Fix tools script python warnings

Change-Id: Ibdcd957ef689efd3ca0bd4ee729eb9f1e767413a

tools/ci/activate

@@ -6,3 +6,5 @@ function tools_dir {
 export CI_TOOLS_DIR=${CI_TOOLS_DIR:-$(tools_dir)}
 export CI_TOOLS_ORIGINAL_PATH=${CI_TOOLS_ORIGINAL_PATH:-${PATH}}
 export PATH=${CI_TOOLS_DIR}:${PATH}
+
+export PYTHONWARNINGS=${PYTHONWARNINGS:-ignore}

tools/ci/python

@@ -8,40 +8,49 @@ PYTHON_VERSION=${PYTHON_VERSION:-}
 function python() {
     # call get_python_exe only the first time it is required
     export PYTHON_EXECUTABLE=${PYTHON_EXECUTABLE:-$(python_executable)}
-    "${PYTHON_EXECUTABLE}" "$@"
+    if [ -x "${PYTHON_EXECUTABLE}" ]; then
+        "${PYTHON_EXECUTABLE}" "$@"
+    else
+        exit 1
+    fi
 }
 
 
 function python_executable() {
-    local version=${PYTHON_VERSION}
-
-    select_python_executables "${version}" \
-        $(list_python_executables "${version}") | head -1
+    local version=${PYTHON_VERSION:-}
+    local executables=( $( list_python_executables ) )
+    for executable in "${executables[@]}"; do
+        if "${executable}" -c "${SELECT_PYTHON_EXECUTABLE_SCRIPT}" "${version}"; then
+            echo "${executable}"
+            exit 0
+        fi
+    done
+    fail 1 "No such Python executable (PYTHON_VERSION=${PYTHON_VERSION})"
 }
 
 
 function list_python_executables() {
-    PATH=${CI_TOOLS_ORIGINAL_PATH} which $(list_python_names "${version}")
+    PATH=${CI_TOOLS_ORIGINAL_PATH} which $(list_python_names) 2> /dev/null
 }
 
 
 function list_python_names() {
-    local version=${1:-}
+    local version=${PYTHON_VERSION}
     if [ "${version}" != "" ]; then
         echo "python${version}"
     fi
+    echo python3.7
+    echo python3.6
     echo python3
     echo python
 }
 
 
-function select_python_executables() {
-    local version=${1:-}
-    local executable
+function fail() {
+    local error=$1
     shift
-    for executable in "$@"; do
-        "${executable}" -c "${SELECT_PYTHON_EXECUTABLE_SCRIPT}" "${version}"
-    done
+    echo "$@" 1>&2
+    exit "${error}"
 }
 
 
@@ -49,8 +58,13 @@ read -r -d '' SELECT_PYTHON_EXECUTABLE_SCRIPT << END_OF_SCRIPT
 import sys
 version = ".".join(str(i) for i in sys.version_info[:3])
 if version.startswith(sys.argv[1]):
-    print(sys.executable)
+    exit(0)
+else:
+    exit(1)
 END_OF_SCRIPT
 
 
-python "$@"
+if [ $(basename "$0") == python ]; then
+    set -euo pipefail
+    python "$@"
+fi

tools/ci/realpath

@@ -5,4 +5,5 @@ import sys
 
 args = sys.argv[1:] or ['.']
 results = [os.path.realpath(a) for a in args]
-print(' '.join(results))
+output = '\n'.join(results) + '\n'
+sys.stdout.write(output)