presubmit: add check for newlines in CPRINTS strings

There should be no newlines in string parameters of the CPRINTS()
macro, it adds a newline unconditionally.

BRANCH=none
BUG=none
TEST=created a failing patch and observed expected error message:

.  $ ./util/presubmit_check.sh
.  +++ b/chip/g/usb-stream.c
.  +	CPRINTS("this is a bad, bad, string\n", yes);
.  error: CPRINTS strings should not include newline characters

Change-Id: I9b6338743d2493aa731dd49ae35f9de043fd860b
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1665449
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/util/presubmit_check.sh b/util/presubmit_check.sh
index 822633f0f8..ed1cbe6071 100755
--- a/util/presubmit_check.sh
+++ b/util/presubmit_check.sh
@@ -4,6 +4,23 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# Verify there is no CPRINTS("....\n", ...) statements added to the code.
+upstream_branch="$(git rev-parse --abbrev-ref --symbolic-full-name @{u} \
+    2>/dev/null)"
+if [[ -z ${upstream_branch} ]]; then
+  echo "Current branch does not have an upstream branch" >&2
+  exit 1
+fi
+# This will print the offending CPRINTS invocations, if any, and the names of
+# the files they are in.
+if git diff "${upstream_branch}" HEAD | grep -e '^+\(.*CPRINTS(.*\\n"\|++\)' |
+    grep CPRINTS -B1 >&2 ; then
+  echo "error: CPRINTS strings should not include newline characters" >&2
+  exit 1
+fi
+
+# Verify that all targets were built and all tests passed after the latest
+# source code modification.
 if [[ ! -e .tests-passed ]]; then
   echo 'Unit tests have not passed. Please run "make buildall -j".'
   exit 1