fix: skip any trailing new line when lexing

Author: sleiderr

Lib/netrc.py

@@ -2,8 +2,7 @@
 
 # Module and documentation by Eric S. Raymond, 21 Dec 1998
 
-import os
-import stat
+import os, stat
 
 __all__ = ["netrc", "NetrcParseError"]
 
@@ -23,41 +22,53 @@ def __str__(self):
 class _netrclex:
     def __init__(self, fp):
         self.lineno = 1
-        self.dontskip = False
         self.instream = fp
         self.whitespace = "\n\t\r "
         self.pushback = []
+        self.char_pushback = []
 
     def _read_char(self):
+        if self.char_pushback:
+            return self.char_pushback.pop(0)
         ch = self.instream.read(1)
         if ch == "\n":
             self.lineno += 1
         return ch
 
+    def skip_blank_lines(self):
+        fiter = iter(self._read_char, "")
+        for ch in fiter:
+            if ch == '\n':
+                self.lineno += 1
+            else:
+                self.char_pushback.append(ch)
+                return
+
     def get_token(self):
-        self.dontskip = False
         if self.pushback:
             return self.pushback.pop(0)
         token = ""
-        enquoted = False
-        while ch := self._read_char():
-            if ch == '\\':
-                ch = self._read_char()
-                token += ch
+        fiter = iter(self._read_char, "")
+        for ch in fiter:
+            if ch in self.whitespace:
                 continue
-            if ch in self.whitespace and not enquoted:
-                if token == "":
-                    continue
-                if ch == '\n':
-                    self.dontskip = True
-                return token
             if ch == '"':
-                if enquoted:
-                    return token
-                enquoted = True
-                continue
+                for ch in fiter:
+                    if ch == '"':
+                        return token
+                    elif ch == "\\":
+                        ch = self._read_char()
+                    token += ch
             else:
+                if ch == "\\":
+                    ch = self._read_char()
                 token += ch
+                for ch in fiter:
+                    if ch in self.whitespace:
+                        return token
+                    elif ch == "\\":
+                        ch = self._read_char()
+                    token += ch
         return token
 
     def push_token(self, token):
@@ -67,7 +78,7 @@ def push_token(self, token):
 class netrc:
     def __init__(self, file=None):
         default_netrc = file is None
-        if default_netrc:
+        if file is None:
             file = os.path.join(os.path.expanduser("~"), ".netrc")
         self.hosts = {}
         self.macros = {}
@@ -82,15 +93,14 @@ def _parse(self, file, fp, default_netrc):
         lexer = _netrclex(fp)
         while 1:
             # Look for a machine, default, or macdef top-level keyword
-            tt = lexer.get_token()
+            lexer.skip_blank_lines()
+            saved_lineno = lexer.lineno
+            toplevel = tt = lexer.get_token()
             if not tt:
                 break
             elif tt[0] == '#':
-                # For top level tokens, we skip line if the # is followed
-                # by a space / newline. Otherwise, we only skip the token.
-                if tt == '#' and not lexer.dontskip:
+                if lexer.lineno == saved_lineno and len(tt) == 1:
                     lexer.instream.readline()
-                    lexer.lineno += 1
                 continue
             elif tt == 'machine':
                 entryname = lexer.get_token()
@@ -101,7 +111,6 @@ def _parse(self, file, fp, default_netrc):
                 self.macros[entryname] = []
                 while 1:
                     line = lexer.instream.readline()
-                    lexer.lineno += 1
                     if not line:
                         raise NetrcParseError(
                             "Macro definition missing null line terminator.",
@@ -118,18 +127,20 @@ def _parse(self, file, fp, default_netrc):
                     "bad toplevel token %r" % tt, file, lexer.lineno)
 
             if not entryname:
-                raise NetrcParseError(
-                    "missing %r name" % tt, file, lexer.lineno)
+                raise NetrcParseError("missing %r name" % tt, file, lexer.lineno)
 
             # We're looking at start of an entry for a named machine or default.
             login = account = password = ''
             self.hosts[entryname] = {}
             while 1:
+                # Trailing blank lines would break the checks that determine if the token
+                # is the last one on its line.
+                lexer.skip_blank_lines()
+                prev_lineno = lexer.lineno
                 tt = lexer.get_token()
                 if tt.startswith('#'):
-                    if not lexer.dontskip:
+                    if lexer.lineno == prev_lineno:
                         lexer.instream.readline()
-                        lexer.lineno += 1
                     continue
                 if tt in {'', 'machine', 'default', 'macdef'}:
                     self.hosts[entryname] = (login, account, password)
@@ -170,7 +181,12 @@ def _security_check(self, fp, default_netrc, login):
 
     def authenticators(self, host):
         """Return a (user, account, password) tuple for given host."""
-        return self.hosts.get(host, self.hosts.get('default'))
+        if host in self.hosts:
+            return self.hosts[host]
+        elif 'default' in self.hosts:
+            return self.hosts['default']
+        else:
+            return None
 
     def __repr__(self):
         """Dump the class data in the format of a .netrc file."""
@@ -187,3 +203,6 @@ def __repr__(self):
                 rep += line
             rep += "\n"
         return rep
+
+if __name__ == '__main__':
+    print(netrc())

Lib/test/test_netrc.py

@@ -259,13 +259,24 @@ def test_comment_after_machine_line_hash_only(self):
             #
             """)
 
-    def test_comment_at_first_line(self):
+    def test_comment_at_first_line_trailing_new_line(self):
         self._test_comment("""
             # TEST
             machine foo.domain.com login bar password pass
             machine bar.domain.com login foo password pass
             """)
 
+    def test_comment_multiple_trailing_new_lines(self):
+        self._test_comment("""
+            # TEST
+            machine foo.domain.com login bar password pass
+
+
+            #FTP
+
+            machine bar.domain.com login foo password pass
+            """)
+
     def test_comment_at_end_of_machine_line(self):
         self._test_comment("""\
             machine foo.domain.com login bar password pass # comment