fix: use print() function in both Python 2 and Python 3 (#18395)

Legacy print statements are syntax errors in Python 3 but print() function works as expected in both Python 2 and Python 3.

Old style exceptions are syntax errors in Python 3 but new style exceptions work as expected in both Python 2 and Python 3.

build/npm-run.py

@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+from __future__ import print_function
 import os
 import subprocess
 import sys
@@ -13,6 +14,6 @@
     ] + sys.argv[1:]
 try:
     subprocess.check_output(args, stderr=subprocess.STDOUT)
-except subprocess.CalledProcessError, e:
+except subprocess.CalledProcessError as e:
     print("NPM script '" + sys.argv[2] + "' failed with code '" + str(e.returncode) + "':\n" + e.output)
     sys.exit(e.returncode)

build/zip.py

@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+from __future__ import print_function
 import os
 import subprocess
 import sys
@@ -41,7 +42,7 @@ def execute(argv):
     output = subprocess.check_output(argv, stderr=subprocess.STDOUT)
     return output
   except subprocess.CalledProcessError as e:
-    print e.output
+    print(e.output)
     raise e
 
 def main(argv):

script/check-relative-doc-links.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 
+from __future__ import print_function
 import os
 import sys
 import re
@@ -99,9 +100,9 @@ def checkSections(sections, lines):
 
 def print_errors(filepath, brokenLink):
   if brokenLink:
-    print "File Location: " + filepath
+    print("File Location: " + filepath)
     for link in brokenLink:
-      print "\tBroken links: " + link
+      print("\tBroken links: " + link)
 
 
 if __name__ == '__main__':

script/check-trailing-whitespace.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 
+from __future__ import print_function
 import argparse
 import os
 import sys
@@ -48,7 +49,7 @@ def hasTrailingWhiteSpace(filepath, fix):
   for line in lines:
     fixed_lines.append(line.rstrip() + '\n')
     if not fix and line != line.rstrip():
-      print "Trailing whitespace in: " + filepath
+      print("Trailing whitespace in: " + filepath)
       return True
   if fix:
     with open(filepath, 'w') as f:

script/get-version.py

@@ -1,11 +1,12 @@
 #!/usr/bin/env python
 
+from __future__ import print_function
 import sys
 
 from lib.util import get_electron_version
 
 def main():
-  print get_electron_version()
+  print(get_electron_version())
 
 if __name__ == '__main__':
   sys.exit(main())

script/lib/config.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 
+from __future__ import print_function
 import errno
 import os
 import platform
@@ -47,7 +48,8 @@ def get_env_var(name):
     # TODO Remove ATOM_SHELL_* fallback values
     value = os.environ.get('ATOM_SHELL_' + name, '')
     if value:
-      print 'Warning: Use $ELECTRON_' + name + ' instead of $ATOM_SHELL_' + name
+      print('Warning: Use $ELECTRON_' + name +
+            ' instead of $ATOM_SHELL_' + name)
   return value
 
 
@@ -63,7 +65,7 @@ def s3_config():
 
 
 def enable_verbose_mode():
-  print 'Running in verbose mode'
+  print('Running in verbose mode')
   global verbose_mode
   verbose_mode = True
 

script/lib/native_tests.py

@@ -11,6 +11,11 @@
 sys.path.append(PYYAML_LIB_DIR)
 import yaml  #pylint: disable=wrong-import-position,wrong-import-order
 
+try:
+  basestring        # Python 2
+except NameError:   # Python 3
+  basestring = str  # pylint: disable=redefined-builtin
+
 
 class Verbosity:
   CHATTY = 'chatty'  # stdout and stderr

script/lib/util.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 
+from __future__ import print_function
 import atexit
 import contextlib
 import datetime
@@ -64,7 +65,7 @@ def download(text, url, path):
     if hasattr(ssl, '_create_unverified_context'):
       ssl._create_default_https_context = ssl._create_unverified_context
 
-    print "Downloading %s to %s" % (url, path)
+    print("Downloading %s to %s" % (url, path))
     web_file = urllib2.urlopen(url)
     file_size = int(web_file.info().getheaders("Content-Length")[0])
     downloaded_size = 0
@@ -83,12 +84,12 @@ def download(text, url, path):
       if not ci:
         percent = downloaded_size * 100. / file_size
         status = "\r%s  %10d  [%3.1f%%]" % (text, downloaded_size, percent)
-        print status,
+        print(status, end=' ')
 
     if ci:
-      print "%s done." % (text)
+      print("%s done." % (text))
     else:
-      print
+      print()
   return path
 
 
@@ -148,27 +149,27 @@ def execute(argv, env=None, cwd=None):
   if env is None:
     env = os.environ
   if is_verbose_mode():
-    print ' '.join(argv)
+    print(' '.join(argv))
   try:
     output = subprocess.check_output(argv, stderr=subprocess.STDOUT,
                                      env=env, cwd=cwd)
     if is_verbose_mode():
-      print output
+      print(output)
     return output
   except subprocess.CalledProcessError as e:
-    print e.output
+    print(e.output)
     raise e
 
 
 def execute_stdout(argv, env=None, cwd=None):
   if env is None:
     env = os.environ
   if is_verbose_mode():
-    print ' '.join(argv)
+    print(' '.join(argv))
     try:
       subprocess.check_call(argv, env=env, cwd=cwd)
     except subprocess.CalledProcessError as e:
-      print e.output
+      print(e.output)
       raise e
   else:
     execute(argv, env, cwd)