checkpatch not warning for some split strings

checkpatch not warning for some split strings

[Joe Perches]

Hey Josh.

Back when you added commit ca56dc098ca
("checkpatch: check for quoted strings broken across lines")

You added this test case:

    Test case:
    
    void context(void)
    {
        struct { unsigned magic; const char *strdata; } foo[] = {
                { 42, "these strings"
                      "do not produce warnings" },
                { 256, "though perhaps"
                       "they should" },
        };

which avoids emitting a warning on split strings across
multiple lines without a function-call like '(' use on
the line above.

Perhaps the "\(" test should be removed as checkpatch
doesn't emit a warning for some uses like:

diff --git a/drivers/net/wireless/iwlwifi/mvm/rs.c b/drivers/net/wireless/iwlwifi/mvm/rs.c
[]
@@ -1868,7 +1865,8 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                /* Else poor success; go back to mode in "active" table */
                } else {
                        IWL_DEBUG_RATE(mvm,
-                                      "LQ: GOING BACK TO THE OLD TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
+                                      "GOING BACK TO THE OLD TABLE: SR %d "
+                                      "cur-tpt %d old-tpt %d\n",
                                       window->success_ratio,
                                       window->average_tpt,
                                       lq_sta->last_tpt);

Re: checkpatch not warning for some split strings

[Josh Triplett]

On Mon, Dec 02, 2013 at 01:23:58PM -0800, Joe Perches wrote:
> Hey Josh.
> 
> Back when you added commit ca56dc098ca
> ("checkpatch: check for quoted strings broken across lines")
> 
> You added this test case:
> 
>     Test case:
>     
>     void context(void)
>     {
>         struct { unsigned magic; const char *strdata; } foo[] = {
>                 { 42, "these strings"
>                       "do not produce warnings" },
>                 { 256, "though perhaps"
>                        "they should" },
>         };
> 
> which avoids emitting a warning on split strings across
> multiple lines without a function-call like '(' use on
> the line above.
> 
> Perhaps the "\(" test should be removed as checkpatch
> doesn't emit a warning for some uses like:
> 
> diff --git a/drivers/net/wireless/iwlwifi/mvm/rs.c b/drivers/net/wireless/iwlwifi/mvm/rs.c
> []
> @@ -1868,7 +1865,8 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
>                 /* Else poor success; go back to mode in "active" table */
>                 } else {
>                         IWL_DEBUG_RATE(mvm,
> -                                      "LQ: GOING BACK TO THE OLD TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
> +                                      "GOING BACK TO THE OLD TABLE: SR %d "
> +                                      "cur-tpt %d old-tpt %d\n",
>                                        window->success_ratio,
>                                        window->average_tpt,
>                                        lq_sta->last_tpt);

That one should definitely emit a warning.  However, removing the \(
test entirely will introduce warnings on many other strings embedded in
data structures; only drop that test if you've diffed the checkpatch
output for the kernel with and without it and you're comfortable with
the *huge* number of additional warnings it'll introduce.

- Josh Triplett

[PATCH] checkpatch: More comprehensive split strings warning

[Joe Perches]

The current checkpatch test for split strings does
not find several cases that should be found.

For instance:

diff --git a/drivers/net/wireless/iwlwifi/mvm/rs.c b/drivers/net/wireless/iwlwifi/mvm/rs.c
[]
@@ -1868,7 +1865,8 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
 		/* Else poor success; go back to mode in "active" table */
 		} else {
 			IWL_DEBUG_RATE(mvm,
-				       "LQ: GOING BACK TO THE OLD TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
+				       "GOING BACK TO THE OLD TABLE: SR %d "
+				       "cur-tpt %d old-tpt %d\n",
 				       window->success_ratio,
 				       window->average_tpt,
 				      lq_sta->last_tpt);

does not currently emit a warning.

Improve the test to find these cases.

Add more exceptions to reduce false positives for
assembly and octal/hex string constants.

Signed-off-by: Joe Perches <joe@perches.com>
---
 scripts/checkpatch.pl | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 38be5d5..1d0d5ac 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2049,16 +2049,12 @@ sub process {
 		}
 
 # Check for user-visible strings broken across lines, which breaks the ability
-# to grep for the string.  Limited to strings used as parameters (those
-# following an open parenthesis), which almost completely eliminates false
-# positives, as well as warning only once per parameter rather than once per
-# line of the string.  Make an exception when the previous string ends in a
-# newline (multiple lines in one string constant) or \n\t (common in inline
-# assembly to indent the instruction on the following line).
+# to grep for the string.  Make exceptions when the previous string ends in a
+# newline (multiple lines in one string constant) or '\t', '\r', ';', or '{'
+# (common in inline assembly) or is a octal \123 or hexadecimal \xaf value
 		if ($line =~ /^\+\s*"/ &&
 		    $prevline =~ /"\s*$/ &&
-		    $prevline =~ /\(/ &&
-		    $prevrawline !~ /\\n(?:\\t)*"\s*$/) {
+		    $prevrawline !~ /(?:\\(?:[ntr]|[0-7]{1,3}|x[0-9a-fA-F]{1,2})|;\s*|\{\s*)"\s*$/) {
 			WARN("SPLIT_STRING",
 			     "quoted string split across lines\n" . $hereprev);
 		}

Re: [PATCH] checkpatch: More comprehensive split strings warning

[Josh Triplett]

On Mon, Dec 02, 2013 at 09:44:17PM -0800, Joe Perches wrote:
> The current checkpatch test for split strings does
> not find several cases that should be found.
> 
> For instance:
> 
> diff --git a/drivers/net/wireless/iwlwifi/mvm/rs.c b/drivers/net/wireless/iwlwifi/mvm/rs.c
> []
> @@ -1868,7 +1865,8 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
>  		/* Else poor success; go back to mode in "active" table */
>  		} else {
>  			IWL_DEBUG_RATE(mvm,
> -				       "LQ: GOING BACK TO THE OLD TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
> +				       "GOING BACK TO THE OLD TABLE: SR %d "
> +				       "cur-tpt %d old-tpt %d\n",
>  				       window->success_ratio,
>  				       window->average_tpt,
>  				      lq_sta->last_tpt);
> 
> does not currently emit a warning.
> 
> Improve the test to find these cases.
> 
> Add more exceptions to reduce false positives for
> assembly and octal/hex string constants.

Nice choice of exceptions; that should work quite well.

> Signed-off-by: Joe Perches <joe@perches.com>

Reviewed-by: Josh Triplett <josh@joshtriplett.org>

>  scripts/checkpatch.pl | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 38be5d5..1d0d5ac 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2049,16 +2049,12 @@ sub process {
>  		}
>  
>  # Check for user-visible strings broken across lines, which breaks the ability
> -# to grep for the string.  Limited to strings used as parameters (those
> -# following an open parenthesis), which almost completely eliminates false
> -# positives, as well as warning only once per parameter rather than once per
> -# line of the string.  Make an exception when the previous string ends in a
> -# newline (multiple lines in one string constant) or \n\t (common in inline
> -# assembly to indent the instruction on the following line).
> +# to grep for the string.  Make exceptions when the previous string ends in a
> +# newline (multiple lines in one string constant) or '\t', '\r', ';', or '{'
> +# (common in inline assembly) or is a octal \123 or hexadecimal \xaf value
>  		if ($line =~ /^\+\s*"/ &&
>  		    $prevline =~ /"\s*$/ &&
> -		    $prevline =~ /\(/ &&
> -		    $prevrawline !~ /\\n(?:\\t)*"\s*$/) {
> +		    $prevrawline !~ /(?:\\(?:[ntr]|[0-7]{1,3}|x[0-9a-fA-F]{1,2})|;\s*|\{\s*)"\s*$/) {
>  			WARN("SPLIT_STRING",
>  			     "quoted string split across lines\n" . $hereprev);
>  		}
> 
>