Re: [PATCH v2] checkpatch: add several Kconfig default value tests

[Joe Perches]

On Thu, 2019-07-04 at 17:40 +0800, Miles Chen wrote:
> This change adds 3 Kconfig default value tests:
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -3005,6 +3005,27 @@ sub process {
>  			     "Use of boolean is deprecated, please use bool instead.\n" . $herecurr);
>  		}
>  
> +# discourage redundant 'default n'
> +		if ($realfile =~ /Kconfig/ &&
> +		    $line =~ /^\+\s*default n$/) {
> +			WARN("DEFAULT_VALUE_STYLE",
> +			     "'default n' is the default value, no need to write it explicitly.\n" . $herecurr);
> +		}
> +
> +# discourage quote: use default [ynm], not default "[ynm]"
> +		if ($realfile =~ /Kconfig/ &&
> +		    $rawline =~ /^\+\s*default\s*"[ynm]"/) {
> +			WARN("DEFAULT_VALUE_STYLE",
> +			     "Use default [ynm] instead of default \"[ynm]\"\n" . $herecurr);
> +		}
> +
> +# discourage default \!?EXPERT
> +		if ($realfile =~ /Kconfig/ &&
> +		    $line =~ /^\+\s*default \!?EXPERT/) {
> +			WARN("DEFAULT_VALUE_STYLE",
> +			     "Avoid default turn on kernel configs by default !?EXPERT\n" . $herecurr);
> +		}
> +

I'd prefer to create a block for all the Kconfig file tests and
avoid multiply determining if the filename includes Kconfig so
the script runs a bit faster.

Also some trivial changes to the added tests with added --fix
capability.  Something like:
---
 scripts/checkpatch.pl | 139 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 85 insertions(+), 54 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 6cb99ec62000..4780149a8d30 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2934,60 +2934,98 @@ sub process {
 				      "Do not include the paragraph about writing to the Free Software Foundation's mailing address from the sample GPL notice. The FSF has changed addresses in the past, and may do so again. Linux already includes a copy of the GPL.\n" . $herevet)
 		}
 
-# check for Kconfig help text having a real description
-# Only applies when adding the entry originally, after that we do not have
-# sufficient context to determine whether it is indeed long enough.
-		if ($realfile =~ /Kconfig/ &&
-		    # 'choice' is usually the last thing on the line (though
-		    # Kconfig supports named choices), so use a word boundary
-		    # (\b) rather than a whitespace character (\s)
-		    $line =~ /^\+\s*(?:config|menuconfig|choice)\b/) {
-			my $length = 0;
-			my $cnt = $realcnt;
-			my $ln = $linenr + 1;
-			my $f;
-			my $is_start = 0;
-			my $is_end = 0;
-			for (; $cnt > 0 && defined $lines[$ln - 1]; $ln++) {
-				$f = $lines[$ln - 1];
-				$cnt-- if ($lines[$ln - 1] !~ /^-/);
-				$is_end = $lines[$ln - 1] =~ /^\+/;
-
-				next if ($f =~ /^-/);
-				last if (!$file && $f =~ /^\@\@/);
-
-				if ($lines[$ln - 1] =~ /^\+\s*(?:bool|tristate|prompt)\s*["']/) {
-					$is_start = 1;
-				} elsif ($lines[$ln - 1] =~ /^\+\s*(?:help|---help---)\s*$/) {
-					if ($lines[$ln - 1] =~ "---help---") {
-						WARN("CONFIG_DESCRIPTION",
-						     "prefer 'help' over '---help---' for new help texts\n" . $herecurr);
+# Kconfig tests
+		if ($realfile =~ /Kconfig/) {
+			# check for Kconfig help text having a real description
+			# Only applies when adding the entry originally, after
+			# that we do not have sufficient context to determine
+			# whether it is indeed long enough.
+			# 'choice' is usually the last thing on the line (though
+			# Kconfig supports named choices), so use a word
+			# boundary (\b) rather than a whitespace character (\s)
+			if ($line =~ /^\+\s*(?:config|menuconfig|choice)\b/) {
+				my $length = 0;
+				my $cnt = $realcnt;
+				my $ln = $linenr + 1;
+				my $f;
+				my $is_start = 0;
+				my $is_end = 0;
+				for (; $cnt > 0 && defined $lines[$ln - 1]; $ln++) {
+					$f = $lines[$ln - 1];
+					$cnt-- if ($lines[$ln - 1] !~ /^-/);
+					$is_end = $lines[$ln - 1] =~ /^\+/;
+
+					next if ($f =~ /^-/);
+					last if (!$file && $f =~ /^\@\@/);
+
+					if ($lines[$ln - 1] =~ /^\+\s*(?:bool|tristate|prompt)\s*["']/) {
+						$is_start = 1;
+					} elsif ($lines[$ln - 1] =~ /^\+\s*(?:help|---help---)\s*$/) {
+						if ($lines[$ln - 1] =~ "---help---") {
+							WARN("CONFIG_DESCRIPTION",
+							     "prefer 'help' over '---help---' for new help texts\n" . $herecurr);
+						}
+						$length = -1;
+					}
+
+					$f =~ s/^.//;
+					$f =~ s/#.*//;
+					$f =~ s/^\s+//;
+					next if ($f =~ /^$/);
+
+					# This only checks context lines in the patch
+					# and so hopefully shouldn't trigger false
+					# positives, even though some of these are
+					# common words in help texts
+					if ($f =~ /^\s*(?:config|menuconfig|choice|endchoice|
+							   if|endif|menu|endmenu|source)\b/x) {
+						$is_end = 1;
+						last;
 					}
-					$length = -1;
+					$length++;
+				}
+				if ($is_start && $is_end && $length < $min_conf_desc_length) {
+					WARN("CONFIG_DESCRIPTION",
+					     "please write a paragraph that describes the config symbol fully\n" . $herecurr);
 				}
+				#print "is_start<$is_start> is_end<$is_end> length<$length>\n";
+			}
 
-				$f =~ s/^.//;
-				$f =~ s/#.*//;
-				$f =~ s/^\s+//;
-				next if ($f =~ /^$/);
-
-				# This only checks context lines in the patch
-				# and so hopefully shouldn't trigger false
-				# positives, even though some of these are
-				# common words in help texts
-				if ($f =~ /^\s*(?:config|menuconfig|choice|endchoice|
-						  if|endif|menu|endmenu|source)\b/x) {
-					$is_end = 1;
-					last;
+# discourage the use of boolean for type definition attributes
+			if ($line =~ /^\+\s*\bboolean\b/) {
+				if (WARN("CONFIG_TYPE_BOOLEAN",
+					 "Use of boolean is deprecated, please use bool instead\n" . $herecurr) &&
+				    $fix) {
+					$fixed[$fixlinenr] =~ s/\bboolean\b/bool/;
+				}
+			}
+
+# Kconfig: discourage redundant 'default n'
+			if ($line =~ /^\+\s*default\s+n$/) {
+				if (WARN("CONFIG_DEFAULT_VALUE_STYLE",
+					 "'default n' is the default value, no need to write it explicitly\n" . $herecurr) &&
+				    $fix) {
+					fix_delete_line($fixlinenr, $rawline);
 				}
-				$length++;
 			}
-			if ($is_start && $is_end && $length < $min_conf_desc_length) {
-				WARN("CONFIG_DESCRIPTION",
-				     "please write a paragraph that describes the config symbol fully\n" . $herecurr);
+
+# Kconfig: discourage quoted defaults: use default [ynm], not default "[ynm]"
+			if ($rawline =~ /^\+\s*default\s+"([ynm])"/) {
+				if (WARN("CONFIG_DEFAULT_VALUE_STYLE",
+					 "Use 'default $1' not 'default \"$1\"'\n" . $herecurr) &&
+				    $fix) {
+					$fixed[$fixlinenr] =~ s/\b(default\s+)"(.)"/$1$2/;
+				}
+			}
+
+# Kconfig: discourage using default EXPERT or !EXPERT
+			if ($line =~ /^\+\s*default\s+\!?\s*EXPERT\b/) {
+				WARN("CONFIG_DEFAULT_VALUE_STYLE",
+				     "Avoid using default EXPERT\n" . $herecurr);
 			}
-			#print "is_start<$is_start> is_end<$is_end> length<$length>\n";
 		}
+# End of Kconfig tests
+
 
 # check for MAINTAINERS entries that don't have the right form
 		if ($realfile =~ /^MAINTAINERS$/ &&
@@ -3000,13 +3038,6 @@ sub process {
 			}
 		}
 
-# discourage the use of boolean for type definition attributes of Kconfig options
-		if ($realfile =~ /Kconfig/ &&
-		    $line =~ /^\+\s*\bboolean\b/) {
-			WARN("CONFIG_TYPE_BOOLEAN",
-			     "Use of boolean is deprecated, please use bool instead.\n" . $herecurr);
-		}
-
 		if (($realfile =~ /Makefile.*/ || $realfile =~ /Kbuild.*/) &&
 		    ($line =~ /\+(EXTRA_[A-Z]+FLAGS).*/)) {
 			my $flag = $1;