Provide a quick way to run flake8

"run_tests.sh -p" always checks every file for errors even though you
have probably only changed a handful. This patch adds "run_tests.sh -8"
which only checks the files that were modified in the HEAD commit or
the current working tree.

It is borrowed from the recent nova commit b011325cc6.
The related ML post is:
http://lists.openstack.org/pipermail/openstack-dev/2014-August/043346.html

Change-Id: If3c8e5e3e442257f796374edba02c3a23a85839e

1 files changed, 30 insertions, 2 deletions

diff --git a/run_tests.sh b/run_tests.sh
index 85fc11085..001bcf459 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -25,6 +25,9 @@ function usage {
   echo "  --makemessages           Create/Update English translation files."
   echo "  --compilemessages        Compile all translation files."
   echo "  -p, --pep8               Just run pep8"
+  echo "  -8, --pep8-changed [<basecommit>]"
+  echo "                           Just run PEP8 and HACKING compliance check"
+  echo "                           on files changed since HEAD~1 (or <basecommit>)"
   echo "  -P, --no-pep8            Don't run pep8 by default"
   echo "  -t, --tabs               Check for tab characters in files."
   echo "  -y, --pylint             Just run pylint"
@@ -65,6 +68,7 @@ command_wrapper=""
 destroy=0
 force=0
 just_pep8=0
+just_pep8_changed=0
 no_pep8=0
 just_pylint=0
 just_docs=0
@@ -100,6 +104,7 @@ function process_option {
     -V|--virtual-env) always_venv=1; never_venv=0;;
     -N|--no-virtual-env) always_venv=0; never_venv=1;;
     -p|--pep8) just_pep8=1;;
+    -8|--pep8-changed) just_pep8_changed=1;;
     -P|--no-pep8) no_pep8=1;;
     -y|--pylint) just_pylint=1;;
     -j|--jshint) just_jshint=1;;
@@ -154,8 +159,7 @@ function run_jshint {
   jshint horizon/static/horizon/tests
 }
 
-function run_pep8 {
-  echo "Running flake8 ..."
+function warn_on_flake8_without_venv {
   set +o errexit
   ${command_wrapper} python -c "import hacking" 2>/dev/null
   no_hacking=$?
@@ -165,9 +169,28 @@ function run_pep8 {
       echo "OpenStack hacking is not installed on your host. Its detection will be missed." >&2
       echo "Please install or use virtual env if you need OpenStack hacking detection." >&2
   fi
+}
+
+function run_pep8 {
+  echo "Running flake8 ..."
+  warn_on_flake8_without_venv
   DJANGO_SETTINGS_MODULE=openstack_dashboard.test.settings ${command_wrapper} flake8
 }
 
+function run_pep8_changed {
+    # NOTE(gilliard) We want use flake8 to check the entirety of every file that has
+    # a change in it. Unfortunately the --filenames argument to flake8 only accepts
+    # file *names* and there are no files named (eg) "nova/compute/manager.py".  The
+    # --diff argument behaves surprisingly as well, because although you feed it a
+    # diff, it actually checks the file on disk anyway.
+    local base_commit=${testargs:-HEAD~1}
+    files=$(git diff --name-only $base_commit | tr '\n' ' ')
+    echo "Running flake8 on ${files}"
+    warn_on_flake8_without_venv
+    diff -u --from-file /dev/null ${files} | DJANGO_SETTINGS_MODULE=openstack_dashboard.test.settings ${command_wrapper} flake8 --diff
+    exit
+}
+
 function run_sphinx {
     echo "Building sphinx..."
     DJANGO_SETTINGS_MODULE=openstack_dashboard.test.settings ${command_wrapper} python setup.py build_sphinx
@@ -495,6 +518,11 @@ if [ $just_pep8 -eq 1 ]; then
     exit $?
 fi
 
+if [ $just_pep8_changed -eq 1 ]; then
+    run_pep8_changed
+    exit $?
+fi
+
 # Pylint
 if [ $just_pylint -eq 1 ]; then
     run_pylint