[PATCH] coccinelle: add style check for assignment in if

[PATCH] coccinelle: add style check for assignment in if

[Kris Borer]

Add a semantic patch for fixing some cases of checkpatch.pl error:

ERROR: do not use assignment in if condition

Reviewed-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Kris Borer <kborer@gmail.com>
---
 scripts/coccinelle/style/assignment_in_if.cocci | 92 +++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 scripts/coccinelle/style/assignment_in_if.cocci

diff --git a/scripts/coccinelle/style/assignment_in_if.cocci b/scripts/coccinelle/style/assignment_in_if.cocci
new file mode 100644
index 0000000..22ab161
--- /dev/null
+++ b/scripts/coccinelle/style/assignment_in_if.cocci
@@ -0,0 +1,92 @@
+// find checkpatch.pl errors of the type:
+//	ERROR: do not use assignment in if condition
+//
+// This script is designed to correct code where assignments exist in if
+// conditions. It is only capable of handling a subset of such problems.
+//
+// For example:
+//
+//	if(result = myfun())
+//
+// would become:
+//
+//	result = myfun();
+//	if(result)
+//
+// Confidence: Moderate
+
+
+// if ( ret = call() )
+@if1@
+identifier i;
+expression E;
+statement S1, S2;
+@@
+
++ i = E;
+  if (
+- (i = E)
++ i
+  ) S1 else S2
+
+
+// if ( (ret = call()) < 0 )
+@if2@
+identifier i;
+expression E;
+statement S1, S2;
+binary operator b;
+@@
+
++ i = E;
+  if (
+- (i = E)
++ i
+  b ... ) S1 else S2
+
+// if ( ptr->fun && (ret = ptr->fun()) < 0 )
+@if3@
+identifier i, i2;
+expression E1, E2;
+constant c;
+binary operator b;
+@@
+
++ if( E1->i ) {
++  	i2 = E2;
++ 	if (i2 b c) {
+- if( E1->i && ((i2 = E2) b c) ) {
+  ...
+- }
++ 	}
++ }
+
+// if ( (ret = call()) < 0 && ret != -1 )
+@if4@
+identifier i;
+expression E, E2;
+statement S1, S2;
+binary operator b;
+@@
+
++ i = E;
+  if (
+- (i = E)
++ i
+  b
+  ... && E2 ) S1 else S2
+
+// if ( (ret = call()) < 0 && ret != -1 && ret != -2 )
+@if5@
+identifier i;
+expression E, E2, E3;
+statement S1, S2;
+binary operator b;
+@@
+
++ i = E;
+  if (
+- (i = E)
++ i
+  b
+  ... && E2 && E3 ) S1 else S2
-- 
1.9.1

Re: [PATCH] coccinelle: add style check for assignment in if

[Julia Lawall]

On Sat, 15 Aug 2015, Kris Borer wrote:

> Add a semantic patch for fixing some cases of checkpatch.pl error:
> 
> ERROR: do not use assignment in if condition
> 
> Reviewed-by: Julia Lawall <julia.lawall@lip6.fr>

Sorry, but I'm not done reviewing it.  I have a lot of changes to propose.  
Is this different than the RFC v2?

julia

> Signed-off-by: Kris Borer <kborer@gmail.com>
> ---
>  scripts/coccinelle/style/assignment_in_if.cocci | 92 +++++++++++++++++++++++++
>  1 file changed, 92 insertions(+)
>  create mode 100644 scripts/coccinelle/style/assignment_in_if.cocci
> 
> diff --git a/scripts/coccinelle/style/assignment_in_if.cocci b/scripts/coccinelle/style/assignment_in_if.cocci
> new file mode 100644
> index 0000000..22ab161
> --- /dev/null
> +++ b/scripts/coccinelle/style/assignment_in_if.cocci
> @@ -0,0 +1,92 @@
> +// find checkpatch.pl errors of the type:
> +//	ERROR: do not use assignment in if condition
> +//
> +// This script is designed to correct code where assignments exist in if
> +// conditions. It is only capable of handling a subset of such problems.
> +//
> +// For example:
> +//
> +//	if(result = myfun())
> +//
> +// would become:
> +//
> +//	result = myfun();
> +//	if(result)
> +//
> +// Confidence: Moderate
> +
> +
> +// if ( ret = call() )
> +@if1@
> +identifier i;
> +expression E;
> +statement S1, S2;
> +@@
> +
> ++ i = E;
> +  if (
> +- (i = E)
> ++ i
> +  ) S1 else S2
> +
> +
> +// if ( (ret = call()) < 0 )
> +@if2@
> +identifier i;
> +expression E;
> +statement S1, S2;
> +binary operator b;
> +@@
> +
> ++ i = E;
> +  if (
> +- (i = E)
> ++ i
> +  b ... ) S1 else S2
> +
> +// if ( ptr->fun && (ret = ptr->fun()) < 0 )
> +@if3@
> +identifier i, i2;
> +expression E1, E2;
> +constant c;
> +binary operator b;
> +@@
> +
> ++ if( E1->i ) {
> ++  	i2 = E2;
> ++ 	if (i2 b c) {
> +- if( E1->i && ((i2 = E2) b c) ) {
> +  ...
> +- }
> ++ 	}
> ++ }
> +
> +// if ( (ret = call()) < 0 && ret != -1 )
> +@if4@
> +identifier i;
> +expression E, E2;
> +statement S1, S2;
> +binary operator b;
> +@@
> +
> ++ i = E;
> +  if (
> +- (i = E)
> ++ i
> +  b
> +  ... && E2 ) S1 else S2
> +
> +// if ( (ret = call()) < 0 && ret != -1 && ret != -2 )
> +@if5@
> +identifier i;
> +expression E, E2, E3;
> +statement S1, S2;
> +binary operator b;
> +@@
> +
> ++ i = E;
> +  if (
> +- (i = E)
> ++ i
> +  b
> +  ... && E2 && E3 ) S1 else S2
> -- 
> 1.9.1
> 
> 

Re: [PATCH] coccinelle: add style check for assignment in if

[Kris Borer]

I apologize, I misunderstood your email. It is the same as RFC v2.

On Sat, Aug 15, 2015 at 1:30 PM, Julia Lawall <julia.lawall@lip6.fr> wrote:
>
>
> On Sat, 15 Aug 2015, Kris Borer wrote:
>
>> Add a semantic patch for fixing some cases of checkpatch.pl error:
>>
>> ERROR: do not use assignment in if condition
>>
>> Reviewed-by: Julia Lawall <julia.lawall@lip6.fr>
>
> Sorry, but I'm not done reviewing it.  I have a lot of changes to propose.
> Is this different than the RFC v2?
>
> julia
>
>> Signed-off-by: Kris Borer <kborer@gmail.com>
>> ---
>>  scripts/coccinelle/style/assignment_in_if.cocci | 92 +++++++++++++++++++++++++
>>  1 file changed, 92 insertions(+)
>>  create mode 100644 scripts/coccinelle/style/assignment_in_if.cocci
>>
>> diff --git a/scripts/coccinelle/style/assignment_in_if.cocci b/scripts/coccinelle/style/assignment_in_if.cocci
>> new file mode 100644
>> index 0000000..22ab161
>> --- /dev/null
>> +++ b/scripts/coccinelle/style/assignment_in_if.cocci
>> @@ -0,0 +1,92 @@
>> +// find checkpatch.pl errors of the type:
>> +//   ERROR: do not use assignment in if condition
>> +//
>> +// This script is designed to correct code where assignments exist in if
>> +// conditions. It is only capable of handling a subset of such problems.
>> +//
>> +// For example:
>> +//
>> +//   if(result = myfun())
>> +//
>> +// would become:
>> +//
>> +//   result = myfun();
>> +//   if(result)
>> +//
>> +// Confidence: Moderate
>> +
>> +
>> +// if ( ret = call() )
>> +@if1@
>> +identifier i;
>> +expression E;
>> +statement S1, S2;
>> +@@
>> +
>> ++ i = E;
>> +  if (
>> +- (i = E)
>> ++ i
>> +  ) S1 else S2
>> +
>> +
>> +// if ( (ret = call()) < 0 )
>> +@if2@
>> +identifier i;
>> +expression E;
>> +statement S1, S2;
>> +binary operator b;
>> +@@
>> +
>> ++ i = E;
>> +  if (
>> +- (i = E)
>> ++ i
>> +  b ... ) S1 else S2
>> +
>> +// if ( ptr->fun && (ret = ptr->fun()) < 0 )
>> +@if3@
>> +identifier i, i2;
>> +expression E1, E2;
>> +constant c;
>> +binary operator b;
>> +@@
>> +
>> ++ if( E1->i ) {
>> ++    i2 = E2;
>> ++    if (i2 b c) {
>> +- if( E1->i && ((i2 = E2) b c) ) {
>> +  ...
>> +- }
>> ++    }
>> ++ }
>> +
>> +// if ( (ret = call()) < 0 && ret != -1 )
>> +@if4@
>> +identifier i;
>> +expression E, E2;
>> +statement S1, S2;
>> +binary operator b;
>> +@@
>> +
>> ++ i = E;
>> +  if (
>> +- (i = E)
>> ++ i
>> +  b
>> +  ... && E2 ) S1 else S2
>> +
>> +// if ( (ret = call()) < 0 && ret != -1 && ret != -2 )
>> +@if5@
>> +identifier i;
>> +expression E, E2, E3;
>> +statement S1, S2;
>> +binary operator b;
>> +@@
>> +
>> ++ i = E;
>> +  if (
>> +- (i = E)
>> ++ i
>> +  b
>> +  ... && E2 && E3 ) S1 else S2
>> --
>> 1.9.1
>>
>>

Re: [PATCH] coccinelle: add style check for assignment in if

[Julia Lawall]

My version is below.  It adds parentheses in a few more places, and allows 
assignments without a binary operator (b) in the && cases.

Also I threw in a case for things like: if (ret = -ENOENT, !data)

Another thing is that the header is not really correct.  It should be in 
the following format:

/// Short comment of gernal interest
//# More information, eg about potential false positives
///
// Confidence: Moderate
// Copyright: whatever you want, it would be nice to have your name
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: --no-includes --include-headers

Then you should have:

virtual patch

Otherwise, the kernel infrastructure will not think that the patch mode is 
supported.  No other changes are needed, since no other modes are 
supported.  I don't think that supporting other modes is necessary, since 
I think that checkpatch complains about this issue too.

julia

------------------------

// find checkpatch.pl errors of the type:
//	ERROR: do not use assignment in if condition
//
// This script is designed to correct code where assignments exist in if
// conditions. It is only capable of handling a subset of such problems.
//
// For example:
//
//	if(result = myfun())
//
// would become:
//
//	result = myfun();
//	if(result)
//
// Confidence: Moderate

// if ( (ret = call()) < 0 )
@if2@
expression i;
expression E, E2;
statement S1, S2;
binary operator b;
@@

+ i = E;
  if (
(
  ... b
- (i = E)
+ i
|
- (i = E)
+ i
  b ...
|
- (i = E)
+ i
|
- (i = E),
  E2
)
   ) S1 else S2

// if ( ptr->fun && (ret = ptr->fun()) < 0 )
@if3@
expression i2;
expression E1, E2;
constant c;
binary operator b;
@@

+ if( E1 ) {
+  	i2 = E2;
+ 	if (i2 b c) {
- if( E1 && ((i2 = E2) b c) ) {
  ...
- }
+ 	}
+ }

// if ( (ret = call()) < 0 && ret != -1 )
@if4@
expression i;
expression E, E2;
statement S1, S2;
binary operator b;
@@

+ i = E;
  if (
(
  (...
  b
- (i = E)
+ i
  )
|
  (
- (i = E)
+ i
  b
  ...)
|
- (i = E)
+ i
) && E2 ) S1 else S2

// if ( (ret = call()) < 0 && ret != -1 && ret != -2 )
@if5@
expression i;
expression E, E2, E3;
statement S1, S2;
binary operator b;
@@

+ i = E;
  if (
(
  (...
  b
- (i = E)
+ i
  )
|
  (
- (i = E)
+ i
  b
  ...)
|
- (i = E)
+ i
) && E2 && E3 ) S1 else S2

@@
expression i,e;
statement S1,S2;
@@

if (<+... 
-i = e
+BAD
 ...+>) S1 else S2