_module = 'cs112_f22_week6_linter.py version 2.0' # Place this file in the same folder as your Python files. # While you need to use this file to do your exercises, students # are not expected to look at nor to understand any code in this file. # bannedTokens list for week 6 _bannedTokens = ( 'statistics,' + 'class,del,' + 'global,lambda,nonlocal,' + #'with,' + '__import__,ascii,bin,bytearray,bytes,callable,' + 'classmethod,compile,delattr,dict,dir,' + 'eval,literal_eval,exec,filter,format,frozenset,getattr,globals,' + 'hasattr,hash,help,hex,id,issubclass,iter,' + 'map,memoryview,object,oct,' + 'property,set,' + 'setattr,staticmethod,super,' + 'try,except,'+ 'vars,importlib,imp') _conversions = { 'classdef': 'class', } import math, sys, traceback, inspect import ast import platform class _AssertionError(AssertionError): pass def _formatError(header, file, line, fn, text, msg, expl): messages = ['\n******************************'] if (header): messages.append(header) if (file): messages.append(' File: "%s"' % file) if (line): messages.append(' Line: %d' % line) if (fn): messages.append(' Function: %s' % fn) if (text): messages.append(' Code: %s' % text.strip()) messages.append(' Error: %s' % msg) if (expl): messages.append(' Hint: %s' % expl) message = '\n'.join(messages) return message class _LintError(Exception): def __init__(self, errors): messages = [ '' ] for i,e in enumerate(errors): (msg, file, line, fn, text, expl) = e header = 'LintError #%d of %d:' % (i+1, len(errors)) message = _formatError(header, file, line, fn, text, msg, expl) messages.append(message) message = ''.join(messages) super().__init__(message) class _Linter(ast.NodeVisitor): def __init__(self, code=None, filename=None, bannedTokens=None): self.code = code self.filename = filename self.bannedTokens = set(bannedTokens or [ ]) self.issuedRoundOopsMessage = False ifMain = ast.parse("if __name__ == '__main__': main()") self.allowableConditional = ast.dump(ifMain.body[0]) def lint(self): print('Linting... ', end='') self.errors = [ ] if (self.code == None): with open(self.filename, 'rt', encoding="utf-8") as f: try: self.code = f.read() except e: msg = 'Error when trying to read file:\n' + str(e) expl = ("This usually means something got corrupted in " "your file\n\t\t\t and you should remove the " "corrupted portions or\n\t\t\t start a new file.") self.oops(msg,expl) raise _LintError(self.errors) if (self.code in [None,'']): self.oops('Could not read code from "%s"' % self.filename) raise _LintError(self.errors) try: self.tree = ast.parse(self.code) except Exception as e: self.oops(e) self.oops("Unexpected linting error! See instructors for help.") raise _LintError(self.errors) #print(ast.dump(self.tree, indent=4)) self.lintLineWidths() # Strips out trailing whitespace self.lintSymbols() # Things that are easier to catch in text self.lintTopLevel() # Only allow import, def, class, or if...main() self.lintAllLevels() # AST diving if (self.errors != [ ]): raise _LintError(self.errors) print("Passed!") def lintLineWidths(self): lines = self.code.splitlines() for i in range(len(lines)): line = lines[i].rstrip() if (len(line) > 80): msg = 'Line width is >80 characters' expl = ("You may not have a line of code " "longer than 80 characters.") self.oops(msg, expl, line=i+1, text='\n'+line[:81]+'...') def lintSymbols(self): symbols = {'[',']','{','}','@','&','^','|'} prohibitedSymbols = symbols.intersection(self.bannedTokens) lines = self.code.splitlines() for i in range(len(lines)): line = lines[i] if '#' in line: line = line.split('#')[0] for token in prohibitedSymbols: if token in line: msg = f'Disallowed token: {token}' expl = ("You are using a feature of Python that is " "not allowed in this\n\t\t\tassignment. You will " "need to solve this assignment without using " "\n\t\t\tthat feature.") self.oops(msg, expl, line = i, text = line) def lintTopLevel(self): exemptNodeTypes = (ast.ClassDef, ast.FunctionDef, ast.Import, ast.ImportFrom) tripleQuotes = ('"""',"'''",'"',"'") for node in self.tree.body: if (type(node) not in exemptNodeTypes and (ast.dump(node) != self.allowableConditional)): text = ast.get_source_segment(self.code, node, padded = True).strip() if text[:3] in tripleQuotes and text[-3:] in tripleQuotes: continue msg = "Top-level code that is not import, def, or class." expl = ("All of your code should be inside of a function. " "If you want to make sure\n\t\t\tsomething runs " "every time, add it to main().") self.oops(msg, expl, line=node.lineno, text=text, node=node) def lintAllLevels(self): try: self.visit(self.tree) except: msg = f'Unexpected lint error!' expl = ("Something unexpected is happening, but unfortunately " "we can't pinpoint where or what. You may be trying to call " "something that isn't callable (for example, trying to " "call an integer like a function, like 5(True). Check " "your parentheses!)") #text = ast.get_source_segment(self.code, node, padded = True) self.oops(msg, expl) def visit_Import(self, node): for n in node.names: self.checkToken(n.name, node) self.generic_visit(node) def visit_FunctionDef(self, node): self.checkToken(node.name, node) self.generic_visit(node) def visit_Call(self, node): if hasattr(node.func, "id"): self.checkToken(node.func.id, node) elif hasattr(node.func, "value"): self.visit(node.func.value) else: msg = f'Unexpected lint error!' expl = ("Something unexpected is happening on this line. " "As a result, our linter can't understand it. Look " "carefully, and if you can't see anything wrong, " "ask the instructors and give them your code and this " "error message.") text = ast.get_source_segment(self.code, node, padded = True) self.oops(msg, expl, line = node.lineno, text = text, node = node) self.generic_visit(node) def visit_Attribute(self, node): if hasattr(node.value, "id"): self.checkToken(node.value.id, node) self.checkToken(node.attr, node) self.generic_visit(node) #def visit_Expr(self, node): # self.generic_visit(node) #def visit_With(self, node): # self.generic_visit(node) def generic_visit(self, node): token = str(type(node)).split('.')[-1].split("'")[0].lower() self.checkToken(token, node) super().generic_visit(node) def checkToken(self, token, node): token = _conversions.get(token, token) if token == 'round': self.roundOops(node) elif token in self.bannedTokens: msg = f'Disallowed token: {token}' expl = ("You are using a feature of Python that is not allowed " "in this\n\t\t\tassignment. You will need to solve this " "assignment without using\n\t\t\tthat feature.") text = ast.get_source_segment(self.code, node, padded = True) self.oops(msg, expl, line = node.lineno, text = text, node = node) def roundOops(self, node): msg = 'Do not use builtin "round" in Python 3' if (self.issuedRoundOopsMessage): msg += ' (see above for details)' expl = '' else: self.issuedRoundOopsMessage = True expl= ('The behavior of "round" in Python 3 may be unexpected. ' '\n\t\t\tFor example: ' '\n\t\t\t round(1.5) returns 2 ' '\n\t\t\t round(2.5) returns 2 ' '\n\t\t\tInstead, in 15-112, use the roundHalfUp(d) ' 'function provided. ') text = ast.get_source_segment(self.code, node, padded = True) self.oops(msg, expl, line = node.lineno, text = text, node=node) def oops(self, msg, expl=None, line=None, fn=None, text=None, node=None): self.errors.append((msg, self.filename, line, fn, text, expl)) def lint(code=None, filename=None, bannedTokens=_bannedTokens): if (isinstance(bannedTokens, str)): bannedTokens = bannedTokens.split(',') if ((code == None) and (filename == None)): try: module = None frame = inspect.stack()[1] module = inspect.getmodule(frame[0]) if ((module == None) or (module.__file__ == None)): # this may help, or maybe not (sigh) module = sys.modules['__main__'] # the next line may fail (sigh) filename = module.__file__ except: raise Exception('lint cannot find module/file to lint!') try: _Linter(code=code, filename=filename, bannedTokens=bannedTokens).lint() except _LintError as lintError: # just 'raise lintError' for cleaner traceback lintError.__traceback__ = None raise lintError def _printImportReport(): import platform, datetime #print('Importing %s in Python %s' % (_module, platform.python_version())) (major, minor, micro, releaselevel, serial) = sys.version_info if (major < 3): raise Exception("You must use Python 3, not Python 2!") if (minor < 7): raise Exception("You must use Python 3.7 or newer!") if (__name__ != '__main__'): _printImportReport()