[PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Laszlo Ersek]

The "--function-context" ("-W") option of git-diff displays the entire
body of a modified function, not just small modified hunks within the
function. It is useful for reviewers when the code changes to the function
are small, but they could affect, or depend on, control flow that is far
away in the same function.

Of course, the size of the displayed context can be controlled with the
"-U" option anyway, but such fixed-size contexts are usually either too
small, or too large, in the above scenario.

It turns out that "--function-context" does not work correctly for C
source files in edk2. In particular, labels for the goto instruction
(which the edk2 coding style places in the leftmost column) appear to
terminate "--function-context".

The "git" utility contains built-in hunk header patterns for the C and C++
languages. However, they do not take effect in edk2 because we don't
explicitly assign the "cpp" git-diff driver to our C files. The
gitattributes(5) manual explains that this is required:

>            There are a few built-in patterns to make this easier, and
>            tex is one of them, so you do not have to write the above in
>            your configuration file (you still need to enable this with
>            the attribute mechanism, via .gitattributes). The following
>            built in patterns are available:
>
>            [...]
>
>            *   cpp suitable for source code in the C and C++
>                languages.

The key statement is the one in parentheses.

Grab the suffix lists from the [C-Code-File] and [Acpi-Table-Code-File]
sections of "BaseTools/Conf/build_rule.template", add "*.h" and "*.H", and
mark those as belonging to the "cpp" git-diff driver.

This change has a dramatic effect on the following command, for example:

$ git show -W 2ef0c27cb84c

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---

Notes:
    v2:
    
    - take suffixes from "BaseTools/Conf/build_rule.template" [Leif]
    
    - replace "*.h" / "*.c" in the commit message with "C source" and
      [C-Code-File] / [Acpi-Table-Code-File]
    
    - Supersedes: <20200116184929.18020-1-lersek@redhat.com>
      http://mid.mail-archive.com/20200116184929.18020-1-lersek@redhat.com
      https://edk2.groups.io/g/devel/message/53312

 BaseTools/Conf/gitattributes | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/BaseTools/Conf/gitattributes b/BaseTools/Conf/gitattributes
index 58b93e9d4c27..319e89064133 100644
--- a/BaseTools/Conf/gitattributes
+++ b/BaseTools/Conf/gitattributes
@@ -17,3 +17,14 @@
 *.fdf     diff=ini
 *.fdf.inc diff=ini
 *.inf     diff=ini
+*.c       diff=cpp
+*.C       diff=cpp
+*.cc      diff=cpp
+*.CC      diff=cpp
+*.cpp     diff=cpp
+*.Cpp     diff=cpp
+*.CPP     diff=cpp
+*.aslc    diff=cpp
+*.act     diff=cpp
+*.h       diff=cpp
+*.H       diff=cpp
-- 
2.19.1.3.g30247aa5d201

Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Leif Lindholm]

On Mon, Jan 20, 2020 at 10:42:45 +0100, Laszlo Ersek wrote:
> The "--function-context" ("-W") option of git-diff displays the entire
> body of a modified function, not just small modified hunks within the
> function. It is useful for reviewers when the code changes to the function
> are small, but they could affect, or depend on, control flow that is far
> away in the same function.
> 
> Of course, the size of the displayed context can be controlled with the
> "-U" option anyway, but such fixed-size contexts are usually either too
> small, or too large, in the above scenario.
> 
> It turns out that "--function-context" does not work correctly for C
> source files in edk2. In particular, labels for the goto instruction
> (which the edk2 coding style places in the leftmost column) appear to
> terminate "--function-context".
> 
> The "git" utility contains built-in hunk header patterns for the C and C++
> languages. However, they do not take effect in edk2 because we don't
> explicitly assign the "cpp" git-diff driver to our C files. The
> gitattributes(5) manual explains that this is required:
> 
> >            There are a few built-in patterns to make this easier, and
> >            tex is one of them, so you do not have to write the above in
> >            your configuration file (you still need to enable this with
> >            the attribute mechanism, via .gitattributes). The following
> >            built in patterns are available:
> >
> >            [...]
> >
> >            *   cpp suitable for source code in the C and C++
> >                languages.
> 
> The key statement is the one in parentheses.
> 
> Grab the suffix lists from the [C-Code-File] and [Acpi-Table-Code-File]
> sections of "BaseTools/Conf/build_rule.template", add "*.h" and "*.H", and
> mark those as belonging to the "cpp" git-diff driver.
> 
> This change has a dramatic effect on the following command, for example:
> 
> $ git show -W 2ef0c27cb84c
> 
> Cc: Bob Feng <bob.c.feng@intel.com>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Liming Gao <liming.gao@intel.com>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Leif Lindholm <leif@nuviainc.com>
also
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
(if it jars too much to use a different one from Cc: tag above)

For other purposes, the Linaro address can now be considered retired.

/
    Leif

> ---
> 
> Notes:
>     v2:
>     
>     - take suffixes from "BaseTools/Conf/build_rule.template" [Leif]
>     
>     - replace "*.h" / "*.c" in the commit message with "C source" and
>       [C-Code-File] / [Acpi-Table-Code-File]
>     
>     - Supersedes: <20200116184929.18020-1-lersek@redhat.com>
>       http://mid.mail-archive.com/20200116184929.18020-1-lersek@redhat.com
>       https://edk2.groups.io/g/devel/message/53312
> 
>  BaseTools/Conf/gitattributes | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/BaseTools/Conf/gitattributes b/BaseTools/Conf/gitattributes
> index 58b93e9d4c27..319e89064133 100644
> --- a/BaseTools/Conf/gitattributes
> +++ b/BaseTools/Conf/gitattributes
> @@ -17,3 +17,14 @@
>  *.fdf     diff=ini
>  *.fdf.inc diff=ini
>  *.inf     diff=ini
> +*.c       diff=cpp
> +*.C       diff=cpp
> +*.cc      diff=cpp
> +*.CC      diff=cpp
> +*.cpp     diff=cpp
> +*.Cpp     diff=cpp
> +*.CPP     diff=cpp
> +*.aslc    diff=cpp
> +*.act     diff=cpp
> +*.h       diff=cpp
> +*.H       diff=cpp
> -- 
> 2.19.1.3.g30247aa5d201
> 
> 
> 
> 

Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Laszlo Ersek]

On 01/20/20 11:12, Leif Lindholm wrote:
> On Mon, Jan 20, 2020 at 10:42:45 +0100, Laszlo Ersek wrote:
>> The "--function-context" ("-W") option of git-diff displays the entire
>> body of a modified function, not just small modified hunks within the
>> function. It is useful for reviewers when the code changes to the function
>> are small, but they could affect, or depend on, control flow that is far
>> away in the same function.
>>
>> Of course, the size of the displayed context can be controlled with the
>> "-U" option anyway, but such fixed-size contexts are usually either too
>> small, or too large, in the above scenario.
>>
>> It turns out that "--function-context" does not work correctly for C
>> source files in edk2. In particular, labels for the goto instruction
>> (which the edk2 coding style places in the leftmost column) appear to
>> terminate "--function-context".
>>
>> The "git" utility contains built-in hunk header patterns for the C and C++
>> languages. However, they do not take effect in edk2 because we don't
>> explicitly assign the "cpp" git-diff driver to our C files. The
>> gitattributes(5) manual explains that this is required:
>>
>>>            There are a few built-in patterns to make this easier, and
>>>            tex is one of them, so you do not have to write the above in
>>>            your configuration file (you still need to enable this with
>>>            the attribute mechanism, via .gitattributes). The following
>>>            built in patterns are available:
>>>
>>>            [...]
>>>
>>>            *   cpp suitable for source code in the C and C++
>>>                languages.
>>
>> The key statement is the one in parentheses.
>>
>> Grab the suffix lists from the [C-Code-File] and [Acpi-Table-Code-File]
>> sections of "BaseTools/Conf/build_rule.template", add "*.h" and "*.H", and
>> mark those as belonging to the "cpp" git-diff driver.
>>
>> This change has a dramatic effect on the following command, for example:
>>
>> $ git show -W 2ef0c27cb84c
>>
>> Cc: Bob Feng <bob.c.feng@intel.com>
>> Cc: Leif Lindholm <leif.lindholm@linaro.org>
>> Cc: Liming Gao <liming.gao@intel.com>
>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> 
> Reviewed-by: Leif Lindholm <leif@nuviainc.com>

Thanks!

> also
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
> (if it jars too much to use a different one from Cc: tag above)
> 
> For other purposes, the Linaro address can now be considered retired.

Ah yes, sorry about not updating the CC tag with the v1->v2 rebase!

(Because, I had updated even my text editor shortcut that inserts your
name+email!)

Thanks!
Laszlo

Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Laszlo Ersek]

Mike,

can you please ACK this patch while Liming and Bob are away? It's very
simple.

Thanks!
Laszlo

On 01/20/20 10:42, Laszlo Ersek wrote:
> The "--function-context" ("-W") option of git-diff displays the entire
> body of a modified function, not just small modified hunks within the
> function. It is useful for reviewers when the code changes to the function
> are small, but they could affect, or depend on, control flow that is far
> away in the same function.
> 
> Of course, the size of the displayed context can be controlled with the
> "-U" option anyway, but such fixed-size contexts are usually either too
> small, or too large, in the above scenario.
> 
> It turns out that "--function-context" does not work correctly for C
> source files in edk2. In particular, labels for the goto instruction
> (which the edk2 coding style places in the leftmost column) appear to
> terminate "--function-context".
> 
> The "git" utility contains built-in hunk header patterns for the C and C++
> languages. However, they do not take effect in edk2 because we don't
> explicitly assign the "cpp" git-diff driver to our C files. The
> gitattributes(5) manual explains that this is required:
> 
>>            There are a few built-in patterns to make this easier, and
>>            tex is one of them, so you do not have to write the above in
>>            your configuration file (you still need to enable this with
>>            the attribute mechanism, via .gitattributes). The following
>>            built in patterns are available:
>>
>>            [...]
>>
>>            *   cpp suitable for source code in the C and C++
>>                languages.
> 
> The key statement is the one in parentheses.
> 
> Grab the suffix lists from the [C-Code-File] and [Acpi-Table-Code-File]
> sections of "BaseTools/Conf/build_rule.template", add "*.h" and "*.H", and
> mark those as belonging to the "cpp" git-diff driver.
> 
> This change has a dramatic effect on the following command, for example:
> 
> $ git show -W 2ef0c27cb84c
> 
> Cc: Bob Feng <bob.c.feng@intel.com>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Liming Gao <liming.gao@intel.com>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
> 
> Notes:
>     v2:
>     
>     - take suffixes from "BaseTools/Conf/build_rule.template" [Leif]
>     
>     - replace "*.h" / "*.c" in the commit message with "C source" and
>       [C-Code-File] / [Acpi-Table-Code-File]
>     
>     - Supersedes: <20200116184929.18020-1-lersek@redhat.com>
>       http://mid.mail-archive.com/20200116184929.18020-1-lersek@redhat.com
>       https://edk2.groups.io/g/devel/message/53312
> 
>  BaseTools/Conf/gitattributes | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/BaseTools/Conf/gitattributes b/BaseTools/Conf/gitattributes
> index 58b93e9d4c27..319e89064133 100644
> --- a/BaseTools/Conf/gitattributes
> +++ b/BaseTools/Conf/gitattributes
> @@ -17,3 +17,14 @@
>  *.fdf     diff=ini
>  *.fdf.inc diff=ini
>  *.inf     diff=ini
> +*.c       diff=cpp
> +*.C       diff=cpp
> +*.cc      diff=cpp
> +*.CC      diff=cpp
> +*.cpp     diff=cpp
> +*.Cpp     diff=cpp
> +*.CPP     diff=cpp
> +*.aslc    diff=cpp
> +*.act     diff=cpp
> +*.h       diff=cpp
> +*.H       diff=cpp
> 

Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Laszlo Ersek]

Hi Mike,

On 01/23/20 13:13, Laszlo Ersek wrote:
> Mike,
> 
> can you please ACK this patch while Liming and Bob are away? It's very
> simple.

I intended to write "ping" here... But then I realized I failed to add
you to the "To:" list in the first place, when I asked you to review! :(

Sigh.

So, can you please review this now? :)

Thanks
Laszlo

> On 01/20/20 10:42, Laszlo Ersek wrote:
>> The "--function-context" ("-W") option of git-diff displays the entire
>> body of a modified function, not just small modified hunks within the
>> function. It is useful for reviewers when the code changes to the function
>> are small, but they could affect, or depend on, control flow that is far
>> away in the same function.
>>
>> Of course, the size of the displayed context can be controlled with the
>> "-U" option anyway, but such fixed-size contexts are usually either too
>> small, or too large, in the above scenario.
>>
>> It turns out that "--function-context" does not work correctly for C
>> source files in edk2. In particular, labels for the goto instruction
>> (which the edk2 coding style places in the leftmost column) appear to
>> terminate "--function-context".
>>
>> The "git" utility contains built-in hunk header patterns for the C and C++
>> languages. However, they do not take effect in edk2 because we don't
>> explicitly assign the "cpp" git-diff driver to our C files. The
>> gitattributes(5) manual explains that this is required:
>>
>>>            There are a few built-in patterns to make this easier, and
>>>            tex is one of them, so you do not have to write the above in
>>>            your configuration file (you still need to enable this with
>>>            the attribute mechanism, via .gitattributes). The following
>>>            built in patterns are available:
>>>
>>>            [...]
>>>
>>>            *   cpp suitable for source code in the C and C++
>>>                languages.
>>
>> The key statement is the one in parentheses.
>>
>> Grab the suffix lists from the [C-Code-File] and [Acpi-Table-Code-File]
>> sections of "BaseTools/Conf/build_rule.template", add "*.h" and "*.H", and
>> mark those as belonging to the "cpp" git-diff driver.
>>
>> This change has a dramatic effect on the following command, for example:
>>
>> $ git show -W 2ef0c27cb84c
>>
>> Cc: Bob Feng <bob.c.feng@intel.com>
>> Cc: Leif Lindholm <leif.lindholm@linaro.org>
>> Cc: Liming Gao <liming.gao@intel.com>
>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>> ---
>>
>> Notes:
>>     v2:
>>     
>>     - take suffixes from "BaseTools/Conf/build_rule.template" [Leif]
>>     
>>     - replace "*.h" / "*.c" in the commit message with "C source" and
>>       [C-Code-File] / [Acpi-Table-Code-File]
>>     
>>     - Supersedes: <20200116184929.18020-1-lersek@redhat.com>
>>       http://mid.mail-archive.com/20200116184929.18020-1-lersek@redhat.com
>>       https://edk2.groups.io/g/devel/message/53312
>>
>>  BaseTools/Conf/gitattributes | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/BaseTools/Conf/gitattributes b/BaseTools/Conf/gitattributes
>> index 58b93e9d4c27..319e89064133 100644
>> --- a/BaseTools/Conf/gitattributes
>> +++ b/BaseTools/Conf/gitattributes
>> @@ -17,3 +17,14 @@
>>  *.fdf     diff=ini
>>  *.fdf.inc diff=ini
>>  *.inf     diff=ini
>> +*.c       diff=cpp
>> +*.C       diff=cpp
>> +*.cc      diff=cpp
>> +*.CC      diff=cpp
>> +*.cpp     diff=cpp
>> +*.Cpp     diff=cpp
>> +*.CPP     diff=cpp
>> +*.aslc    diff=cpp
>> +*.act     diff=cpp
>> +*.h       diff=cpp
>> +*.H       diff=cpp
>>
> 

Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Liming Gao]

Laszlo:
  I am back. This change is good. Reviewed-by: Liming Gao <liming.gao@intel.com>

Thanks
Liming
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Laszlo Ersek
> Sent: Friday, January 31, 2020 4:34 PM
> To: Kinney, Michael D <michael.d.kinney@intel.com>
> Cc: edk2-devel-groups-io <devel@edk2.groups.io>; Feng, Bob C <bob.c.feng@intel.com>; Leif Lindholm <leif.lindholm@linaro.org>;
> Gao, Liming <liming.gao@intel.com>
> Subject: Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code
> 
> Hi Mike,
> 
> On 01/23/20 13:13, Laszlo Ersek wrote:
> > Mike,
> >
> > can you please ACK this patch while Liming and Bob are away? It's very
> > simple.
> 
> I intended to write "ping" here... But then I realized I failed to add
> you to the "To:" list in the first place, when I asked you to review! :(
> 
> Sigh.
> 
> So, can you please review this now? :)
> 
> Thanks
> Laszlo
> 
> > On 01/20/20 10:42, Laszlo Ersek wrote:
> >> The "--function-context" ("-W") option of git-diff displays the entire
> >> body of a modified function, not just small modified hunks within the
> >> function. It is useful for reviewers when the code changes to the function
> >> are small, but they could affect, or depend on, control flow that is far
> >> away in the same function.
> >>
> >> Of course, the size of the displayed context can be controlled with the
> >> "-U" option anyway, but such fixed-size contexts are usually either too
> >> small, or too large, in the above scenario.
> >>
> >> It turns out that "--function-context" does not work correctly for C
> >> source files in edk2. In particular, labels for the goto instruction
> >> (which the edk2 coding style places in the leftmost column) appear to
> >> terminate "--function-context".
> >>
> >> The "git" utility contains built-in hunk header patterns for the C and C++
> >> languages. However, they do not take effect in edk2 because we don't
> >> explicitly assign the "cpp" git-diff driver to our C files. The
> >> gitattributes(5) manual explains that this is required:
> >>
> >>>            There are a few built-in patterns to make this easier, and
> >>>            tex is one of them, so you do not have to write the above in
> >>>            your configuration file (you still need to enable this with
> >>>            the attribute mechanism, via .gitattributes). The following
> >>>            built in patterns are available:
> >>>
> >>>            [...]
> >>>
> >>>            *   cpp suitable for source code in the C and C++
> >>>                languages.
> >>
> >> The key statement is the one in parentheses.
> >>
> >> Grab the suffix lists from the [C-Code-File] and [Acpi-Table-Code-File]
> >> sections of "BaseTools/Conf/build_rule.template", add "*.h" and "*.H", and
> >> mark those as belonging to the "cpp" git-diff driver.
> >>
> >> This change has a dramatic effect on the following command, for example:
> >>
> >> $ git show -W 2ef0c27cb84c
> >>
> >> Cc: Bob Feng <bob.c.feng@intel.com>
> >> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> >> Cc: Liming Gao <liming.gao@intel.com>
> >> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> >> ---
> >>
> >> Notes:
> >>     v2:
> >>
> >>     - take suffixes from "BaseTools/Conf/build_rule.template" [Leif]
> >>
> >>     - replace "*.h" / "*.c" in the commit message with "C source" and
> >>       [C-Code-File] / [Acpi-Table-Code-File]
> >>
> >>     - Supersedes: <20200116184929.18020-1-lersek@redhat.com>
> >>       http://mid.mail-archive.com/20200116184929.18020-1-lersek@redhat.com
> >>       https://edk2.groups.io/g/devel/message/53312
> >>
> >>  BaseTools/Conf/gitattributes | 11 +++++++++++
> >>  1 file changed, 11 insertions(+)
> >>
> >> diff --git a/BaseTools/Conf/gitattributes b/BaseTools/Conf/gitattributes
> >> index 58b93e9d4c27..319e89064133 100644
> >> --- a/BaseTools/Conf/gitattributes
> >> +++ b/BaseTools/Conf/gitattributes
> >> @@ -17,3 +17,14 @@
> >>  *.fdf     diff=ini
> >>  *.fdf.inc diff=ini
> >>  *.inf     diff=ini
> >> +*.c       diff=cpp
> >> +*.C       diff=cpp
> >> +*.cc      diff=cpp
> >> +*.CC      diff=cpp
> >> +*.cpp     diff=cpp
> >> +*.Cpp     diff=cpp
> >> +*.CPP     diff=cpp
> >> +*.aslc    diff=cpp
> >> +*.act     diff=cpp
> >> +*.h       diff=cpp
> >> +*.H       diff=cpp
> >>
> >
> 
> 
> 

Re: [edk2-devel] [PATCH v2] BaseTools/Conf/gitattributes: fix "--function-context" for C source code

[Laszlo Ersek]

On 01/31/20 09:35, Liming Gao wrote:
> Laszlo:
>   I am back. This change is good. Reviewed-by: Liming Gao <liming.gao@intel.com>

Thank you, Liming!

Merged via <https://github.com/tianocore/edk2/pull/325>: commit
eafd990f2606.

Laszlo