[PATCH v4] checkpatch: add fix option for LOGICAL_CONTINUATIONS

From: Aditya Srivastava <yashsri421@gmail.com>
To: joe@perches.com
Cc: yashsri421@gmail.com, lukas.bulwahn@gmail.com,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4] checkpatch: add fix option for LOGICAL_CONTINUATIONS
Date: Sun, 22 Nov 2020 02:34:42 +0530	[thread overview]
Message-ID: <20201121210442.17299-1-yashsri421@gmail.com> (raw)
In-Reply-To: <a6ee46ce01747627196478ff2a965d48dd4eed73.camel@perches.com>

Currently, checkpatch warns if logical continuations are placed at the
start of a line and not at the end of previous line.

E.g., running checkpatch on commit 3485507fc272 ("staging:
bcm2835-camera: Reduce length of enum names") reports:

CHECK:LOGICAL_CONTINUATIONS: Logical continuations should be on the
previous line
+	if (!ret
+	    && camera_port ==

Provide a simple fix by adding logical operator at the end of previous
line and removing from current line, if both the lines are additions
(ie start with '+')

Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
---
changes in v2: quote $operator at substitution

changes in v3: add a check for previous line ending with comment;
If so, insert $operator at the last non-comment, non-whitespace char of the previous line

changes in v4: improve the matching mechanism by matching line termination at comment or white space;
insert the operator before comments (if any) separated by a whitespace;
append the comment and its pre-whitespace after the inserted operator (if comment was present),
ie if no comment was present nothing will be inserted after the operator

 scripts/checkpatch.pl | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 5b1a5a65e69a..43a05519665d 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3553,8 +3553,19 @@ sub process {
 
 # check for && or || at the start of a line
 		if ($rawline =~ /^\+\s*(&&|\|\|)/) {
-			CHK("LOGICAL_CONTINUATIONS",
-			    "Logical continuations should be on the previous line\n" . $hereprev);
+			my $operator = $1;
+			if (CHK("LOGICAL_CONTINUATIONS",
+				"Logical continuations should be on the previous line\n" . $hereprev) &&
+			    $fix && $prevrawline =~ /^\+/) {
+				# add logical operator to the previous line, remove from current line
+				# match line termination at comment or whitespace
+				if ($prevrawline =~ /(\s*(?:\/\/.*)*)$/) {
+					my $match = $1;
+					$fixed[$fixlinenr - 1] =~ s/$match//;
+					$fixed[$fixlinenr - 1] .= " $operator$match";
+				}
+				$fixed[$fixlinenr] =~ s/\Q$operator\E\s*//;
+			}
 		}
 
 # check indentation starts on a tab stop
-- 
2.17.1

