Exit trap cleanup in docstheme-build-translated.sh

Add a catch-all `cleanup` exit trap to docstheme-build-translated.sh.
The script creates interim artifacts in doc/source (which it arguably
shouldn't do) like .pot files and .rst sources modified with index
headers pointing to translations. Previously, if the doc build failed,
these artifacts would be left behind, creating a mess for a developer
attempting to make and commit doc changes locally. This patch
accumulates the existing cleanups into an exit trap so they happen
whether the script succeeds or fails.

Developers of openstackdocstheme itself may disable this cleanup trap by
setting the DOCSTHEME_BUILD_TRANSLATED__NO_CLEANUP environment variable
to a nonempty value.

Change-Id: If48c5705c34f940e78e3a34e602e48496a397629

bin/docstheme-build-translated.sh

@@ -45,7 +45,6 @@ function prepare_language_index {
     # Global variables
     HAS_LANG=0
     LANG_INDEX=`mktemp`
-    trap "rm -f -- $LANG_INDEX" EXIT
 
     cat <<EOF >> $LANG_INDEX
 [
@@ -113,10 +112,27 @@ function add_language_index_to_original {
 
 function recover_rst_files {
     for f in `find $DIRECTORY/source -name '*.rst'`; do
-        mv $f.backup $f
+        [ -f $f.backup ] && mv $f.backup $f
     done
 }
 
+function remove_pot_files {
+    # remove newly created pot files
+    rm -f ${DIRECTORY}/source/locale/*.pot
+}
+
+function cleanup {
+    if [ $DOCSTHEME_BUILD_TRANSLATED__NO_CLEANUP ]; then
+        echo "Skipping cleanup. Your repository is dirty."
+        return
+    fi
+    [ $LANG_INDEX ] && rm -f -- $LANG_INDEX
+    recover_rst_files
+    remove_pot_files
+}
+
+trap cleanup EXIT
+
 sphinx-build -a -W -b gettext \
     -d ${DIRECTORY}/build/doctrees.gettext \
     ${DIRECTORY}/source ${DIRECTORY}/source/locale/
@@ -201,8 +217,7 @@ for locale in `find ${DIRECTORY}/source/locale/ -maxdepth 1 -type d` ; do
     git checkout -q -- ${DIRECTORY}/source/locale/${language}/LC_MESSAGES/${DOCNAME}.po
 done
 
-# remove newly created pot files
-rm -f ${DIRECTORY}/source/locale/*.pot
+remove_pot_files
 
 add_language_index_to_original
 
@@ -210,5 +225,3 @@ add_language_index_to_original
 sphinx-build -a ${SPHINX_BUILD_OPTION_ENG} -b html \
     -d ${DIRECTORY}/build/doctrees \
     ${DIRECTORY}/source ${DIRECTORY}/build/html/
-
-recover_rst_files