Logic to have various kind of suggestions in case of errors (NameError, AttributeError, ImportError, TypeError, ValueError, SyntaxError, MemoryError, OverflowError, IOError, OSError).
Inspired by "Did you mean" for Ruby (Explanation, Github Page), this is a simple implementation for/in Python. I wanted to see if I could mess around and create something similar in Python and it seems to be possible.
Once the package is installed (see below), the logic adding suggestions can be invoked in different ways:
sys.excepthook : just call didyoumean_enablehook() and you'll have the suggestions for any uncaught exception:>>> abc = 3
>>> abcd
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'abcd' is not defined
>>> didyoumean.didyoumean_api.didyoumean_enablehook()
>>> abcd
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'abcd' is not defined. Did you mean 'abc' (local)?didyoumean_postmortem() on the last uncaught exception during interactive sessions:>>> abc = 3
>>> abcd
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'abcd' is not defined
>>> didyoumean.didyoumean_api.didyoumean_postmortem()
NameError("name 'abcd' is not defined. Did you mean 'abc' (local)?",)didyoumean_contextmanager():>>> with didyoumean.didyoumean_api.didyoumean_contextmanager():
... abcd
...
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
NameError: name 'abcd' is not defined. Did you mean 'abc' (local)@didyoumean decorator before any function (the main() could be a good choice) and you'll have the suggestions for any exception happening through a call to that method.>>> @didyoumean.didyoumean_api.didyoumean_decorator
... def foo(): return abcd
...
>>> foo()
Traceback (most recent call last):
File "<stdin>", line 2, in foo
NameError: global name 'abcd' is not defined. Did you mean 'abc' (global)?The API does not look great and may be updated in the near future.
_More examples can be found from the test file didyoumean/didyoumean_sugg_tests.py._
def my_func(foo, bar):
return foob
my_func(1, 2)
#>>> Before: NameError("global name 'foob' is not defined",)
#>>> After: NameError("global name 'foob' is not defined. Did you mean 'foo' (local)?",)leng([0])
#>>> Before: NameError("name 'leng' is not defined",)
#>>> After: NameError("name 'leng' is not defined. Did you mean 'len' (builtin)?",)import math
maths.pi
#>>> Before: NameError("name 'maths' is not defined",)
#>>> After: NameError("name 'maths' is not defined. Did you mean 'math' (local)?",)passs
#>>> Before: NameError("name 'passs' is not defined",)
#>>> After: NameError("name 'passs' is not defined. Did you mean 'pass' (keyword)?",)def my_func():
foo = 1
foob +=1
my_func()
#>>> Before: UnboundLocalError("local variable 'foob' referenced before assignment",)
#>>> After: UnboundLocalError("local variable 'foob' referenced before assignment. Did you mean 'foo' (local)?",)class Duck():
def __init__(self):
quack()
def quack(self):
pass
d = Duck()
#>>> Before: NameError("global name 'quack' is not defined",)
#>>> After: NameError("global name 'quack' is not defined. Did you mean 'self.quack'?",)import math
pi
#>>> Before: NameError("name 'pi' is not defined",)
#>>> After: NameError("name 'pi' is not defined. Did you mean 'math.pi'?",)string.ascii_lowercase
#>>> Before: NameError("name 'string' is not defined",)
#>>> After: NameError("name 'string' is not defined. Did you mean to import string first?",)choice
#>>> Before: NameError("name 'choice' is not defined",)
#>>> After: NameError("name 'choice' is not defined. Did you mean 'choice' from random (not imported)?",)assert j ** 2 == -1
#>>> Before: NameError("name 'j' is not defined",)
#>>> After: NameError("name 'j' is not defined. Did you mean '1j' (imaginary unit)?",)lst = [1, 2, 3]
lst.appendh(4)
#>>> Before: AttributeError("'list' object has no attribute 'appendh'",)
#>>> After: AttributeError("'list' object has no attribute 'appendh'. Did you mean 'append'?",)import math
math.pie
#>>> Before: AttributeError("'module' object has no attribute 'pie'",)
#>>> After: AttributeError("'module' object has no attribute 'pie'. Did you mean 'pi'?",)lst = [1, 2, 3]
lst.max()
#>>> Before: AttributeError("'list' object has no attribute 'max'",)
#>>> After: AttributeError("'list' object has no attribute 'max'. Did you mean 'max(list)'?",)lst = [1, 2, 3]
lst.add(4)
#>>> Before: AttributeError("'list' object has no attribute 'add'",)
#>>> After: AttributeError("'list' object has no attribute 'add'. Did you mean 'append'?",)lst = [1, 2, 3]
lst.get(5, None)
#>>> Before: AttributeError("'list' object has no attribute 'get'",)
#>>> After: AttributeError("'list' object has no attribute 'get'. Did you mean 'obj[key]' with a len() check or try: except: KeyError or IndexError?",)from maths import pi
#>>> Before: ImportError('No module named maths',)
#>>> After: ImportError("No module named maths. Did you mean 'math'?",)from math import pie
#>>> Before: ImportError('cannot import name pie',)
#>>> After: ImportError("cannot import name pie. Did you mean 'pi'?",)from itertools import pi
#>>> Before: ImportError('cannot import name pi',)
#>>> After: ImportError("cannot import name pi. Did you mean 'from math import pi'?",)def my_func(abcde):
pass
my_func(abcdf=1)
#>>> Before: TypeError("my_func() got an unexpected keyword argument 'abcdf'",)
#>>> After: TypeError("my_func() got an unexpected keyword argument 'abcdf'. Did you mean 'abcde'?",)lst = [1, 2, 3]
lst(0)
#>>> Before: TypeError("'list' object is not callable",)
#>>> After: TypeError("'list' object is not callable. Did you mean 'list[value]'?",)def my_func(a):
pass
my_func[1]
#>>> Before: TypeError("'function' object has no attribute '__getitem__'",)
#>>> After: TypeError("'function' object has no attribute '__getitem__'. Did you mean 'function(value)'?",)'Foo{}'.format('bar')
#>>> Before: ValueError('zero length field name in format',)
#>>> After: ValueError('zero length field name in format. Did you mean {0}?',)import datetime
datetime.datetime.strptime("%d %b %y", "30 Nov 00")
#> Before: ValueError("time data '%d %b %y' does not match format '30 Nov 00'",)
#> After: ValueError("time data '%d %b %y' does not match format '30 Nov 00'. Did you mean to swap value and format parameters?",)from __future__ import divisio
#>>> Before: SyntaxError('future feature divisio is not defined',)
#>>> After: SyntaxError("future feature divisio is not defined. Did you mean 'division'?",)return
#>>> Before: SyntaxError("'return' outside function", ('<string>', 1, 0, None))
#>>> After: SyntaxError("'return' outside function. Did you mean to indent it, 'sys.exit([arg])'?", ('<string>', 1, 0, None))range(99999999999)
#>>> Before: MemoryError()
#>>> After: MemoryError(". Did you mean 'xrange'?",)range(999999999999999)
#>>> Before: OverflowError('range() result has too many items',)
#>>> After: OverflowError("range() result has too many items. Did you mean 'xrange'?",)os.listdir('~')
#>>> Before: OSError(2, 'No such file or directory')
#>>> After: OSError(2, "No such file or directory. Did you mean '/home/user' (calling os.path.expanduser)?")global rec
def rec(n): return rec(n-1)
rec(0)
#>>> Before: RuntimeError('maximum recursion depth exceeded',)
#>>> After: RuntimeError('maximum recursion depth exceeded. Did you mean to avoid recursion (cf http://neopythonic.blogspot.fr/2009/04/tail-recursion-elimination.html), increase the limit with `sys.setrecursionlimit(limit)` (current value is 1000)?',)The package is available on Pypi as BetterErrorMessages.
Installation can be done from the package index with pip install BetterErrorMessages.
Installation from sources can be done just as easily:
git clone https://github.com/SylvainDe/DidYouMean-Python.git
cd DidYouMean-Python
git install .You can have the suggestions automatically in your interactive sessions by adding the following code in your ${PYTHONSTARTUP} file:
try:
import didyoumean
except ImportError:
print("Did you mean to install BetterErrorMessages first (`pip install BetterErrorMessages`)")
else:
didyoumean.didyoumean_api.didyoumean_enablehook()All external APIs (decorator, hook, etc) use the same logic behind the scene. It works in a pretty simple way : when an exception happens, we try to get the relevant information out of the error message and of the backtrace to find the most relevant suggestions. To filter the best suggestions out of everything in case of fuzzy match, I am currently using difflib.
"Did you mean" for Ruby (links above)
dutc/didyoumean : a quite similar project developed in pretty much the same time. A few differences though : written in C, works only for AttributeError, etc.
Commit in iPython to add suggestions in case of errors
Ideas from the Python Ideas mailing list : "Improve error message when missing 'self' in method definition", "Better error messages" part 1 and part 2
TheF*ck : Correct and execute your previous shell command.
PyDidYouMean : Improve "file/command not found" errors with suggestions.
Qix-/better-exceptions : Pretty and useful exceptions in Python
danrobinson/tracestack : Search your Python error messages on the web.
cfbolz/syntaxerrors : Python parser that can recover from errors (also, cfbolz added many suggestions for errors to PyPy).
In Raymond Hettinger's PyconCA keynote, the part about the hint builtin (at 14 minutes) looks a lot like didyoumean_postmortem.
Feedback is welcome, feel free to :
Also, pull-requests are welcome to :
As for the technical details :