running _will_ open an editor at the point of the
> workflow.  If s/he types "git merge" or "git rebase -i @{u}", for
> example, it is true that the world would be a better place if s/he
> knows that would ask a file to be edited with an editor, but it is
> unrealisic to expect that everybody knows how to operate these
> commands.  Everybody is a newbie at least once.
>
> I wonder if we can do something like
>
>         git_spawn_editor()
>         {
>                 const char *EL = "\033[K"; /* Erase in Line */
>
>                 /* notice the lack of terminating LF */
>                 fprintf(stderr, "Launching your editor...");

"It takes quite some time to launch this special Git Editor"

As Lars pointed out, the editor may be launched in the background,
that the user would not know, but they might expect a thing to
pop up as a modal dialog as is always with UIs.

So despite it being technically wrong at this point in time,
I would phrase it in past tense or in a way that indicates that the
user needs to take action already.

The "Launching..." sounds as if I need to wait for an event to occur.

>                 fflush(stderr);
>
>                 if (!run_command(... spawn the editor ...)) {
>                         /* Success! - go back and erase the whole line */
>                         fprintf(stderr, "\r%s", EL);
>                 } else {
>                         fprintf(stderr, "failed (%s)\n", strerror(errno));
>                 }
>                 fflush(stderr);
>         }
>
> to tentatively give a message without permanently wasting the
> vertical space.

Re: [RFC] Indicate that Git waits for user input via editor

[Junio C Hamano]

Stefan Beller <sbeller@google.com> writes:

>> I wonder if we can do something like
>>
>>         git_spawn_editor()
>>         {
>>                 const char *EL = "\033[K"; /* Erase in Line */
>>
>>                 /* notice the lack of terminating LF */
>>                 fprintf(stderr, "Launching your editor...");
>
> "It takes quite some time to launch this special Git Editor"
>
> As Lars pointed out, the editor may be launched in the background,
> that the user would not know, but they might expect a thing to
> pop up as a modal dialog as is always with UIs.
>
> So despite it being technically wrong at this point in time,
> I would phrase it in past tense or in a way that indicates that the
> user needs to take action already.
>
> The "Launching..." sounds as if I need to wait for an event to occur.

Heh, I wasn't expecting phrasing nitpicks when I was trying to help
the thread by trying to come up with a way to avoid vertical space
wastage.

Re: [RFC] Indicate that Git waits for user input via editor

[Stefan Beller]

On Wed, Nov 15, 2017 at 4:33 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Stefan Beller <sbeller@google.com> writes:
>
>>> I wonder if we can do something like
>>>
>>>         git_spawn_editor()
>>>         {
>>>                 const char *EL = "\033[K"; /* Erase in Line */
>>>
>>>                 /* notice the lack of terminating LF */
>>>                 fprintf(stderr, "Launching your editor...");
>>
>> "It takes quite some time to launch this special Git Editor"
>>
>> As Lars pointed out, the editor may be launched in the background,
>> that the user would not know, but they might expect a thing to
>> pop up as a modal dialog as is always with UIs.
>>
>> So despite it being technically wrong at this point in time,
>> I would phrase it in past tense or in a way that indicates that the
>> user needs to take action already.
>>
>> The "Launching..." sounds as if I need to wait for an event to occur.
>
> Heh, I wasn't expecting phrasing nitpicks when I was trying to help
> the thread by trying to come up with a way to avoid vertical space
> wastage.

I know you weren't, but maybe it is helpful for the author of the patch
(I presume you may not be the author, after all).

But you are right, I should have started with a more fundamental
answer stating this is a good idea, and I cannot think of a negative
side effect currently.

Re: [RFC] Indicate that Git waits for user input via editor

[Junio C Hamano]

Junio C Hamano <gitster@pobox.com> writes:

> I wonder if we can do something like
> ...
> to tentatively give a message without permanently wasting the
> vertical space.

Learning from 13e4760a ("recv_sideband: Do not use ANSI escape
sequence on dumb terminals.", 2008-01-08), I think the above should
be more like this:

	git_spawn_editor()
	{
		static const char *finish;

		if (!finish) {
			const char ANSI_FINISH[] = "\r\033[K";
			const char DUMB_FINISH[] = "done.\n";
			char *term = getenv("TERM");

			if (term && strcmp(term, "dumb"))
				finish = ANSI_FINISH;
			else
				finish = DUMB_FINISH;
		}

		/* notice the lack of terminating LF */
		fprintf(stderr, "Launched your editor, waiting...");
		fflush(stderr);

		if (!run_command(... spawn the editor ...))
			fputs(finish, stderr);
		else
			fprintf(stderr, "failed (%s)\n", strerror(errno));
		fflush(stderr);
	}

[PATCH] launch_editor(): indicate that Git waits for user input

[Junio C Hamano]

When a graphical GIT_EDITOR is spawned by a Git command that opens
and waits for it for the user input (e.g. "git rebase -i") pops its
window elsewhere that is obscure, the user may be left staring the
original terminal window s/he invoked the Git command from, without
even realizing that now s/he needs to interact with another window
the editor is waiting in, before Git can proceed.

Show a message to the original terminal, and get rid of it when the
editor returns.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * I tried this with "emacsclient" but it turns out that Emacs folks
   have already thought about this issue, and the program says
   "Waiting for Emacs..." while it does its thing, so from that
   point of view, perhaps as Stefan said originally, the editor Lars
   had trouble with is what is at fault and needs fixing?  I dunno.

   Also, emacsclient seems to conclude its message, once the editing
   is done, by emitting LF _before_ we have a chance to do the "go
   back to the beginning and clear" dance, so it probably is not a
   very good example to emulate the situation Lars had trouble with.
   You cannot observe the nuking of the "launched, waiting..." with
   it.

 editor.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/editor.c b/editor.c
index 7519edecdc..1321944716 100644
--- a/editor.c
+++ b/editor.c
@@ -40,6 +40,28 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
 		const char *args[] = { editor, real_path(path), NULL };
 		struct child_process p = CHILD_PROCESS_INIT;
 		int ret, sig;
+		static const char *close_notice = NULL;
+
+		if (isatty(2) && !close_notice) {
+			char *term = getenv("TERM");
+
+			if (term && strcmp(term, "dumb"))
+				/*
+				 * go back to the beginning and erase the
+				 * entire line if the terminal is capable
+				 * to do so, to avoid wasting the vertical
+				 * space.
+				 */
+				close_notice = "\r\033[K";
+			else
+				/* otherwise, complete and waste the line */
+				close_notice = "done.\n";
+		}
+
+		if (close_notice) {
+			fprintf(stderr, "Launched your editor, waiting...");
+			fflush(stderr);
+		}
 
 		p.argv = args;
 		p.env = env;
@@ -53,11 +75,14 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
 		sig = ret - 128;
 		sigchain_pop(SIGINT);
 		sigchain_pop(SIGQUIT);
+
 		if (sig == SIGINT || sig == SIGQUIT)
 			raise(sig);
 		if (ret)
 			return error("There was a problem with the editor '%s'.",
 					editor);
+		if (close_notice)
+			fputs(close_notice, stderr);
 	}
 
 	if (!buffer)
-- 
2.15.0-360-gf2497ca0e5

Re: [PATCH] launch_editor(): indicate that Git waits for user input

[Lars Schneider]

> On 16 Nov 2017, at 07:04, Junio C Hamano <gitster@pobox.com> wrote:

Wow. Thanks for the quick patch :-)


> When a graphical GIT_EDITOR is spawned by a Git command that opens
> and waits for it for the user input (e.g. "git rebase -i") pops its
> window elsewhere that is obscure, the user may be left staring the
> original terminal window s/he invoked the Git command from, without
> even realizing that now s/he needs to interact with another window
> the editor is waiting in, before Git can proceed.

Maybe:

When a graphical GIT_EDITOR is spawned by a Git command that opens
and waits for user input (e.g. "git rebase -i"), then the editor window
might be obscured by other windows. The user may be left staring at the 
original Git terminal window without even realizing that s/he needs to 
interact with another window before Git can proceed. To this user Git 
appears hanging.


> Show a message to the original terminal, and get rid of it when the
s/to/in/ ?

> editor returns.



> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
> 
> * I tried this with "emacsclient" but it turns out that Emacs folks
>   have already thought about this issue, and the program says
>   "Waiting for Emacs..." while it does its thing, so from that
>   point of view, perhaps as Stefan said originally, the editor Lars
>   had trouble with is what is at fault and needs fixing?  I dunno.

Based on my (not too extensive) testing, Emacs is probably the only 
editor with this clever behavior.


>   Also, emacsclient seems to conclude its message, once the editing
>   is done, by emitting LF _before_ we have a chance to do the "go
>   back to the beginning and clear" dance, so it probably is not a
>   very good example to emulate the situation Lars had trouble with.
>   You cannot observe the nuking of the "launched, waiting..." with
>   it.
> 
> editor.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
> 
> diff --git a/editor.c b/editor.c
> index 7519edecdc..1321944716 100644
> --- a/editor.c
> +++ b/editor.c
> @@ -40,6 +40,28 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
> 		const char *args[] = { editor, real_path(path), NULL };
> 		struct child_process p = CHILD_PROCESS_INIT;
> 		int ret, sig;
> +		static const char *close_notice = NULL;
> +
> +		if (isatty(2) && !close_notice) {
> +			char *term = getenv("TERM");
> +
> +			if (term && strcmp(term, "dumb"))
> +				/*
> +				 * go back to the beginning and erase the
> +				 * entire line if the terminal is capable
> +				 * to do so, to avoid wasting the vertical
> +				 * space.
> +				 */
> +				close_notice = "\r\033[K";
> +			else
> +				/* otherwise, complete and waste the line */
> +				close_notice = "done.\n";
> +		}
> +
> +		if (close_notice) {
> +			fprintf(stderr, "Launched your editor, waiting...");

I also noticed that some people don't get that they need to save and close the
file to continue. Plus, we should tell them that Git is waiting for *them* and
not anything else. Maybe we should also tell them the editor name, but that might
be too verbose. I dunno. How about this?

	fprintf(stderr, "Launched your editor ('%s'). Adjust, save, and close the file to continue. Waiting for you input... ", editor);
		

- Lars

Re: [PATCH] launch_editor(): indicate that Git waits for user input

[Junio C Hamano]

Lars Schneider <larsxschneider@gmail.com> writes:

>> On 16 Nov 2017, at 07:04, Junio C Hamano <gitster@pobox.com> wrote:
>
> Wow. Thanks for the quick patch :-)

Heh, this is not exactly my itch, so if you are inclined to, can you
take it over from here on?

Thanks.

Re: [PATCH] launch_editor(): indicate that Git waits for user input

[Lars Schneider]

> On 16 Nov 2017, at 15:58, Junio C Hamano <gitster@pobox.com> wrote:
> 
> Lars Schneider <larsxschneider@gmail.com> writes:
> 
>>> On 16 Nov 2017, at 07:04, Junio C Hamano <gitster@pobox.com> wrote:
>> 
>> Wow. Thanks for the quick patch :-)
> 
> Heh, this is not exactly my itch, so if you are inclined to, can you
> take it over from here on?

Absolutely! What is the proper way to proceed here? Should I send a v2
with the changes I suggested? How do I attribute you correctly? I
assume I need to remove your 'Signed-off-by:'?

Thanks,
Lars

Re: [PATCH] launch_editor(): indicate that Git waits for user input

[Junio C Hamano]

Lars Schneider <larsxschneider@gmail.com> writes:

>> On 16 Nov 2017, at 15:58, Junio C Hamano <gitster@pobox.com> wrote:
>> 
>> Lars Schneider <larsxschneider@gmail.com> writes:
>> 
>>>> On 16 Nov 2017, at 07:04, Junio C Hamano <gitster@pobox.com> wrote:
>>> 
>>> Wow. Thanks for the quick patch :-)
>> 
>> Heh, this is not exactly my itch, so if you are inclined to, can you
>> take it over from here on?
>
> Absolutely! What is the proper way to proceed here? Should I send a v2
> with the changes I suggested? How do I attribute you correctly? I
> assume I need to remove your 'Signed-off-by:'?

If you are making major changes over the original patch, you'd
probably want to take the authorship and mention me on Helped-by:
and/or add "This is based on a previous work by...", if you want to
credit me.

If you are not taking the authorship over, then doing something like

    https://public-inbox.org/git/xmqqshdex0ff.fsf@gitster.mtv.corp.google.com/

would be sufficient, I would think.

Thanks.

Re: [PATCH] launch_editor(): indicate that Git waits for user input

[Kaartic Sivaraam]

On Thursday 16 November 2017 11:34 AM, Junio C Hamano wrote:
> 
>   * I tried this with "emacsclient" but it turns out that Emacs folks
>     have already thought about this issue, and the program says
>     "Waiting for Emacs..." while it does its thing, so from that
>     point of view, perhaps as Stefan said originally, the editor Lars
>     had trouble with is what is at fault and needs fixing?  I dunno.
> 
>     Also, emacsclient seems to conclude its message, once the editing
>     is done, by emitting LF _before_ we have a chance to do the "go
>     back to the beginning and clear" dance, so it probably is not a
>     very good example to emulate the situation Lars had trouble with.
>     You cannot observe the nuking of the "launched, waiting..." with
>     it.
>

I tried this patch with 'gedit' and it seems to work fine except for one 
particular case. When the launched editor gets killed somehow when 
waiting for user input, the error message shown in the terminal seems to 
be following the "Launched editor..." message immediately, making it 
hard to identify it.

$ GIT_EDITOR=gedit ./git commit --allow-empty
Launched your editor, waiting...error: gedit died of signal 15
error: There was a problem with the editor 'gedit'.
Please supply the message using either -m or -F option.

Though this is not something that's going to happen very often, I'm not 
sure if this is to be considered. Just wanted to note what I observed.


>   editor.c | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/editor.c b/editor.c
> index 7519edecdc..1321944716 100644
> --- a/editor.c
> +++ b/editor.c
> @@ -40,6 +40,28 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
>   		const char *args[] = { editor, real_path(path), NULL };
>   		struct child_process p = CHILD_PROCESS_INIT;
>   		int ret, sig;
> +		static const char *close_notice = NULL;

Just a little curious, what's the advantage of making 'close_notice' 
'static' over 'auto' ?


> +
> +		if (isatty(2) && !close_notice) {
> +			char *term = getenv("TERM");
> +
> +			if (term && strcmp(term, "dumb"))
> +				/*
> +				 * go back to the beginning and erase the
> +				 * entire line if the terminal is capable
> +				 * to do so, to avoid wasting the vertical
> +				 * space.
> +				 */
> +				close_notice = "\r\033[K";
> +			else
> +				/* otherwise, complete and waste the line */
> +				close_notice = "done.\n";
> +		}
> +
> +		if (close_notice) {
> +			fprintf(stderr, "Launched your editor, waiting...");
> +			fflush(stderr);

Being curious again, is flushing 'stderr' required ? AFAIK, 'stderr' is 
unbuffered by default and I didn't notice any calls that changed the 
buffering mode of it along this code path.


> +		}
>   
>   		p.argv = args;
>   		p.env = env;
> @@ -53,11 +75,14 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
>   		sig = ret - 128;
>   		sigchain_pop(SIGINT);
>   		sigchain_pop(SIGQUIT);
> +
>   		if (sig == SIGINT || sig == SIGQUIT)
>   			raise(sig);
>   		if (ret)
>   			return error("There was a problem with the editor '%s'.",
>   					editor);
> +		if (close_notice)
> +			fputs(close_notice, stderr);
>   	}
>   
>   	if (!buffer)
> 

Re: [PATCH] launch_editor(): indicate that Git waits for user input

[Junio C Hamano]

Kaartic Sivaraam <kaartic.sivaraam@gmail.com> writes:

> $ GIT_EDITOR=gedit ./git commit --allow-empty
> Launched your editor, waiting...error: gedit died of signal 15
> error: There was a problem with the editor 'gedit'.
> Please supply the message using either -m or -F option.
>
> Though this is not something that's going to happen very often, I'm
> not sure if this is to be considered. Just wanted to note what I
> observed.

See my earlier response to Eric Sunshine.

>> +		static const char *close_notice = NULL;
>
> Just a little curious, what's the advantage of making 'close_notice'
> 'static' over 'auto' ?

A second call, if an earlier call to the function already determined
that our standard error output is going to a terminal and what kind
of terminal we are on, would just use the result from the earliser
call.

> Being curious again, is flushing 'stderr' required ? AFAIK, 'stderr'
> is unbuffered by default and I didn't notice any calls that changed
> the buffering mode of it along this code path.

"By default" is the key phrase.  The code is merely being defensive
to changes in other area of the code.