[dpdk-dev] checkpatch: re-enable warnings about split long strings

Message ID 20170929153749.9806-1-stephen@networkplumber.org
State Changes Requested, archived
Delegated to: Thomas Monjalon
Headers show

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Context Check Description
ci/Intel-compilation fail apply issues
ci/checkpatch success coding style OK

Commit Message

Stephen Hemminger Sept. 29, 2017, 3:37 p.m.
The Linux kernel style policy about strings is that strings should
be always put on one line. This makes sense since a typical use
case is for a user to type the error message into a search engine
or grep, and it won't be found if split across lines.
This patch just re-enables that check.

Yes, lots of DPDK code now splits strings, that doesn't
make it right.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
---
 devtools/checkpatches.sh | 1 -
 1 file changed, 1 deletion(-)

Comments

Luca Boccassi Oct. 2, 2017, 10:01 a.m. | #1
On Fri, 2017-09-29 at 08:37 -0700, Stephen Hemminger wrote:
> The Linux kernel style policy about strings is that strings should
> be always put on one line. This makes sense since a typical use
> case is for a user to type the error message into a search engine
> or grep, and it won't be found if split across lines.
> This patch just re-enables that check.
> 
> Yes, lots of DPDK code now splits strings, that doesn't
> make it right.
> 
> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
> ---
>  devtools/checkpatches.sh | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> index a56c41a301c0..3e6081dd673e 100755
> --- a/devtools/checkpatches.sh
> +++ b/devtools/checkpatches.sh
> @@ -44,7 +44,6 @@ options="$options --show-types"
>  options="$options --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
>  VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
>  PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
> -SPLIT_STRING,LONG_LINE_STRING,\
>  LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
>  NEW_TYPEDEFS,COMPARISON_TO_NULL"
>  

Acked-by: Luca Boccassi <bluca@debian.org>

+1 - being able to reliably Google/grep across such a large code base
is extremely useful
Adrien Mazarguil Oct. 2, 2017, 11:53 a.m. | #2
Hi Stephen,

On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
> The Linux kernel style policy about strings is that strings should
> be always put on one line. This makes sense since a typical use
> case is for a user to type the error message into a search engine
> or grep, and it won't be found if split across lines.
> This patch just re-enables that check.
> 
> Yes, lots of DPDK code now splits strings, that doesn't
> make it right.
> 
> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
> ---
>  devtools/checkpatches.sh | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> index a56c41a301c0..3e6081dd673e 100755
> --- a/devtools/checkpatches.sh
> +++ b/devtools/checkpatches.sh
> @@ -44,7 +44,6 @@ options="$options --show-types"
>  options="$options --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
>  VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
>  PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
> -SPLIT_STRING,LONG_LINE_STRING,\
>  LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
>  NEW_TYPEDEFS,COMPARISON_TO_NULL"

I'm not sure, given that the main reason for splitting strings in the first
place is to avoid LONG_LINE_STRING warnings, I think we must choose between
the two options. If split strings are not allowed, then long lines must be.

Since checkpatches.sh is used by various automated scripts to complain
loudly about problems in submissions, the above change prevents maintainers
from writing long string at all (can't split and can't go past 80 columns).

As a result, they will be tempted to cripple their code with nasty
workarounds to shut up checkpatches.sh, we don't want that to happen.

Also I think the reasons stated by original commit cf75514c8e2e are still
relevant. My vote would be to keep things as is.
Bruce Richardson Oct. 2, 2017, 1:46 p.m. | #3
On Mon, Oct 02, 2017 at 01:53:17PM +0200, Adrien Mazarguil wrote:
> Hi Stephen,
> 
> On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
> > The Linux kernel style policy about strings is that strings should
> > be always put on one line. This makes sense since a typical use case
> > is for a user to type the error message into a search engine or
> > grep, and it won't be found if split across lines.  This patch just
> > re-enables that check.
> > 
> > Yes, lots of DPDK code now splits strings, that doesn't make it
> > right.
> > 
> > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> ---
> > devtools/checkpatches.sh | 1 - 1 file changed, 1 deletion(-)
> > 
> > diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> > index a56c41a301c0..3e6081dd673e 100755 ---
> > a/devtools/checkpatches.sh +++ b/devtools/checkpatches.sh @@ -44,7
> > +44,6 @@ options="$options --show-types" options="$options
> > --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
> > VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
> > PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
> > -SPLIT_STRING,LONG_LINE_STRING,\
> > LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
> > NEW_TYPEDEFS,COMPARISON_TO_NULL"
> 
> I'm not sure, given that the main reason for splitting strings in the
> first place is to avoid LONG_LINE_STRING warnings, I think we must
> choose between the two options. If split strings are not allowed, then
> long lines must be.
> 
> Since checkpatches.sh is used by various automated scripts to complain
> loudly about problems in submissions, the above change prevents
> maintainers from writing long string at all (can't split and can't go
> past 80 columns).
> 
> As a result, they will be tempted to cripple their code with nasty
> workarounds to shut up checkpatches.sh, we don't want that to happen.
> 
> Also I think the reasons stated by original commit cf75514c8e2e are
> still relevant. My vote would be to keep things as is.
> 
In my experience, checkpatch is smart enough to recognise when a long
line overflows the 80 character limit because of a single long string,
so the two options are not mutually exclusive. In other words, long
lines are not allowed except in the case where shortening the line
involves splitting a string. There may be a small amount of work in
getting checkpatch happy, i.e. by putting the string on a line on it's
own, but we can indeed have our cake and eat it too in this case.

/Bruce
Adrien Mazarguil Oct. 2, 2017, 4:21 p.m. | #4
On Mon, Oct 02, 2017 at 02:46:24PM +0100, Bruce Richardson wrote:
> On Mon, Oct 02, 2017 at 01:53:17PM +0200, Adrien Mazarguil wrote:
> > Hi Stephen,
> > 
> > On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
> > > The Linux kernel style policy about strings is that strings should
> > > be always put on one line. This makes sense since a typical use case
> > > is for a user to type the error message into a search engine or
> > > grep, and it won't be found if split across lines.  This patch just
> > > re-enables that check.
> > > 
> > > Yes, lots of DPDK code now splits strings, that doesn't make it
> > > right.
> > > 
> > > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> ---
> > > devtools/checkpatches.sh | 1 - 1 file changed, 1 deletion(-)
> > > 
> > > diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> > > index a56c41a301c0..3e6081dd673e 100755 ---
> > > a/devtools/checkpatches.sh +++ b/devtools/checkpatches.sh @@ -44,7
> > > +44,6 @@ options="$options --show-types" options="$options
> > > --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
> > > VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
> > > PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
> > > -SPLIT_STRING,LONG_LINE_STRING,\
> > > LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
> > > NEW_TYPEDEFS,COMPARISON_TO_NULL"
> > 
> > I'm not sure, given that the main reason for splitting strings in the
> > first place is to avoid LONG_LINE_STRING warnings, I think we must
> > choose between the two options. If split strings are not allowed, then
> > long lines must be.
> > 
> > Since checkpatches.sh is used by various automated scripts to complain
> > loudly about problems in submissions, the above change prevents
> > maintainers from writing long string at all (can't split and can't go
> > past 80 columns).
> > 
> > As a result, they will be tempted to cripple their code with nasty
> > workarounds to shut up checkpatches.sh, we don't want that to happen.
> > 
> > Also I think the reasons stated by original commit cf75514c8e2e are
> > still relevant. My vote would be to keep things as is.
> > 
> In my experience, checkpatch is smart enough to recognise when a long
> line overflows the 80 character limit because of a single long string,
> so the two options are not mutually exclusive. In other words, long
> lines are not allowed except in the case where shortening the line
> involves splitting a string. There may be a small amount of work in
> getting checkpatch happy, i.e. by putting the string on a line on it's
> own, but we can indeed have our cake and eat it too in this case.

I can't seem to get around warnings without ignoring either SPLIT_STRING or
LONG_LINE_STRING as of Linux v4.14-rc3's checkpatch.pl. I think you can only
get around them by fooling it somehow. You really need to ignore at least
LONG_LINE_STRING to meet the requirements of the commit log.

However SPLIT_STRING still looks necessary to address part of cf75514c8e2e
("devtools: ignore warning on long log string"):

 "...lines that make use of PRIx64 with string concatenation will still be
  flagged if the beginning of the last string fragment begins after the 80
  character threshold."

It's not all that uncommon in my opinion.
Bruce Richardson Oct. 3, 2017, 10:38 a.m. | #5
On Mon, Oct 02, 2017 at 06:21:06PM +0200, Adrien Mazarguil wrote:
> On Mon, Oct 02, 2017 at 02:46:24PM +0100, Bruce Richardson wrote:
> > On Mon, Oct 02, 2017 at 01:53:17PM +0200, Adrien Mazarguil wrote:
> > > Hi Stephen,
> > > 
> > > On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
> > > > The Linux kernel style policy about strings is that strings should
> > > > be always put on one line. This makes sense since a typical use case
> > > > is for a user to type the error message into a search engine or
> > > > grep, and it won't be found if split across lines.  This patch just
> > > > re-enables that check.
> > > > 
> > > > Yes, lots of DPDK code now splits strings, that doesn't make it
> > > > right.
> > > > 
> > > > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> ---
> > > > devtools/checkpatches.sh | 1 - 1 file changed, 1 deletion(-)
> > > > 
> > > > diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> > > > index a56c41a301c0..3e6081dd673e 100755 ---
> > > > a/devtools/checkpatches.sh +++ b/devtools/checkpatches.sh @@ -44,7
> > > > +44,6 @@ options="$options --show-types" options="$options
> > > > --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
> > > > VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
> > > > PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
> > > > -SPLIT_STRING,LONG_LINE_STRING,\
> > > > LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
> > > > NEW_TYPEDEFS,COMPARISON_TO_NULL"
> > > 
> > > I'm not sure, given that the main reason for splitting strings in the
> > > first place is to avoid LONG_LINE_STRING warnings, I think we must
> > > choose between the two options. If split strings are not allowed, then
> > > long lines must be.
> > > 
> > > Since checkpatches.sh is used by various automated scripts to complain
> > > loudly about problems in submissions, the above change prevents
> > > maintainers from writing long string at all (can't split and can't go
> > > past 80 columns).
> > > 
> > > As a result, they will be tempted to cripple their code with nasty
> > > workarounds to shut up checkpatches.sh, we don't want that to happen.
> > > 
> > > Also I think the reasons stated by original commit cf75514c8e2e are
> > > still relevant. My vote would be to keep things as is.
> > > 
> > In my experience, checkpatch is smart enough to recognise when a long
> > line overflows the 80 character limit because of a single long string,
> > so the two options are not mutually exclusive. In other words, long
> > lines are not allowed except in the case where shortening the line
> > involves splitting a string. There may be a small amount of work in
> > getting checkpatch happy, i.e. by putting the string on a line on it's
> > own, but we can indeed have our cake and eat it too in this case.
> 
> I can't seem to get around warnings without ignoring either SPLIT_STRING or
> LONG_LINE_STRING as of Linux v4.14-rc3's checkpatch.pl. I think you can only
> get around them by fooling it somehow. You really need to ignore at least
> LONG_LINE_STRING to meet the requirements of the commit log.
> 
> However SPLIT_STRING still looks necessary to address part of cf75514c8e2e
> ("devtools: ignore warning on long log string"):
> 
>  "...lines that make use of PRIx64 with string concatenation will still be
>   flagged if the beginning of the last string fragment begins after the 80
>   character threshold."
> 
> It's not all that uncommon in my opinion.
> 
If you have PRIx64 in it, it's not part of a literal string you would
grep, so it's reasonable to split there. The user cannot know what the
specific %x formatting character used is.

/Bruce
Adrien Mazarguil Oct. 3, 2017, 10:56 a.m. | #6
On Tue, Oct 03, 2017 at 11:38:13AM +0100, Bruce Richardson wrote:
> On Mon, Oct 02, 2017 at 06:21:06PM +0200, Adrien Mazarguil wrote:
> > On Mon, Oct 02, 2017 at 02:46:24PM +0100, Bruce Richardson wrote:
> > > On Mon, Oct 02, 2017 at 01:53:17PM +0200, Adrien Mazarguil wrote:
> > > > Hi Stephen,
> > > > 
> > > > On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
> > > > > The Linux kernel style policy about strings is that strings should
> > > > > be always put on one line. This makes sense since a typical use case
> > > > > is for a user to type the error message into a search engine or
> > > > > grep, and it won't be found if split across lines.  This patch just
> > > > > re-enables that check.
> > > > > 
> > > > > Yes, lots of DPDK code now splits strings, that doesn't make it
> > > > > right.
> > > > > 
> > > > > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> ---
> > > > > devtools/checkpatches.sh | 1 - 1 file changed, 1 deletion(-)
> > > > > 
> > > > > diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> > > > > index a56c41a301c0..3e6081dd673e 100755 ---
> > > > > a/devtools/checkpatches.sh +++ b/devtools/checkpatches.sh @@ -44,7
> > > > > +44,6 @@ options="$options --show-types" options="$options
> > > > > --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
> > > > > VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
> > > > > PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
> > > > > -SPLIT_STRING,LONG_LINE_STRING,\
> > > > > LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
> > > > > NEW_TYPEDEFS,COMPARISON_TO_NULL"
> > > > 
> > > > I'm not sure, given that the main reason for splitting strings in the
> > > > first place is to avoid LONG_LINE_STRING warnings, I think we must
> > > > choose between the two options. If split strings are not allowed, then
> > > > long lines must be.
> > > > 
> > > > Since checkpatches.sh is used by various automated scripts to complain
> > > > loudly about problems in submissions, the above change prevents
> > > > maintainers from writing long string at all (can't split and can't go
> > > > past 80 columns).
> > > > 
> > > > As a result, they will be tempted to cripple their code with nasty
> > > > workarounds to shut up checkpatches.sh, we don't want that to happen.
> > > > 
> > > > Also I think the reasons stated by original commit cf75514c8e2e are
> > > > still relevant. My vote would be to keep things as is.
> > > > 
> > > In my experience, checkpatch is smart enough to recognise when a long
> > > line overflows the 80 character limit because of a single long string,
> > > so the two options are not mutually exclusive. In other words, long
> > > lines are not allowed except in the case where shortening the line
> > > involves splitting a string. There may be a small amount of work in
> > > getting checkpatch happy, i.e. by putting the string on a line on it's
> > > own, but we can indeed have our cake and eat it too in this case.
> > 
> > I can't seem to get around warnings without ignoring either SPLIT_STRING or
> > LONG_LINE_STRING as of Linux v4.14-rc3's checkpatch.pl. I think you can only
> > get around them by fooling it somehow. You really need to ignore at least
> > LONG_LINE_STRING to meet the requirements of the commit log.
> > 
> > However SPLIT_STRING still looks necessary to address part of cf75514c8e2e
> > ("devtools: ignore warning on long log string"):
> > 
> >  "...lines that make use of PRIx64 with string concatenation will still be
> >   flagged if the beginning of the last string fragment begins after the 80
> >   character threshold."
> > 
> > It's not all that uncommon in my opinion.
> > 
> If you have PRIx64 in it, it's not part of a literal string you would
> grep, so it's reasonable to split there. The user cannot know what the
> specific %x formatting character used is.

I agree, however in that case checkpatch would complain because our
configuration doesn't specify to ignore SPLIT_STRING since there is no comma
separator when concatenating them.

My point is that the occasional exception is still necessary for split
strings, that ignoring LONG_LINE_STRING must remain either way and
unnecessary warnings cause more harm than good (they need to be worked
around if we enforce this rule).

In short, long/split strings acceptability assessment should be left to
reviewers, as it cannot be automated in all cases through checkpatch.pl.
Ferruh Yigit March 28, 2019, 7:02 p.m. | #7
On 10/3/2017 11:56 AM, adrien.mazarguil at 6wind.com (Adrien Mazarguil) wrote:
> On Tue, Oct 03, 2017 at 11:38:13AM +0100, Bruce Richardson wrote:
>> On Mon, Oct 02, 2017 at 06:21:06PM +0200, Adrien Mazarguil wrote:
>>> On Mon, Oct 02, 2017 at 02:46:24PM +0100, Bruce Richardson wrote:
>>>> On Mon, Oct 02, 2017 at 01:53:17PM +0200, Adrien Mazarguil wrote:
>>>>> Hi Stephen,
>>>>>
>>>>> On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
>>>>>> The Linux kernel style policy about strings is that strings should
>>>>>> be always put on one line. This makes sense since a typical use case
>>>>>> is for a user to type the error message into a search engine or
>>>>>> grep, and it won't be found if split across lines.  This patch just
>>>>>> re-enables that check.
>>>>>>
>>>>>> Yes, lots of DPDK code now splits strings, that doesn't make it
>>>>>> right.
>>>>>>
>>>>>> Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com> ---
>>>>>> devtools/checkpatches.sh | 1 - 1 file changed, 1 deletion(-)
>>>>>>
>>>>>> diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
>>>>>> index a56c41a301c0..3e6081dd673e 100755 ---
>>>>>> a/devtools/checkpatches.sh +++ b/devtools/checkpatches.sh @@ -44,7
>>>>>> +44,6 @@ options="$options --show-types" options="$options
>>>>>> --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
>>>>>> VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
>>>>>> PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
>>>>>> -SPLIT_STRING,LONG_LINE_STRING,\
>>>>>> LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
>>>>>> NEW_TYPEDEFS,COMPARISON_TO_NULL"
>>>>>
>>>>> I'm not sure, given that the main reason for splitting strings in the
>>>>> first place is to avoid LONG_LINE_STRING warnings, I think we must
>>>>> choose between the two options. If split strings are not allowed, then
>>>>> long lines must be.
>>>>>
>>>>> Since checkpatches.sh is used by various automated scripts to complain
>>>>> loudly about problems in submissions, the above change prevents
>>>>> maintainers from writing long string at all (can't split and can't go
>>>>> past 80 columns).
>>>>>
>>>>> As a result, they will be tempted to cripple their code with nasty
>>>>> workarounds to shut up checkpatches.sh, we don't want that to happen.
>>>>>
>>>>> Also I think the reasons stated by original commit cf75514c8e2e are
>>>>> still relevant. My vote would be to keep things as is.
>>>>>
>>>> In my experience, checkpatch is smart enough to recognise when a long
>>>> line overflows the 80 character limit because of a single long string,
>>>> so the two options are not mutually exclusive. In other words, long
>>>> lines are not allowed except in the case where shortening the line
>>>> involves splitting a string. There may be a small amount of work in
>>>> getting checkpatch happy, i.e. by putting the string on a line on it's
>>>> own, but we can indeed have our cake and eat it too in this case.
>>>
>>> I can't seem to get around warnings without ignoring either SPLIT_STRING or
>>> LONG_LINE_STRING as of Linux v4.14-rc3's checkpatch.pl. I think you can only
>>> get around them by fooling it somehow. You really need to ignore at least
>>> LONG_LINE_STRING to meet the requirements of the commit log.
>>>
>>> However SPLIT_STRING still looks necessary to address part of cf75514c8e2e
>>> ("devtools: ignore warning on long log string"):
>>>
>>>  "...lines that make use of PRIx64 with string concatenation will still be
>>>   flagged if the beginning of the last string fragment begins after the 80
>>>   character threshold."
>>>
>>> It's not all that uncommon in my opinion.
>>>
>> If you have PRIx64 in it, it's not part of a literal string you would
>> grep, so it's reasonable to split there. The user cannot know what the
>> specific %x formatting character used is.
> 
> I agree, however in that case checkpatch would complain because our
> configuration doesn't specify to ignore SPLIT_STRING since there is no comma
> separator when concatenating them.
> 
> My point is that the occasional exception is still necessary for split
> strings, that ignoring LONG_LINE_STRING must remain either way and
> unnecessary warnings cause more harm than good (they need to be worked
> around if we enforce this rule).
> 
> In short, long/split strings acceptability assessment should be left to
> reviewers, as it cannot be automated in all cases through checkpatch.pl.
> 

This patch is waiting in patchwork for a long time now.

My experience is same with Adrien's, if 'LONG_LINE_STRING' is not ignored, it
will complain about long log messages, so removing 'LONG_LINE_STRING'
contradicts with the reason of the patch described in the commit log.

Perhaps it can be an option to remove only 'SPLIT_STRING' from ignore list, to
detect split messages.

But overall, I am updating this patch as "Change Requested", if there is a
demand for ignoring 'SPLIT_STRING' please send a new version.

Thanks,
ferruh
Ferruh Yigit March 28, 2019, 7:03 p.m. | #8
On 3/28/2019 7:02 PM, Ferruh Yigit wrote:
> On 10/3/2017 11:56 AM, adrien.mazarguil at 6wind.com (Adrien Mazarguil) wrote:
>> On Tue, Oct 03, 2017 at 11:38:13AM +0100, Bruce Richardson wrote:
>>> On Mon, Oct 02, 2017 at 06:21:06PM +0200, Adrien Mazarguil wrote:
>>>> On Mon, Oct 02, 2017 at 02:46:24PM +0100, Bruce Richardson wrote:
>>>>> On Mon, Oct 02, 2017 at 01:53:17PM +0200, Adrien Mazarguil wrote:
>>>>>> Hi Stephen,
>>>>>>
>>>>>> On Fri, Sep 29, 2017 at 08:37:49AM -0700, Stephen Hemminger wrote:
>>>>>>> The Linux kernel style policy about strings is that strings should
>>>>>>> be always put on one line. This makes sense since a typical use case
>>>>>>> is for a user to type the error message into a search engine or
>>>>>>> grep, and it won't be found if split across lines.  This patch just
>>>>>>> re-enables that check.
>>>>>>>
>>>>>>> Yes, lots of DPDK code now splits strings, that doesn't make it
>>>>>>> right.
>>>>>>>
>>>>>>> Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com> ---
>>>>>>> devtools/checkpatches.sh | 1 - 1 file changed, 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
>>>>>>> index a56c41a301c0..3e6081dd673e 100755 ---
>>>>>>> a/devtools/checkpatches.sh +++ b/devtools/checkpatches.sh @@ -44,7
>>>>>>> +44,6 @@ options="$options --show-types" options="$options
>>>>>>> --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
>>>>>>> VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
>>>>>>> PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
>>>>>>> -SPLIT_STRING,LONG_LINE_STRING,\
>>>>>>> LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
>>>>>>> NEW_TYPEDEFS,COMPARISON_TO_NULL"
>>>>>>
>>>>>> I'm not sure, given that the main reason for splitting strings in the
>>>>>> first place is to avoid LONG_LINE_STRING warnings, I think we must
>>>>>> choose between the two options. If split strings are not allowed, then
>>>>>> long lines must be.
>>>>>>
>>>>>> Since checkpatches.sh is used by various automated scripts to complain
>>>>>> loudly about problems in submissions, the above change prevents
>>>>>> maintainers from writing long string at all (can't split and can't go
>>>>>> past 80 columns).
>>>>>>
>>>>>> As a result, they will be tempted to cripple their code with nasty
>>>>>> workarounds to shut up checkpatches.sh, we don't want that to happen.
>>>>>>
>>>>>> Also I think the reasons stated by original commit cf75514c8e2e are
>>>>>> still relevant. My vote would be to keep things as is.
>>>>>>
>>>>> In my experience, checkpatch is smart enough to recognise when a long
>>>>> line overflows the 80 character limit because of a single long string,
>>>>> so the two options are not mutually exclusive. In other words, long
>>>>> lines are not allowed except in the case where shortening the line
>>>>> involves splitting a string. There may be a small amount of work in
>>>>> getting checkpatch happy, i.e. by putting the string on a line on it's
>>>>> own, but we can indeed have our cake and eat it too in this case.
>>>>
>>>> I can't seem to get around warnings without ignoring either SPLIT_STRING or
>>>> LONG_LINE_STRING as of Linux v4.14-rc3's checkpatch.pl. I think you can only
>>>> get around them by fooling it somehow. You really need to ignore at least
>>>> LONG_LINE_STRING to meet the requirements of the commit log.
>>>>
>>>> However SPLIT_STRING still looks necessary to address part of cf75514c8e2e
>>>> ("devtools: ignore warning on long log string"):
>>>>
>>>>  "...lines that make use of PRIx64 with string concatenation will still be
>>>>   flagged if the beginning of the last string fragment begins after the 80
>>>>   character threshold."
>>>>
>>>> It's not all that uncommon in my opinion.
>>>>
>>> If you have PRIx64 in it, it's not part of a literal string you would
>>> grep, so it's reasonable to split there. The user cannot know what the
>>> specific %x formatting character used is.
>>
>> I agree, however in that case checkpatch would complain because our
>> configuration doesn't specify to ignore SPLIT_STRING since there is no comma
>> separator when concatenating them.
>>
>> My point is that the occasional exception is still necessary for split
>> strings, that ignoring LONG_LINE_STRING must remain either way and
>> unnecessary warnings cause more harm than good (they need to be worked
>> around if we enforce this rule).
>>
>> In short, long/split strings acceptability assessment should be left to
>> reviewers, as it cannot be automated in all cases through checkpatch.pl.
>>
> 
> This patch is waiting in patchwork for a long time now.
> 
> My experience is same with Adrien's, if 'LONG_LINE_STRING' is not ignored, it
> will complain about long log messages, so removing 'LONG_LINE_STRING'
> contradicts with the reason of the patch described in the commit log.
> 
> Perhaps it can be an option to remove only 'SPLIT_STRING' from ignore list, to
> detect split messages.
> 
> But overall, I am updating this patch as "Change Requested", if there is a
> demand for ignoring 'SPLIT_STRING' please send a new version.
> 

Sorry for the noise, I keep forgetting this, for reference the patch mentioned:
https://patches.dpdk.org/patch/29438/

Patch

diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
index a56c41a301c0..3e6081dd673e 100755
--- a/devtools/checkpatches.sh
+++ b/devtools/checkpatches.sh
@@ -44,7 +44,6 @@  options="$options --show-types"
 options="$options --ignore=LINUX_VERSION_CODE,FILE_PATH_CHANGES,\
 VOLATILE,PREFER_PACKED,PREFER_ALIGNED,PREFER_PRINTF,\
 PREFER_KERNEL_TYPES,BIT_MACRO,CONST_STRUCT,\
-SPLIT_STRING,LONG_LINE_STRING,\
 LINE_SPACING,PARENTHESIS_ALIGNMENT,NETWORKING_BLOCK_COMMENT_STYLE,\
 NEW_TYPEDEFS,COMPARISON_TO_NULL"