[RFD] Place to document magic pathspecs like ":/" and pathspec handling

[RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Jakub Narębski]

Hello,

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I have noticed that the magic pathspec ":/" is described only in RelNotes
for revision 1.7.6:

|* A magic pathspec ":/" tells a command that limits its operation to the current directory when ran from a subdirectory to work on the entire working tree. In general, ":/path/to/file" would be relative to the root of the working tree hierarchy. After "git reset --hard; edit Makefile; cd t/", "git add -u" would be a no-op, but "git add -u :/" would add the updated contents of the Makefile at the top level. If you want to name a path in the current subdirectory whose unusual name begins with ":/", you can name it by "./:/that/path" or by "\:/that/path".|

||
|I think the reason might be that there was no good place to put that
information in.  Nowadays we have gitcli(7) manual page, but perhaps
it would be better to create a separate manpage for issues related
to pathspec handling (of which ":/" is only one part)... but then
what should it be named?

What do you think?
-- 
Jakub Narębski
|||

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Junio C Hamano]

On Wed, Jun 29, 2016 at 12:47 PM, Jakub Narębski <jnareb@gmail.com> wrote:
>
> I have noticed that the magic pathspec ":/" is described only in RelNotes
> for revision 1.7.6:
> |I think the reason might be that there was no good place to put that
> information in.  Nowadays we have gitcli(7) manual page, but perhaps

$ git help glossary

look for pathspec.

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Jakub Narębski]

W dniu 2016-06-29 o 21:51, Junio C Hamano pisze:
> On Wed, Jun 29, 2016 at 12:47 PM, Jakub Narębski <jnareb@gmail.com> wrote:
>> I have noticed that the magic pathspec ":/" is described only in RelNotes
>> for revision 1.7.6:
>> |I think the reason might be that there was no good place to put that
>> information in.  Nowadays we have gitcli(7) manual page, but perhaps
> $ git help glossary
>
> look for pathspec.
Thanks. I haven't noticed that.

But I think it is not the best place to keep this documentation.
There are the following issues with it:

* it is hard to find; I did not search _glossary_ for information
  about how Git handles pathspecs, I would search it if I didn't know
  what pathspec means.

* it is longest entry in glossary, and the only one with nested
  list, but

* it is also too short to describe how Git handles pathspecs in detail,
  and a bit cryptic; there are no examples (so grepping docs for '":/"'
  didn't found it).

-- 
Jakub Narębski

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Junio C Hamano]

Jakub Narębski <jnareb@gmail.com> writes:

> But I think it is not the best place to keep this documentation.

All true.  In case it was not obvious, I didn't mean to say "Here
you find the information, shut up."  It was "here is a pointer if
you didn't find it, so that you can use it as a starting point to
make a better documentation."

An analogous entity in the world model of Git that appears
everywhere and is not limited to a single command is the revision
set calculus.  Where do we describe it and how do we make it
discoverable?  Can the new way to describe pathspec and pathspec
magic mimic the way it is done for the revisions?

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Jakub Narębski]

W dniu 2016-06-29 o 23:28, Junio C Hamano pisze:
> Jakub Narębski <jnareb@gmail.com> writes:
> 
>> But I think it is not the best place to keep this documentation.
> 
> All true.  In case it was not obvious, I didn't mean to say "Here
> you find the information, shut up."  It was "here is a pointer if
> you didn't find it, so that you can use it as a starting point to
> make a better documentation."
> 
> An analogous entity in the world model of Git that appears
> everywhere and is not limited to a single command is the revision
> set calculus.  Where do we describe it and how do we make it
> discoverable?  Can the new way to describe pathspec and pathspec
> magic mimic the way it is done for the revisions?

Is that a trick question? :-P

The revision set calculus is described as a standalone documentation
in the gitrevisions(7) manpage (titled "specifying revisions and
[revision] ranges for Git"... well, the "[revision]" isn't there).
This documentation is also accessible via `git help revisions`,
which is cool.  It is referenced in the "Symbolic Identifiers"
section of the git(1) manual page.

Long time ago the description of revision set calculus was hidden
in the manpage for the plumbing command git-rev-parse, and is still
included in it (the common part is, via "include::revisions.txt[]").

As I wrote:

>>>> Nowadays we have gitcli(7) manual page, but perhaps
>>>> it would be better to create a separate manpage for issues related
>>>> to pathspec handling (of which ":/" is only one part)... but then
>>>> what should it be named?

So we could describe how Git handles pathspecs and pathspec magic
in the new manual page named gitpathspec(7), or gitpaths(7). The
former has the advantage of the name being identical to the entry
in gitglossary(7). The latter has the probable advantage of being
easier for the Git novice to find, and that it could be used to
gather various ways to generate list of files in Git (files in
the working area, files in the staging area aka the index, files
in the revision / tree object, changed files, etc.); the pathspec
in strict sense is about the input. Well, we could have 'manpage
alias' of gitpaths to gitpathspec, or vice versa.

 Sidenote: I wonder if people (especially novices) have problem
 finding relevant documentation, and if adding something like 
 "git apropos <topic>" command ("apropos", or "man -k"), or
 add the '--apropos' option to "git help" would be useful...
 and if it would be easy to create.

The description from gitglossary would be a good start, as would
parts of gitcli and relevant RelNotes. It would need to be linked
from git(1) manpage, and probably also from gitcli.

Now only to start it...
-- 
Jakub Narębski

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Duy Nguyen]

Hi Jakub,

Where have you been all these years? :D

On Thu, Jun 30, 2016 at 11:42 AM, Jakub Narębski <jnareb@gmail.com> wrote:
>>>>> Nowadays we have gitcli(7) manual page, but perhaps
>>>>> it would be better to create a separate manpage for issues related
>>>>> to pathspec handling (of which ":/" is only one part)... but then
>>>>> what should it be named?
>
> So we could describe how Git handles pathspecs and pathspec magic
> in the new manual page named gitpathspec(7), or gitpaths(7). The
> former has the advantage of the name being identical to the entry
> in gitglossary(7). The latter has the probable advantage of being
> easier for the Git novice to find,

git-pathspec(7) is a great idea. It bugs me that all the pathspec
details are hidden in that glossary file (though I didn't know it was
also available via "git help glossary", which probably just reinforces
its invisibility). The closet place I could think of was git(1) but
that page is already very long.

> and that it could be used to
> gather various ways to generate list of files in Git (files in
> the working area, files in the staging area aka the index, files
> in the revision / tree object, changed files, etc.);

You mean the list of commands in this man page? OK. Another thing we
could do is the reverse direction, add gitpathspec(7) as a reference
to all commands that may need it.

> the pathspec
> in strict sense is about the input. Well, we could have 'manpage
> alias' of gitpaths to gitpathspec, or vice versa.

>  Sidenote: I wonder if people (especially novices) have problem
>  finding relevant documentation, and if adding something like
>  "git apropos <topic>" command ("apropos", or "man -k"), or
>  add the '--apropos' option to "git help" would be useful...
>  and if it would be easy to create.

I have that problem sometimes and I don't think I can call myself a
noob anymore. I usually need to do some grepping. So yeah "git
apropos" would be great.
-- 
Duy

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Jeff King]

On Thu, Jun 30, 2016 at 05:14:15PM +0200, Duy Nguyen wrote:

> > So we could describe how Git handles pathspecs and pathspec magic
> > in the new manual page named gitpathspec(7), or gitpaths(7). The
> > former has the advantage of the name being identical to the entry
> > in gitglossary(7). The latter has the probable advantage of being
> > easier for the Git novice to find,
> 
> git-pathspec(7) is a great idea. It bugs me that all the pathspec
> details are hidden in that glossary file (though I didn't know it was
> also available via "git help glossary", which probably just reinforces
> its invisibility). The closet place I could think of was git(1) but
> that page is already very long.
> 
> > and that it could be used to
> > gather various ways to generate list of files in Git (files in
> > the working area, files in the staging area aka the index, files
> > in the revision / tree object, changed files, etc.);
> 
> You mean the list of commands in this man page? OK. Another thing we
> could do is the reverse direction, add gitpathspec(7) as a reference
> to all commands that may need it.

I'll second (third?) this. Some of our manpages are quite unwieldy, and
I don't think we are doing any favors to users when we auto-include the
same content in multiple places. I think we should instead be splitting
concepts into their own pages and referring to them. That helps users
build the mental model ("aha, pathspecs; I read that concept page and
know how those work!" instead of "here's 3 pages of description on how
git-diff handles paths. Is it identical to the 3 pages in git-log?").

I suspect some things like diff options could benefit from a similar
split.

> >  Sidenote: I wonder if people (especially novices) have problem
> >  finding relevant documentation, and if adding something like
> >  "git apropos <topic>" command ("apropos", or "man -k"), or
> >  add the '--apropos' option to "git help" would be useful...
> >  and if it would be easy to create.
> 
> I have that problem sometimes and I don't think I can call myself a
> noob anymore. I usually need to do some grepping. So yeah "git
> apropos" would be great.

I think better searching would help a lot if we split things into more
pages (right now, a legitimate technique is "man git-foo", using search
in the pager, and wading through all of the false positives. That sucks,
but at least you can find what you want _eventually_).

I'm not sure if "man -k" is all that great, though, for two reasons:

  1. AFAIK there isn't an easy way to restrict it only to git manpages
     (try "man -k git"; oh, hello "isxdigit(3posix)").

  2. It only searches the title lines. So it's great for finding the
     pathspec page, but you could probably already do that by guessing
     it's called "git help pathspecs". But if you're looking for
     discussion of a particular diff option, say, it would be nice to be
     able to search for all mentions of "--word-diff-regex", or
     something.

     There is "man -K", but it kind of sucks (it seems to just dump you
     in any manpage that matches, in a list).

I don't think those are problems that _git_ should necessarily be
solving, though. It's a general problem for manpages. And there may be
better "man" implementations than I'm used to (or even options or
configuration I don't know about).

-Peff

Re: [RFD] Place to document magic pathspecs like ":/" and pathspec handling

[Jakub Narębski]

W dniu 2016-07-01 o 08:42, Jeff King pisze:
> On Thu, Jun 30, 2016 at 05:14:15PM +0200, Duy Nguyen wrote:
> 
>>> So we could describe how Git handles pathspecs and pathspec magic
>>> in the new manual page named gitpathspec(7), or gitpaths(7). The
>>> former has the advantage of the name being identical to the entry
>>> in gitglossary(7). The latter has the probable advantage of being
>>> easier for the Git novice to find,
>>
>> git-pathspec(7) is a great idea. It bugs me that all the pathspec
>> details are hidden in that glossary file (though I didn't know it was
>> also available via "git help glossary", which probably just reinforces
>> its invisibility). The closet place I could think of was git(1) but
>> that page is already very long.
>>
>>> and that it could be used to
>>> gather various ways to generate list of files in Git (files in
>>> the working area, files in the staging area aka the index, files
>>> in the revision / tree object, changed files, etc.);
>>
>> You mean the list of commands in this man page? OK. Another thing we
>> could do is the reverse direction, add gitpathspec(7) as a reference
>> to all commands that may need it.
> 
> I'll second (third?) this. Some of our manpages are quite unwieldy, and
> I don't think we are doing any favors to users when we auto-include the
> same content in multiple places. I think we should instead be splitting
> concepts into their own pages and referring to them. That helps users
> build the mental model ("aha, pathspecs; I read that concept page and
> know how those work!" instead of "here's 3 pages of description on how
> git-diff handles paths. Is it identical to the 3 pages in git-log?").
> 
> I suspect some things like diff options could benefit from a similar
> split.

I'd rather we keep manpages self-contained; one reason is as you said
below easier searching.  I also prefer not to have to follow from one
page to another.

On the contrary, I think it would be good idea to include full list
of a configuration variables affecting specific command in its manpage.
Currently almost all configuration variables are in git-config(1)
manpage, but some are in individual manpages, and only linked there.

Redundancy in reference documentation is not bad, provided that it
doesn't require duplication in documentation sources, and that the
documentation itself is not too long, and not too unwieldy.

>>>  Sidenote: I wonder if people (especially novices) have problem
>>>  finding relevant documentation, and if adding something like
>>>  "git apropos <topic>" command ("apropos", or "man -k"), or
>>>  add the '--apropos' option to "git help" would be useful...
>>>  and if it would be easy to create.
>>
>> I have that problem sometimes and I don't think I can call myself a
>> noob anymore. I usually need to do some grepping. So yeah "git
>> apropos" would be great.
> 
> I think better searching would help a lot if we split things into more
> pages (right now, a legitimate technique is "man git-foo", using search
> in the pager, and wading through all of the false positives. That sucks,
> but at least you can find what you want _eventually_).
> 
> I'm not sure if "man -k" is all that great, though, for two reasons:
> 
>   1. AFAIK there isn't an easy way to restrict it only to git manpages
>      (try "man -k git"; oh, hello "isxdigit(3posix)").

One solution would be to use "apropos" / "man -k" and then filter it
(e.g. with /^git/) to filter out non-git manpages. 

Another would be to search whatis database ourselves. Yet another 
to create whatis-like database, and put it in /usr/share/doc/*.
In both of those cases Git would search the 'database' itself.

>   2. It only searches the title lines. So it's great for finding the
>      pathspec page, but you could probably already do that by guessing
>      it's called "git help pathspecs". But if you're looking for
>      discussion of a particular diff option, say, it would be nice to be
>      able to search for all mentions of "--word-diff-regex", or
>      something.

Well, for apropos-like command to work well we would need better
description of manpages, isn't it?. It is getting better, but we still
have a bit to go...

If Git was to create a whatis-like database (for future "--apropos" and
"--whatis" options to "git help"), it could add extra information, for
example keywords (which would have to be added to manpages sources,
and embedded in whatis-like database when creating man, html, etc.
documentaion formats, i.e. when building documentation).
 
>      There is "man -K", but it kind of sucks (it seems to just dump you
>      in any manpage that matches, in a list).

By default Git installs into /usr/share/doc/git-x.y.z the *.txt and *.html
documentation formats. We could follow "man -K" / "man --global-apropos"
example and search sources... but then we would need to follow inclusions
at least for it to be useful. We could search HTML version of manpages...
but then we would have to strip formatting codes before performing a search.
 
> I don't think those are problems that _git_ should necessarily be
> solving, though. It's a general problem for manpages. And there may be
> better "man" implementations than I'm used to (or even options or
> configuration I don't know about).

I wonder what other version control systems do, like Mercurial, or
Subversion, or Veracity with providing access to their reference docs...

-- 
Jakub Narębski