Add tox checker for lengths of new lines only

- Still non-voting, but useful.

Change-Id: Idd6f345f0f14fdbc237ff66f5e010801ea08dc5b
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

3 files changed, 67 insertions, 12 deletions

diff --git a/resources/libraries/bash/entry/check/line.sh b/resources/libraries/bash/entry/check/line.sh
index c58c7d0126..932f3cdbe9 100644
--- a/resources/libraries/bash/entry/check/line.sh
+++ b/resources/libraries/bash/entry/check/line.sh
@@ -30,10 +30,11 @@ source "${BASH_FUNCTION_DIR}/common.sh" || {
     exit 1
 }
 
-# docs contains too many wide formatted tables.
+# Directory docs contains too many wide formatted tables.
 # .txt contains lines with wide URLs.
 piped_command='set -exuo pipefail && grep -rn ".\{81\}" "resources/" "tests/"'
 piped_command+=' | fgrep -v .svg | fgrep -v .txt | tee "lines.log" | wc -l'
+# TODO: The greps "fail" if no long line remains. Fix that if it ever happens.
 lines="$(bash -c "${piped_command}")" || die
 if [ "${lines}" != "0" ]; then
     # TODO: Decide which text goes to stdout and which to stderr.
diff --git a/resources/libraries/bash/entry/check/new_line.sh b/resources/libraries/bash/entry/check/new_line.sh
new file mode 100644
index 0000000000..49c3d65815
--- /dev/null
+++ b/resources/libraries/bash/entry/check/new_line.sh
@@ -0,0 +1,51 @@
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -exuo pipefail
+
+# This file should be executed from tox, as the assumend working directory
+# is different from where this file is located.
+# This file does not have executable flag nor shebang,
+# to dissuade non-tox callers.
+
+# This script runs a grep-based command and fails if it detects any lines
+# edited or added since HEAD~ and longer than 80 characters.
+# The grep output stored to new_lines.log (overwriting).
+
+# See lines.log to locate where the lines are.
+
+# "set -eu" handles failures from the following two lines.
+BASH_CHECKS_DIR="$(dirname $(readlink -e "${BASH_SOURCE[0]}"))"
+BASH_FUNCTION_DIR="$(readlink -e "${BASH_CHECKS_DIR}/../../function")"
+source "${BASH_FUNCTION_DIR}/common.sh" || {
+    echo "Source failed." >&2
+    exit 1
+}
+
+# Greps do "fail" on zero line output, we need to ignore that in the final grep.
+piped_command="set -exuo pipefail && git diff -U0 HEAD~ | grep '^\+' | "
+piped_command+="cut -c2- | grep -v '^\+\+ ' | { grep '.\{81\}' || true; } | "
+piped_command+="tee 'new_lines.log' | wc -l"
+lines="$(bash -c "${piped_command}")" || die
+if [ "${lines}" != "0" ]; then
+    # TODO: Decide which text goes to stdout and which to stderr.
+    warn "Long lines detected: ${lines}"
+    # TODO: Disable when output size does more harm than good.
+    cat "new_lines.log" >&2
+    warn
+    warn "New line length checker: FAIL"
+    exit 1
+fi
+
+warn
+warn "New line length checker: PASS"
diff --git a/tox.ini b/tox.ini
index 0fd8645328..6413c95307 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,12 +25,13 @@
 # will execute only checks defined in "pylint" tox environment.
 
 [tox]
-envlist = linelength, autogen, pylint
+envlist = new_line_length, line_length, autogen, pylint
 # The following is needed as tox requires setup.py by default.
 skipsdist = true
+# Just a shorthand to avoid long lines.
+checker_dir = ./resources/libraries/bash/entry/check
 
-# TODO: Tox prints various warnings.
-#   Figure out what they are about and fix them.
+# TODO: Tox prints various warnings. Figure them out and fix them.
 
 [testenv:pylint]
 deps =
@@ -39,24 +40,26 @@ deps =
 whitelist_externals = /bin/bash
 setenv = PYTHONPATH = {toxinidir}
 # Run pylint, but hide its return value until python warnings are cleared.
-commands = bash -c "bash resources/libraries/bash/entry/check/pylint.sh || true"
+commands = bash -c "bash {[tox]checker_dir}/pylint.sh || true"
 
 # TODO: See FIXME in https://gerrit.fd.io/r/16423
 
-[testenv:linelength]
+[testenv:line_length]
 whitelist_externals = /bin/bash
 # Fix all transgressions and remove the " || true" workaround.
-commands = bash -c "bash resources/libraries/bash/entry/check/line.sh || true"
+commands = bash -c "bash {[tox]checker_dir}/line.sh || true"
 
-# It would be possible to add a check which fails
-# if number of long lines increases (from parent commit value),
-# and have it voting.
-# But that would basically prevent us from adding new suites righ now. :(
+[testenv:new_line_length]
+whitelist_externals = /bin/bash
+# Adding .svg, big .rst tables, .yaml and similar still requires long lines.
+# As current implementation is too dumb to filter those out,
+# the checker has to remain non-voting.
+commands = bash -c "bash {[tox]checker_dir}/new_line.sh || true"
 
 [testenv:autogen]
 whitelist_externals = /bin/bash
 setenv = PYTHONPATH = {toxinidir}
-commands = bash resources/libraries/bash/entry/check/autogen.sh
+commands = bash {[tox]checker_dir}/autogen.sh
 
 # TODO: Migrate current docs check here.
 # TODO: Create license checker.