Commit a9407b6
Display the correct signature for a decorated function in Python 3
This patch changes it so that `inspect.signature` is used instead of
`inspect.getfullargspec` to get a function's signature, when using Python 3.
Python 3.3 introduced the `inspect.signature` function as a new way to get the
signature of a function (as an alternative to `inspect.getargspec` and
`inspect.getfullargspec`). `inspect.signature` has the advantage that it
preserves the signature of a decorated function if `functools.wraps` is used to
decorated the wrapper function. Having a function's signature available is very
hepful, especially when testing things out in a REPL.1 parent 286fd36 commit a9407b6
1 file changed
Lines changed: 51 additions & 3 deletions
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -250,11 +250,10 @@ def getfuncprops(func, f): | |||
| 250 | 250 | return None | |
| 251 | 251 | try: | |
| 252 | 252 | if py3: | |
| 253 | - argspec = inspect.getfullargspec(f) | ||
| 253 | + argspec = get_argspec_from_signature(f) | ||
| 254 | 254 | else: | |
| 255 | - argspec = inspect.getargspec(f) | ||
| 255 | + argspec = list(inspect.getargspec(f)) | ||
| 256 | 256 | ||
| 257 | - argspec = list(argspec) | ||
| 258 | 257 | fixlongargs(f, argspec) | |
| 259 | 258 | if len(argspec) == 4: | |
| 260 | 259 | argspec = argspec + [list(), dict(), None] | |
@@ -284,6 +283,55 @@ def is_callable(obj): | |||
| 284 | 283 | return callable(obj) | |
| 285 | 284 | ||
| 286 | 285 | ||
| 286 | + def get_argspec_from_signature(f): | ||
| 287 | + """Get callable signature from inspect.signature in argspec format. | ||
| 288 | + | ||
| 289 | + inspect.signature is a Python 3 only function that returns the signature of | ||
| 290 | + a function. Its advantage over inspect.getfullargspec is that it returns | ||
| 291 | + the signature of a decorated function, if the wrapper function itself is | ||
| 292 | + decorated with functools.wraps. | ||
| 293 | + | ||
| 294 | + """ | ||
| 295 | + args = [] | ||
| 296 | + varargs = varkwargs = None | ||
| 297 | + defaults = [] | ||
| 298 | + kwonly = [] | ||
| 299 | + kwonly_defaults = {} | ||
| 300 | + annotations = {} | ||
| 301 | + | ||
| 302 | + signature = inspect.signature(f) | ||
| 303 | + for parameter in signature.parameters.values(): | ||
| 304 | + if parameter.annotation is not inspect._empty: | ||
| 305 | + annotations[parameter.name] = parameter.annotation | ||
| 306 | + | ||
| 307 | + if parameter.kind == inspect._ParameterKind.POSITIONAL_OR_KEYWORD: | ||
| 308 | + args.append(parameter.name) | ||
| 309 | + if parameter.default is not inspect._empty: | ||
| 310 | + defaults.append(parameter.default) | ||
| 311 | + elif parameter.kind == inspect._ParameterKind.POSITIONAL_ONLY: | ||
| 312 | + args.append(parameter.name) | ||
| 313 | + elif parameter.kind == inspect._ParameterKind.VAR_POSITIONAL: | ||
| 314 | + varargs = parameter.name | ||
| 315 | + elif parameter.kind == inspect._ParameterKind.KEYWORD_ONLY: | ||
| 316 | + kwonly.append(parameter.name) | ||
| 317 | + kwonly_defaults[parameter.name] = parameter.default | ||
| 318 | + elif parameter.kind == inspect._ParameterKind.VAR_KEYWORD: | ||
| 319 | + varkwargs = parameter.name | ||
| 320 | + | ||
| 321 | + # inspect.getfullargspec returns None for 'defaults', 'kwonly_defaults' and | ||
| 322 | + # 'annotations' if there are no values for them. | ||
| 323 | + if not defaults: | ||
| 324 | + defaults = None | ||
| 325 | + | ||
| 326 | + if not kwonly_defaults: | ||
| 327 | + kwonly_defaults = None | ||
| 328 | + | ||
| 329 | + if not annotations: | ||
| 330 | + annotations = None | ||
| 331 | + | ||
| 332 | + return [args, varargs, varkwargs, defaults, kwonly, kwonly_defaults, annotations] | ||
| 333 | + | ||
| 334 | + | ||
| 287 | 335 | get_encoding_line_re = LazyReCompile(r'^.*coding[:=]\s*([-\w.]+).*$') | |
| 288 | 336 | ||
| 289 | 337 | ||
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