[PATCH 0/2] Improve gitignore documentation wrt excluded directories

[PATCH 0/2] Improve gitignore documentation wrt excluded directories

[Karsten Blees]

Also here:
https://github.com/kblees/git/commits/kb/gitignore-doc

These two patches were the result of a discussion mid-october [1] that I almost forgot about...now including an example as suggested by Jeff.

[1] http://thread.gmane.org/gmane.comp.version-control.git/235753/focus=235856

Karsten Blees (2):
  gitignore.txt: fix documentation of "**" patterns
  gitignore.txt: clarify recursive nature of excluded directories

 Documentation/gitignore.txt | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

-- 
1.8.4.msysgit.0.12.g88f5ed0

[PATCH 1/2] gitignore.txt: fix documentation of "**" patterns

[Karsten Blees]

"**" means bold in ASCIIDOC, so we need to escape it.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 Documentation/gitignore.txt | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
index 54e334e..f971960 100644
--- a/Documentation/gitignore.txt
+++ b/Documentation/gitignore.txt
@@ -113,12 +113,12 @@ full pathname may have special meaning:
 
  - A leading "`**`" followed by a slash means match in all
    directories. For example, "`**/foo`" matches file or directory
-   "`foo`" anywhere, the same as pattern "`foo`". "**/foo/bar"
+   "`foo`" anywhere, the same as pattern "`foo`". "`**/foo/bar`"
    matches file or directory "`bar`" anywhere that is directly
    under directory "`foo`".
 
- - A trailing "/**" matches everything inside. For example,
-   "abc/**" matches all files inside directory "abc", relative
+ - A trailing "`/**`" matches everything inside. For example,
+   "`abc/**`" matches all files inside directory "`abc`", relative
    to the location of the `.gitignore` file, with infinite depth.
 
  - A slash followed by two consecutive asterisks then a slash
-- 
1.8.4.msysgit.0.12.g88f5ed0

Re: [PATCH 1/2] gitignore.txt: fix documentation of "**" patterns

[Junio C Hamano]

Karsten Blees <karsten.blees@gmail.com> writes:

> "**" means bold in ASCIIDOC, so we need to escape it.
>
> Signed-off-by: Karsten Blees <blees@dcon.de>
> ---
>  Documentation/gitignore.txt | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
> index 54e334e..f971960 100644
> --- a/Documentation/gitignore.txt
> +++ b/Documentation/gitignore.txt
> @@ -113,12 +113,12 @@ full pathname may have special meaning:
>  
>   - A leading "`**`" followed by a slash means match in all
>     directories. For example, "`**/foo`" matches file or directory
> -   "`foo`" anywhere, the same as pattern "`foo`". "**/foo/bar"
> +   "`foo`" anywhere, the same as pattern "`foo`". "`**/foo/bar`"
>     matches file or directory "`bar`" anywhere that is directly
>     under directory "`foo`".
>  
> - - A trailing "/**" matches everything inside. For example,
> -   "abc/**" matches all files inside directory "abc", relative
> + - A trailing "`/**`" matches everything inside. For example,
> +   "`abc/**`" matches all files inside directory "`abc`", relative
>     to the location of the `.gitignore` file, with infinite depth.

All, including the quoting of `abc` that does not have anything to
do with the double-asterisk, look good; thanks.

>  
>   - A slash followed by two consecutive asterisks then a slash

[PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Karsten Blees]

Additionally, precedence of negated patterns is exactly as outlined in
the DESCRIPTION section, we don't need to repeat this.

Signed-off-by: Karsten Blees <blees@dcon.de>
---
 Documentation/gitignore.txt | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
index f971960..5ecc48e 100644
--- a/Documentation/gitignore.txt
+++ b/Documentation/gitignore.txt
@@ -79,8 +79,9 @@ PATTERN FORMAT
 
  - An optional prefix "`!`" which negates the pattern; any
    matching file excluded by a previous pattern will become
-   included again.  If a negated pattern matches, this will
-   override lower precedence patterns sources.
+   included again. It is not possible to re-include a file if a parent
+   directory of that file is excluded (i.e. excluding a directory
+   will recursively and irrevocably exclude the entire content).
    Put a backslash ("`\`") in front of the first "`!`" for patterns
    that begin with a literal "`!`", for example, "`\!important!.txt`".
 
@@ -182,6 +183,19 @@ Another example:
 The second .gitignore prevents Git from ignoring
 `arch/foo/kernel/vmlinux.lds.S`.
 
+Example to exclude everything except a specific directory `foo/bar`
+(note the `/*` - without the slash, the wildcard would also exclude
+everything within `foo/bar`):
+
+--------------------------------------------------------------
+    $ cat .gitignore
+    # exclude everything except directory foo/bar
+    /*
+    !/foo
+    /foo/*
+    !/foo/bar
+--------------------------------------------------------------
+
 SEE ALSO
 --------
 linkgit:git-rm[1],
-- 
1.8.4.msysgit.0.12.g88f5ed0

Re: [PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Junio C Hamano]

Karsten Blees <karsten.blees@gmail.com> writes:

> Additionally, precedence of negated patterns is exactly as outlined in
> the DESCRIPTION section, we don't need to repeat this.

Very good, thanks.

Even though I have a suspicion that somebody else may be able to
come up with a better phrase that does not sound unnecessarily
strongly than "recursively and irrevocably", that somebody else is
not me, so I'll queue this as-is for now.

>
> Signed-off-by: Karsten Blees <blees@dcon.de>
> ---
>  Documentation/gitignore.txt | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
> index f971960..5ecc48e 100644
> --- a/Documentation/gitignore.txt
> +++ b/Documentation/gitignore.txt
> @@ -79,8 +79,9 @@ PATTERN FORMAT
>  
>   - An optional prefix "`!`" which negates the pattern; any
>     matching file excluded by a previous pattern will become
> -   included again.  If a negated pattern matches, this will
> -   override lower precedence patterns sources.
> +   included again. It is not possible to re-include a file if a parent
> +   directory of that file is excluded (i.e. excluding a directory
> +   will recursively and irrevocably exclude the entire content).
>     Put a backslash ("`\`") in front of the first "`!`" for patterns
>     that begin with a literal "`!`", for example, "`\!important!.txt`".
>  
> @@ -182,6 +183,19 @@ Another example:
>  The second .gitignore prevents Git from ignoring
>  `arch/foo/kernel/vmlinux.lds.S`.
>  
> +Example to exclude everything except a specific directory `foo/bar`
> +(note the `/*` - without the slash, the wildcard would also exclude
> +everything within `foo/bar`):
> +
> +--------------------------------------------------------------
> +    $ cat .gitignore
> +    # exclude everything except directory foo/bar
> +    /*
> +    !/foo
> +    /foo/*
> +    !/foo/bar
> +--------------------------------------------------------------
> +
>  SEE ALSO
>  --------
>  linkgit:git-rm[1],

Re: [PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Junio C Hamano]

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

> Karsten Blees <karsten.blees@gmail.com> writes:
>
>> Additionally, precedence of negated patterns is exactly as outlined in
>> the DESCRIPTION section, we don't need to repeat this.
>
> Very good, thanks.
>
> Even though I have a suspicion that somebody else may be able to
> come up with a better phrase that does not sound unnecessarily
> strongly than "recursively and irrevocably", that somebody else is
> not me, so I'll queue this as-is for now.

Just in case somebody thinks about rephrasing, to me, these two
words sound heavier than the information they actually convey, and
that is why I said "unnecessarily strong".

The key thing in the behaviour when a directory is excluded is that
it tells us to stop going into that directory, and there is no way
to override it with another .gitignore file somewhere inside,
because we are told not to even bother looking for it.  "Recursively
and irrevocably" may be an accurate description of the end result,
but that sounds more like a rule without a "because"; to a reader
(me), it lacks the "aha, of course" that comes from understanding
why.

>> Signed-off-by: Karsten Blees <blees@dcon.de>
>> ---
>>  Documentation/gitignore.txt | 18 ++++++++++++++++--
>>  1 file changed, 16 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
>> index f971960..5ecc48e 100644
>> --- a/Documentation/gitignore.txt
>> +++ b/Documentation/gitignore.txt
>> @@ -79,8 +79,9 @@ PATTERN FORMAT
>>  
>>   - An optional prefix "`!`" which negates the pattern; any
>>     matching file excluded by a previous pattern will become
>> -   included again.  If a negated pattern matches, this will
>> -   override lower precedence patterns sources.
>> +   included again. It is not possible to re-include a file if a parent
>> +   directory of that file is excluded (i.e. excluding a directory
>> +   will recursively and irrevocably exclude the entire content).
>>     Put a backslash ("`\`") in front of the first "`!`" for patterns
>>     that begin with a literal "`!`", for example, "`\!important!.txt`".
>>  
>> @@ -182,6 +183,19 @@ Another example:
>>  The second .gitignore prevents Git from ignoring
>>  `arch/foo/kernel/vmlinux.lds.S`.
>>  
>> +Example to exclude everything except a specific directory `foo/bar`
>> +(note the `/*` - without the slash, the wildcard would also exclude
>> +everything within `foo/bar`):
>> +
>> +--------------------------------------------------------------
>> +    $ cat .gitignore
>> +    # exclude everything except directory foo/bar
>> +    /*
>> +    !/foo
>> +    /foo/*
>> +    !/foo/bar
>> +--------------------------------------------------------------
>> +
>>  SEE ALSO
>>  --------
>>  linkgit:git-rm[1],

Re: [PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Jeff King]

On Thu, Nov 07, 2013 at 11:37:38AM -0800, Junio C Hamano wrote:

> Junio C Hamano <gitster@pobox.com> writes:
> 
> > Karsten Blees <karsten.blees@gmail.com> writes:
> >
> >> Additionally, precedence of negated patterns is exactly as outlined in
> >> the DESCRIPTION section, we don't need to repeat this.
> >
> > Very good, thanks.
> >
> > Even though I have a suspicion that somebody else may be able to
> > come up with a better phrase that does not sound unnecessarily
> > strongly than "recursively and irrevocably", that somebody else is
> > not me, so I'll queue this as-is for now.
> 
> Just in case somebody thinks about rephrasing, to me, these two
> words sound heavier than the information they actually convey, and
> that is why I said "unnecessarily strong".

I agree that it seems unnecessarily strong.  The word "irrevocable" to
me implies that it cannot ever be changed. But of course it is only
irrevocable for the particular run; you can always edit the .gitignore
file. :)

> The key thing in the behaviour when a directory is excluded is that
> it tells us to stop going into that directory, and there is no way
> to override it with another .gitignore file somewhere inside,
> because we are told not to even bother looking for it.  "Recursively
> and irrevocably" may be an accurate description of the end result,
> but that sounds more like a rule without a "because"; to a reader
> (me), it lacks the "aha, of course" that comes from understanding
> why.

I think it is more than just "we do not descend and so do not read the
.gitignore file". I thought the previous discussion on this topic showed
that you cannot do:

  $ cat .gitignore
  foo
  !foo/bar

to see foo/bar.

> >>   - An optional prefix "`!`" which negates the pattern; any
> >>     matching file excluded by a previous pattern will become
> >> -   included again.  If a negated pattern matches, this will
> >> -   override lower precedence patterns sources.
> >> +   included again. It is not possible to re-include a file if a parent
> >> +   directory of that file is excluded (i.e. excluding a directory
> >> +   will recursively and irrevocably exclude the entire content).
> >>     Put a backslash ("`\`") in front of the first "`!`" for patterns
> >>     that begin with a literal "`!`", for example, "`\!important!.txt`".

How about:

  It is not possible to re-include a file if a parent directory of that
  file is excluded. Once git considers a directory excluded, it does not
  descend into the directory to consider its contents further.

> >> +Example to exclude everything except a specific directory `foo/bar`
> >> +(note the `/*` - without the slash, the wildcard would also exclude
> >> +everything within `foo/bar`):
> >> +
> >> +--------------------------------------------------------------
> >> +    $ cat .gitignore
> >> +    # exclude everything except directory foo/bar
> >> +    /*
> >> +    !/foo
> >> +    /foo/*
> >> +    !/foo/bar
> >> +--------------------------------------------------------------

That looks good to me. The simplest example would be handling a
top-level directory (i.e., ignore all except `/foo`). That is a subset
of what's happening above, and I think showing the general case is good.
I'd worry slightly that a non-astute reader might not figure out how to
simplify down to the top-level case, and we should have two examples. I
may just be overly pessimistic, though.

-Peff

Re: [PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Karsten Blees]

Am 07.11.2013 20:55, schrieb Jeff King:
> On Thu, Nov 07, 2013 at 11:37:38AM -0800, Junio C Hamano wrote:
> 
>> Junio C Hamano <gitster@pobox.com> writes:
>>
>>> Karsten Blees <karsten.blees@gmail.com> writes:
>>>
>>>> Additionally, precedence of negated patterns is exactly as outlined in
>>>> the DESCRIPTION section, we don't need to repeat this.
>>>
>>> Very good, thanks.
>>>
>>> Even though I have a suspicion that somebody else may be able to
>>> come up with a better phrase that does not sound unnecessarily
>>> strongly than "recursively and irrevocably", that somebody else is
>>> not me, so I'll queue this as-is for now.
>>
>> Just in case somebody thinks about rephrasing, to me, these two
>> words sound heavier than the information they actually convey, and
>> that is why I said "unnecessarily strong".
> 
> I agree that it seems unnecessarily strong.  The word "irrevocable" to
> me implies that it cannot ever be changed. But of course it is only
> irrevocable for the particular run; you can always edit the .gitignore
> file. :)
> 
>> The key thing in the behaviour when a directory is excluded is that
>> it tells us to stop going into that directory, and there is no way
>> to override it with another .gitignore file somewhere inside,
>> because we are told not to even bother looking for it.  "Recursively
>> and irrevocably" may be an accurate description of the end result,
>> but that sounds more like a rule without a "because"; to a reader
>> (me), it lacks the "aha, of course" that comes from understanding
>> why.
> 
> I think it is more than just "we do not descend and so do not read the
> .gitignore file". I thought the previous discussion on this topic showed
> that you cannot do:
> 
>   $ cat .gitignore
>   foo
>   !foo/bar
> 
> to see foo/bar.
>

Yes, the pattern could be in .git/info/exclude and it still wouldn't work.
 
>>>>   - An optional prefix "`!`" which negates the pattern; any
>>>>     matching file excluded by a previous pattern will become
>>>> -   included again.  If a negated pattern matches, this will
>>>> -   override lower precedence patterns sources.
>>>> +   included again. It is not possible to re-include a file if a parent
>>>> +   directory of that file is excluded (i.e. excluding a directory
>>>> +   will recursively and irrevocably exclude the entire content).
>>>>     Put a backslash ("`\`") in front of the first "`!`" for patterns
>>>>     that begin with a literal "`!`", for example, "`\!important!.txt`".
> 
> How about:
> 
>   It is not possible to re-include a file if a parent directory of that
>   file is excluded. Once git considers a directory excluded, it does not
>   descend into the directory to consider its contents further.
> 

Hmm...an unsuspecting reader might still assume that it works in top-level .gitignore, given the precendence rules above...

How about this:

   It is not possible to re-include a file if a parent directory of that
   file is excluded. Git doesn't list excluded directories for performance
   reasons, so any patterns on contained files have no effect, no matter
   where they are defined.

>>>> +Example to exclude everything except a specific directory `foo/bar`
>>>> +(note the `/*` - without the slash, the wildcard would also exclude
>>>> +everything within `foo/bar`):
>>>> +
>>>> +--------------------------------------------------------------
>>>> +    $ cat .gitignore
>>>> +    # exclude everything except directory foo/bar
>>>> +    /*
>>>> +    !/foo
>>>> +    /foo/*
>>>> +    !/foo/bar
>>>> +--------------------------------------------------------------
> 
> That looks good to me. The simplest example would be handling a
> top-level directory (i.e., ignore all except `/foo`). That is a subset
> of what's happening above, and I think showing the general case is good.
> I'd worry slightly that a non-astute reader might not figure out how to
> simplify down to the top-level case, and we should have two examples. I
> may just be overly pessimistic, though.
> 
> -Peff
> 

Re: [PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Jeff King]

On Thu, Nov 07, 2013 at 09:27:16PM +0100, Karsten Blees wrote:

> > How about:
> > 
> >   It is not possible to re-include a file if a parent directory of that
> >   file is excluded. Once git considers a directory excluded, it does not
> >   descend into the directory to consider its contents further.
> > 
> 
> Hmm...an unsuspecting reader might still assume that it works in
> top-level .gitignore, given the precendence rules above...
> 
> How about this:
> 
>    It is not possible to re-include a file if a parent directory of that
>    file is excluded. Git doesn't list excluded directories for performance
>    reasons, so any patterns on contained files have no effect, no matter
>    where they are defined.

Yeah, I like that.

-Peff

[PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Karsten Blees]

Additionally, precedence of negated patterns is exactly as outlined in
the DESCRIPTION section, we don't need to repeat this.

Signed-off-by: Karsten Blees <blees@dcon.de>
---

I also force-pushed to git://github.com/kblees/git.git kb/gitignore-doc.

 Documentation/gitignore.txt | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
index f971960..205e80e 100644
--- a/Documentation/gitignore.txt
+++ b/Documentation/gitignore.txt
@@ -79,8 +79,10 @@ PATTERN FORMAT
 
  - An optional prefix "`!`" which negates the pattern; any
    matching file excluded by a previous pattern will become
-   included again.  If a negated pattern matches, this will
-   override lower precedence patterns sources.
+   included again. It is not possible to re-include a file if a parent
+   directory of that file is excluded. Git doesn't list excluded
+   directories for performance reasons, so any patterns on contained
+   files have no effect, no matter where they are defined.
    Put a backslash ("`\`") in front of the first "`!`" for patterns
    that begin with a literal "`!`", for example, "`\!important!.txt`".
 
@@ -182,6 +184,19 @@ Another example:
 The second .gitignore prevents Git from ignoring
 `arch/foo/kernel/vmlinux.lds.S`.
 
+Example to exclude everything except a specific directory `foo/bar`
+(note the `/*` - without the slash, the wildcard would also exclude
+everything within `foo/bar`):
+
+--------------------------------------------------------------
+    $ cat .gitignore
+    # exclude everything except directory foo/bar
+    /*
+    !/foo
+    /foo/*
+    !/foo/bar
+--------------------------------------------------------------
+
 SEE ALSO
 --------
 linkgit:git-rm[1],
-- 
1.8.4.msysgit.1

Re: [PATCH 2/2] gitignore.txt: clarify recursive nature of excluded directories

[Junio C Hamano]

Thanks; will queue.