Prevent "/usr/bin/env: 'python': No such file or directory" error. am: 078b9d3bbc am: f32100cdae am: 920b89c58a

Original change: https://android-review.googlesource.com/c/platform/prebuilts/asuite/+/1675588

Change-Id: I79db9d6d320d0f97f589857c3b5526be1ae75353

1 files changed, 46 insertions, 57 deletions

diff --git a/atest/linux-x86/atest b/atest/linux-x86/atest
index 6fa785b..92aef34 100755
--- a/atest/linux-x86/atest
+++ b/atest/linux-x86/atest
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env bash
 # Copyright 2020, The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -13,62 +13,51 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from __future__ import print_function
+ATEST_DIR=$(dirname $0)
+[ "$(uname -s)" == "Darwin" ] && { realpath(){ echo "$(cd $(dirname $1);pwd -P)/$(basename $1)"; }; }
 
-import os
-import subprocess
+function get_python_version() {
+    python - << END
 import sys
+print(sys.version_info.major)
+END
+}
 
-# Version and disclaimers.
-MIN_PY3_VERSION = (3, 5)
-PYTHON = 'python3'
-HELPER = ('Please install python {}+ for'
-          ' running the latest atest.').format(MIN_PY3_VERSION)
-FALLBACK_MSG = ('[Warning] You are running a FALLBACK version of atest!'
-                '\nThis fallback version of atest will be NO LONGER MAINTAINED/BUG FIXING!'
-                '\n{}').format(HELPER)
-DISCLAIMER_MSG = '[Warning] Outdated version of python3 detected!\n{}'.format(HELPER)
-ATEST_DIR = os.path.dirname(os.path.realpath(__file__))
-ATEST = os.path.join(ATEST_DIR, 'atest-py3')
-FALLBACK_ATEST = os.path.join(ATEST_DIR, 'atest-py2')
-
-
-def print_message(context, separator='#'):
-    """A printer function with separator.
-
-    Args:
-        context: A string of context to print.
-        separator: A string which will be used as separator char.
-    """
-    print('\n' + separator*72)
-    print(context)
-    print(separator*72 + '\n')
-
-
-def has_valid_python3(version):
-    proc = subprocess.Popen(
-          [PYTHON, '-c', 'import sys; '
-           'print(sys.version_info.major, sys.version_info.minor)'],
-          stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-    (output, _) = proc.communicate()
-    current_ver = tuple(int(x) for x in output.decode('utf-8').split())
-    return current_ver >= version
-
-
-def has_command(cmd):
-    paths = os.getenv('PATH', '').split(':')
-    for path in paths:
-        if os.path.isfile(os.path.join(path, cmd)):
-            return True
-    return False
-
-
-if __name__ == '__main__':
-    if not has_command(PYTHON):
-        print_message(FALLBACK_MSG)
-        os.execv(FALLBACK_ATEST, sys.argv)
-    else:
-        # Print warning if the installed python3 doesn't meet the requirement.
-        if not has_valid_python3(MIN_PY3_VERSION):
-            print_message(DISCLAIMER_MSG)
-        os.execv(ATEST, sys.argv)
+function is_python3() {
+    python3 - << END
+import sys
+current_version = (sys.version_info.major, sys.version_info.minor)
+if current_version >= (3, 4):
+    print(True)
+else:
+    print(False)
+END
+}
+
+# 1. Expect in most Linux that comes with python3.
+if which python3 >/dev/null 2>&1; then
+    if [[ x$(is_python3) == x"False" ]]; then
+        echo "[Warning] Outdated version of python3 detected!"
+        echo "Please install python 3.5+ to run the latest atest."
+    fi
+    ATEST="$(realpath $ATEST_DIR)/atest-py3"
+# 2. For legacy mechines that only have python2
+elif which python2 >/dev/null 2>&1; then
+    ATEST="$(realpath $ATEST_DIR)/atest-py2"
+    echo "[Warning] You are running a FALLBACK version of atest!"
+    echo "This fallback version of atest will be NO LONGER MAINTAINED/BUG FIXING!"
+# In some distros there are no explicit python2/python3 executables.
+elif which python >/dev/null 2>&1; then
+    if [[ "$(get_python_version)" -eq 3 ]]; then
+        echo "Please point $(which python) to /usr/bin/python3 to run atest."
+    else
+        echo "Please point $(which python) to /usr/bin/python2 to run atest."
+    fi
+    exit 0
+# Unlikely to happen, exit if no python/python2/python3 executables at all.
+else
+    echo "Please install python 3.5+ to run the latest atest."
+    exit 0
+fi
+
+$ATEST "$@"