Useful pylint fixes

After combing through all the stuff pylint has found, this seems to me
the useful part.

The only questionable thing here, I think, could be the stuff related to
`open()` and explicit encoding argument. This changes behaviour!
Without specifying, the encoding is platform dependent. See
https://docs.python.org/3/library/functions.html#open for details.

Fixes ycm-core#1672

.ycm_extra_conf.py

@@ -29,9 +29,7 @@
 # For more information, please refer to <http://unlicense.org/>
 
 from sysconfig import get_path
-import platform
 import os.path as p
-import subprocess
 
 DIR_OF_THIS_SCRIPT = p.abspath( p.dirname( __file__ ) )
 DIR_OF_THIRD_PARTY = p.join( DIR_OF_THIS_SCRIPT, 'third_party' )
@@ -120,7 +118,7 @@ def FindCorrespondingSourceFile( filename ):
 def PathToPythonUsedDuringBuild():
   try:
     filepath = p.join( DIR_OF_THIS_SCRIPT, 'PYTHON_USED_DURING_BUILDING' )
-    with open( filepath ) as f:
+    with open( filepath, encoding = 'utf8' ) as f:
       return f.read().strip()
   except OSError:
     return None

build.py

@@ -130,7 +130,7 @@ def FindLatestMSVC( quiet ):
     ).strip().decode()
     if '.' in latest_full_v:
       try:
-        latest_v = int( latest_full_v.split( '.' )[ 0 ] )
+        latest_v = int( latest_full_v.split( '.', 1 )[ 0 ] )
       except ValueError:
         raise ValueError( f"{ latest_full_v } is not a version number." )
 
@@ -464,10 +464,10 @@ def ParseArguments():
                                DEFAULT_RUST_TOOLCHAIN + '" is tested/'
                               'supported by the maintainers of YCM/ycmd' )
   parser.add_argument( '--java-completer', action = 'store_true',
-                       help = 'Enable Java semantic completion engine.' ),
+                       help = 'Enable Java semantic completion engine.' )
   parser.add_argument( '--ts-completer', action = 'store_true',
                        help = 'Enable JavaScript and TypeScript semantic '
-                              'completion engine.' ),
+                              'completion engine.' )
   parser.add_argument( '--system-libclang', action = 'store_true',
                        help = 'Use system libclang instead of downloading one '
                        'from llvm.org. NOT RECOMMENDED OR SUPPORTED!' )
@@ -834,7 +834,6 @@ def CleanCsCompleter( build_dir, version ):
     if os.path.isfile( file_path ):
       os.remove( file_path )
     elif os.path.isdir( file_path ):
-      import shutil
       shutil.rmtree( file_path )
 
 
@@ -953,14 +952,14 @@ def EnableGoCompleter( args ):
 
 def WriteToolchainVersion( version ):
   path = p.join( RUST_ANALYZER_DIR, 'TOOLCHAIN_VERSION' )
-  with open( path, 'w' ) as f:
+  with open( path, 'w', encoding = 'utf8' ) as f:
     f.write( version )
 
 
 def ReadToolchainVersion():
   try:
     filepath = p.join( RUST_ANALYZER_DIR, 'TOOLCHAIN_VERSION' )
-    with open( filepath ) as f:
+    with open( filepath, encoding = 'utf8' ) as f:
       return f.read().strip()
   except OSError:
     return None
@@ -1234,7 +1233,7 @@ def Print( msg ):
 
 def WritePythonUsedDuringBuild():
   path = p.join( DIR_OF_THIS_SCRIPT, 'PYTHON_USED_DURING_BUILDING' )
-  with open( path, 'w' ) as f:
+  with open( path, 'w', encoding = 'utf8' ) as f:
     f.write( sys.executable )
 
 

run_tests.py

@@ -195,9 +195,9 @@ def BuildYcmdLibs( args ):
       '--core-tests'
     ]
 
-    for key in COMPLETERS:
+    for key, value in COMPLETERS.items():
       if key in args.completers:
-        build_cmd.extend( COMPLETERS[ key ][ 'build' ] )
+        build_cmd.extend( value[ 'build' ] )
 
     if args.msvc and platform.system() == 'Windows':
       build_cmd.extend( [ '--msvc', str( args.msvc ) ] )

update_clang_headers.py

@@ -39,7 +39,7 @@ def ExtractTar( uncompressed_data, destination ):
     tar_file.extractall( destination )
 
   # Determine the directory name
-  return os.path.join( destination, a_member.name.split( '/' )[ 0 ] )
+  return os.path.join( destination, a_member.name.split( '/', 1 )[ 0 ] )
 
 
 def ExtractLZMA( compressed_data, destination ):

update_unicode.py

@@ -580,7 +580,7 @@ def GenerateNormalizationTestCases( output_file ):
         JoinUnicodeToUtf8( captures[ 4 ].split() ) + '"},\n' )
 
   res[ -1 ] = res[ -1 ].rstrip( ',\n' )
-  with open( output_file, 'w' ) as f:
+  with open( output_file, 'w', encoding = 'utf8' ) as f:
     f.writelines( res )
 
 
@@ -602,7 +602,7 @@ def GenerateGraphemeBreakTestCases( output_file ):
                   for x in split_data ] ).rstrip( ',' ) + '}},\n' )
 
   res[ -1 ] = res[ -1 ].rstrip( ',\n' )
-  with open( output_file, 'w' ) as f:
+  with open( output_file, 'w', encoding = 'utf8' ) as f:
     f.writelines( res )
 
 

ycmd/__main__.py

@@ -142,7 +142,7 @@ def ParseArguments():
 def SetupLogging( log_level ):
   numeric_level = getattr( logging, log_level.upper(), None )
   if not isinstance( numeric_level, int ):
-    raise ValueError( 'Invalid log level: %s' % log_level )
+    raise ValueError( f'Invalid log level: { log_level }' )
 
   # Has to be called before any call to logging.getLogger()
   logging.basicConfig( format = '%(asctime)s - %(levelname)s - %(message)s',

ycmd/completers/cpp/clang_completer.py

@@ -436,9 +436,9 @@ def DebugInfo( self, request_data ):
 
     database_item = responses.DebugInfoItem(
       key = 'compilation database path',
-      value = '{0}'.format( database_directory ) )
+      value = f'{ database_directory }' )
     flags_item = responses.DebugInfoItem(
-      key = 'flags', value = '{0}'.format( list( flags ) ) )
+      key = 'flags', value = f'{ list( flags ) }' )
     filename_item = responses.DebugInfoItem(
       key = 'translation unit', value = filename )
 

ycmd/completers/cpp/flags.py

@@ -673,13 +673,12 @@ def UserIncludePaths( user_flags, filename ):
       it = iter( user_flags )
       for user_flag in it:
         user_flag_len = len( user_flag )
-        for flag in include_flags:
+        for flag, container in include_flags.items():
           if user_flag.startswith( flag ):
             flag_len = len( flag )
             include_path = ( next( it ) if user_flag_len == flag_len else
                              user_flag[ flag_len: ] )
             if include_path:
-              container = include_flags[ flag ]
               container.append( ToUnicode( include_path ) )
             break
     except StopIteration:

ycmd/completers/cs/cs_completer.py

@@ -387,7 +387,7 @@ def _GetSolutionFile( self, filepath ):
     return self._solution_for_file[ filepath ]
 
 
-class CsharpSolutionCompleter( object ):
+class CsharpSolutionCompleter:
   def __init__( self,
                 solution_path,
                 keep_logfiles,

ycmd/completers/language_server/generic_lsp_completer.py

@@ -48,11 +48,11 @@ def __init__( self, user_options, server_settings ):
       cmd = utils.FindExecutable( self._command_line[ 0 ] )
 
       if cmd is None:
-        utils.LOGGER.warn( "Unable to find any executable with the path %s. "
-                           "Cannot use %s completer.",
-                           self._command_line[ 0 ],
-                           self._name )
-        raise RuntimeError( f"Invalid cmdline: { str( self._command_line ) }" )
+        utils.LOGGER.warning( "Unable to find any executable with the path %s. "
+                              "Cannot use %s completer.",
+                              self._command_line[ 0 ],
+                              self._name )
+        raise RuntimeError( f"Invalid cmdline: { self._command_line }" )
 
       self._command_line[ 0 ] = cmd
       for idx in range( len( self._command_line ) ):

ycmd/completers/language_server/language_server_completer.py

@@ -564,8 +564,8 @@ def _ReadHeaders( self, data ):
               key, value = utils.ToUnicode( line ).split( ':', 1 )
               headers[ key.strip() ] = value.strip()
             except Exception:
-              LOGGER.exception( 'Received invalid protocol data from server: '
-                                 + str( line ) )
+              LOGGER.exception(
+                'Received invalid protocol data from server: %s', line )
               raise
 
         read_bytes += 1
@@ -1096,7 +1096,7 @@ def _StartServerNoLock( self, request_data ):
         self._project_directory,
         lambda globs: WatchdogHandler( self, globs ),
         self._port,
-        lambda request: self.WorkspaceConfigurationResponse( request ),
+        self.WorkspaceConfigurationResponse,
         self.GetDefaultNotificationHandler() )
     else:
       self._stderr_file = utils.CreateLogfile(
@@ -1116,7 +1116,7 @@ def _StartServerNoLock( self, request_data ):
           lambda globs: WatchdogHandler( self, globs ),
           self._server_handle.stdin,
           self._server_handle.stdout,
-          lambda request: self.WorkspaceConfigurationResponse( request ),
+          self.WorkspaceConfigurationResponse,
           self.GetDefaultNotificationHandler() )
       )
 
@@ -2865,7 +2865,7 @@ def ExecuteCommand( self, request_data, args ):
     if response is not None:
       return response
 
-    if len( edits ):
+    if edits:
       fixits = [ WorkspaceEditToFixIt(
         request_data,
         e[ 'edit' ],
@@ -3190,7 +3190,7 @@ def _SymbolInfoListToGoTo( request_data, symbols ):
   """Convert a list of LSP SymbolInformation into a YCM GoTo response"""
 
   def BuildGoToLocationFromSymbol( symbol ):
-    location, line_value = _LspLocationToLocationAndDescription(
+    location, _ = _LspLocationToLocationAndDescription(
       request_data,
       symbol[ 'location' ] )
 

ycmd/completers/python/python_completer.py

@@ -650,12 +650,3 @@ def _OffsetToPosition( start_end, filename, text, newlines ):
     if len( loc ) == 2:
       break
   return loc
-
-  # Invalid position - it's outside of the text. Just return the last
-  # position in the text. This is an internal error.
-  LOGGER.error( "Invalid offset %s in file %s with text %s and newlines %s",
-                offset,
-                filename,
-                text,
-                newlines )
-  raise RuntimeError( "Invalid file offset in diff" )

ycmd/completers/typescript/typescript_completer.py

@@ -265,7 +265,7 @@ def _ReaderLoop( self ):
         LOGGER.info( 'Received %s event from TSServer',  eventname )
         continue
       if msgtype != 'response':
-        LOGGER.error( 'Unsupported message type', msgtype )
+        LOGGER.error( 'Unsupported message type: %s', msgtype )
         continue
 
       seq = message[ 'request_seq' ]
@@ -373,9 +373,8 @@ def _Reload( self, request_data ):
 
     filename = request_data[ 'filepath' ]
     contents = request_data[ 'file_data' ][ filename ][ 'contents' ]
-    tmpfile = NamedTemporaryFile( delete = False )
-    tmpfile.write( utils.ToBytes( contents ) )
-    tmpfile.close()
+    with NamedTemporaryFile( delete = False ) as tmpfile:
+      tmpfile.write( utils.ToBytes( contents ) )
     self._SendRequest( 'reload', {
       'file':    filename,
       'tmpfile': tmpfile.name

ycmd/tests/clang/flags_test.py

@@ -99,7 +99,7 @@ def Settings( **kwargs ):
       assert_that( filename, equal_to( '/foo' ) )
 
 
-  def test_FlagsForFile_BadNonUnicodeFlagsAreAlsoRemoved( *args ):
+  def test_FlagsForFile_BadNonUnicodeFlagsAreAlsoRemoved( self, *args ):
     flags_object = flags.Flags()
 
     def Settings( **kwargs ):

ycmd/tests/clang/include_cache_test.py

@@ -102,7 +102,7 @@ def test_IncludeCache_Cached_NewMtime( self ):
       include_cache = IncludeCache()
       assert_that( include_cache._cache, equal_to( {} ) )
       foo_path = os.path.join( tmp_dir, 'foo' )
-      with open( foo_path, 'w' ) as foo_file:
+      with open( foo_path, 'w', encoding = 'utf8' ) as foo_file:
         foo_file.write( 'foo' )
 
       old_includes = include_cache.GetIncludes( tmp_dir )
@@ -124,7 +124,7 @@ def test_IncludeCache_Cached_NewMtime( self ):
       sleep( 2 )
 
       bar_path = os.path.join( tmp_dir, 'bar' )
-      with open( bar_path, 'w' ) as bar_file:
+      with open( bar_path, 'w', encoding = 'utf8' ) as bar_file:
         bar_file.write( 'bar' )
 
       new_includes = include_cache.GetIncludes( tmp_dir )

ycmd/tests/clangd/debug_info_test.py

@@ -336,7 +336,7 @@ def test_DebugInfo_ExtraConf_UseLocalOverDatabase( self, app ):
 
       with TemporaryClangProject( tmp_dir, database ):
         extra_conf = os.path.join( tmp_dir, '.ycm_extra_conf.py' )
-        with open( extra_conf, 'w' ) as f:
+        with open( extra_conf, 'w', encoding = 'utf8' ) as f:
           f.write( '''
 def Settings( **kwargs ):
   return { 'flags': [ '-x', 'c++', '-I', 'ycm' ] }

ycmd/tests/clangd/diagnostics_test.py

@@ -474,19 +474,19 @@ def test_Diagnostics_UpdatedOnBufferVisit( self, app ):
       source_contents = """#include "header.h"
 int main() {return S::h();}
 """
-      with open( source_file, 'w' ) as sf:
+      with open( source_file, 'w', encoding = 'utf8' ) as sf:
         sf.write( source_contents )
 
       header_file = os.path.join( tmp_dir, 'header.h' )
       old_header_content = """#pragma once
 struct S{static int h();};
 """
-      with open( header_file, 'w' ) as hf:
+      with open( header_file, 'w', encoding = 'utf8' ) as hf:
         hf.write( old_header_content )
 
       flags_file = os.path.join( tmp_dir, 'compile_flags.txt' )
       flags_content = """-xc++"""
-      with open( flags_file, 'w' ) as ff:
+      with open( flags_file, 'w', encoding = 'utf8' ) as ff:
         ff.write( flags_content )
 
       messages_request = { 'contents': source_contents,
@@ -502,7 +502,7 @@ def test_Diagnostics_UpdatedOnBufferVisit( self, app ):
       new_header_content = """#pragma once
   static int h();
   """
-      with open( header_file, 'w' ) as f:
+      with open( header_file, 'w', encoding = 'utf8' ) as f:
         f.write( new_header_content )
 
       # Send BufferSaved notification for the header
@@ -548,7 +548,7 @@ def test_Diagnostics_UpdatedOnBufferVisit( self, app ):
           break
 
       # Restore original content
-      with open( header_file, 'w' ) as f:
+      with open( header_file, 'w', encoding = 'utf8' ) as f:
         f.write( old_header_content )
 
       # Send BufferSaved notification for the header
@@ -571,5 +571,5 @@ def test_Diagnostics_UpdatedOnBufferVisit( self, app ):
           break
 
       # Assert no dirty files
-      with open( header_file, 'r' ) as f:
+      with open( header_file, 'r', encoding = 'utf8' ) as f:
         assert_that( f.read(), equal_to( old_header_content ) )

ycmd/tests/clangd/utilities_test.py

@@ -104,7 +104,7 @@ def test_ClangdCompleter_GetClangdCommand_CustomBinary( self ):
                           ( 13, 0, 0 ),
                           ( 13, 10, 10 ),
                           ( 100, 100, 100 ) ] )
-  def test_ClangdCompleter_CheckClangdVersion( *args ):
+  def test_ClangdCompleter_CheckClangdVersion( self, *args ):
     assert_that( clangd_completer.CheckClangdVersion( 'clangd' ),
                   equal_to( True ) )
     assert_that( clangd_completer.CheckClangdVersion( 'clangd' ),

ycmd/tests/cs/debug_info_test.py

@@ -193,14 +193,14 @@ def test_GetCompleter_RoslynFound( self ):
 
   @patch( 'ycmd.completers.cs.cs_completer.PATH_TO_OMNISHARP_ROSLYN_BINARY',
           None )
-  def test_GetCompleter_RoslynNotFound( *args ):
+  def test_GetCompleter_RoslynNotFound( self, *args ):
     assert_that( not GetCompleter( user_options_store.GetAll() ) )
 
 
   @patch( 'ycmd.completers.cs.cs_completer.FindExecutableWithFallback',
           wraps = lambda x, fb: x if x == 'roslyn' else fb )
   @patch( 'os.path.isfile', return_value = True )
-  def test_GetCompleter_RoslynFromUserOption( *args ):
+  def test_GetCompleter_RoslynFromUserOption( self, *args ):
     user_options = user_options_store.GetAll().copy(
         roslyn_binary_path = 'roslyn' )
     assert_that( GetCompleter( user_options )._roslyn_path,