Add --warn-implicit-any #3141

pkch · 2017-04-07T09:55:17Z

Experimental: attempt to address parts of #2901

gvanrossum · 2017-04-13T01:58:06Z

Since you say "experimental" I'm not reviewing this yet and I've added "[WIP]" to the subject. (I think GMail may even thread notifications correctly because of the brackets.)

pkch · 2017-04-27T08:59:45Z

It's far from perfect, but since it caught quite a few unintentional Any expansions in my code, maybe it's worth considering.

gvanrossum · 2017-05-10T22:18:58Z

I propose that @ddfisher should review this.

ilinum

I provided some cosmetic feedback but I unfortunately, I can't give any deep review since my knowledge of mypy is limited. Perhaps, @ddfisher can help.

Overall, I think this feature is great! We should try to finish it up and merge it.
Maybe we can name the flag --warn-implicit-any-generic or --disallow-implicit-any-generic.

ilinum · 2017-05-24T18:29:45Z

mypy/semanal.py

@@ -3251,12 +3251,15 @@ def name_already_defined(self, name: str, ctx: Context) -> None:
        self.fail("Name '{}' already defined".format(name), ctx)

    def fail(self, msg: str, ctx: Context, serious: bool = False, *,
-             blocker: bool = False) -> None:
+             blocker: bool = False, implicit_any: bool = False) -> None:


It seems like adding an extra parameter to fail function might not be the best way to do it.
I would try to keep this function generic for any kind of failures.

Perhaps, you can check if the error is in the caller.

I agree. Unfortunately, I need to suppress the error message based on the information (options, and whether the module being checked is a stub) that's unavailable inside TypeAnalyser methods where the error occurs. I am not sure what the best fix for this would be. If I don't add an extra parameter to fail, I'll have to pass all this information into TypeAnalyser, but that's not good either since TypeAnalyser should not care about those details.

ilinum · 2017-05-24T18:31:20Z

mypy/semanal.py

@@ -3680,7 +3683,14 @@ def analyze(self, type: Type) -> None:
            analyzer = TypeAnalyserPass3(self.fail)
            type.accept(analyzer)

-    def fail(self, msg: str, ctx: Context, *, blocker: bool = False) -> None:
+    def fail(self, msg: str, ctx: Context, *, blocker: bool = False,
+             implicit_any: bool = False) -> None:


Same as above - not sure if it's good to have an implicit_any parameter.

ilinum · 2017-05-24T18:32:05Z

mypy/semanal.py

+            if not self.options.warn_implicit_any or self.errors.file.endswith('.pyi'):
+                return
+            # TempNode, so must have already reported in the first pass
+            if ctx.get_line() == -1:


This seems like a hack but I couldn't find a way to do it better. Perhaps, someone with more mypy experience may help with that?

Are you talking about checking for stubs or checking for temporary nodes? I don't know if I would cosnider either of them a hack (my threshold of hackiness in the error-reporting code is much higher than in normal code); but if anyone has a better solution, it would be nice.

ilinum · 2017-05-24T18:33:52Z

mypy/typeanal.py

@@ -174,6 +175,7 @@ def visit_unbound_type(self, t: UnboundType) -> Type:
                return self.analyze_callable_type(t)
            elif fullname == 'typing.Type':
                if len(t.args) == 0:
+                    self.implicit_any('Type without type args', t)


There doesn's seem to be a test case for this. It's probably worth having one.

ilinum · 2017-05-24T18:36:50Z

mypy/typeanal.py

@@ -183,6 +185,7 @@ def visit_unbound_type(self, t: UnboundType) -> Type:
                if self.nesting_level > 0:
                    self.fail('Invalid type: ClassVar nested inside other type', t)
                if len(t.args) == 0:
+                    self.implicit_any('ClassVar without type args', t)


There doesn's seem to be a test case for this. It's probably worth having one.

ilinum · 2017-05-24T18:37:01Z

mypy/typeanal.py

@@ -220,6 +224,7 @@ def visit_unbound_type(self, t: UnboundType) -> Type:
                    # context. This is slightly problematic as it allows using the type 'Any'
                    # as a base class -- however, this will fail soon at runtime so the problem
                    # is pretty minor.
+                    self.implicit_any('Assigning value of type Any', t)


There doesn's seem to be a test case for this. It's probably worth having one.

ilinum · 2017-05-24T18:40:06Z

mypy/typeanal.py

@@ -259,6 +264,7 @@ def visit_unbound_type(self, t: UnboundType) -> Type:
                                            fallback=instance)
                return instance
        else:
+            self.implicit_any('Fallback', t)


This seems to be a debug statement.

Hmm, how can you tell that this cannot happen in a production run?

ilinum · 2017-05-24T18:45:38Z

mypy/semanal.py

+    def fail(self, msg: str, ctx: Context, *, blocker: bool = False,
+             implicit_any: bool = False) -> None:
+        if implicit_any:
+            if not self.options.warn_implicit_any or self.errors.file.endswith('.pyi'):


There should be a better way for checking for stub files but I can't seem to find it.

Why are you limiting the flag to non-stub files anyway?

I also can't find it.

In stub files, a lot of the times the type argument in genertic types is omitted (e.g., Union[type, Tuple], def f() -> tuple:, def g() -> Iterable:, etc.). There'll be hundreds of warnings like this, making the flag unusable.
I am sure we don't want to change the stubs to avoid implicit Any (and even if we did, that change would have to happen first, before warn_implicit_any starts paying attention to stubs).

ilinum · 2017-05-24T19:40:26Z

Just remembered this doesn't cover the cases when not all type parameters are specified.

So like Dict[str] would not be covered.

ilevkivskyi · 2017-05-28T07:44:42Z

@ilinum

So like Dict[str] would not be covered.

What do you mean by this? Dict[str] is already an error.

ilinum · 2017-05-30T17:57:38Z

@ilevkivskyi you are right. I looked at the code and it didn't seem like it would handle these kind of errors. But I just ran mypy now and it is an error.

ilinum · 2017-06-14T02:33:55Z

@pkch are you interested in working on this?

pkch · 2017-06-14T09:05:53Z

Ah yes, I'm going to make the fixes I'm aware of. However, I'm still not sure if the overall approach is acceptable.

(--disallow-any=generics) This code is based on python#3141 by pkch. This option disallows implicit Anys from omitted type parameters to generic types. For instance, `def x() -> List` would produce an error while `def x() -> List[Any]` is allowed. Note that with the flag enabled builtin generic types such as `list` and `set` are also forbidden.

ilinum · 2017-06-30T05:14:27Z

I reworked this PR and submitted it as #3637.

Closing this PR in favor of the new one.

(--disallow-any=generics) This code is based on #3141 by pkch. This option disallows implicit Anys from omitted type parameters to generic types. For instance, `def x() -> List` would produce an error while `def x() -> List[Any]` is allowed. Note that with the flag enabled builtin generic types such as `list` and `set` are also forbidden.

pkch mentioned this pull request Apr 7, 2017

--warn-return-any is too specialized #2901

Closed

gvanrossum changed the title ~~Add --warn-implicit-any~~ [WIP] Add --warn-implicit-any Apr 13, 2017

pkch mentioned this pull request Apr 26, 2017

Reliable version of os.replace for Windows (wait/retry loop) #3239

Closed

Add --warn-implicit-any

6292edc

pkch force-pushed the noargs-any branch from 468bd49 to 6292edc Compare April 27, 2017 08:57

pkch changed the title ~~[WIP] Add --warn-implicit-any~~ Add --warn-implicit-any Apr 27, 2017

gvanrossum requested a review from ddfisher May 10, 2017 22:19

This was referenced May 22, 2017

Disallow implicit Any types from Silent Imports #3405

Merged

Unbound parameters of type aliases silently default to Any #3386

Closed

Flags for disabling Any types #3427

Closed

ilinum reviewed May 24, 2017

View reviewed changes

pkch mentioned this pull request May 24, 2017

Fix crash when annotating callable definition location #3375

Merged

ilinum mentioned this pull request May 27, 2017

Flag for disallowing Any #3470

Closed

ilinum mentioned this pull request May 30, 2017

Omitted Generics Should Be Disallowed #3469

Closed

gvanrossum assigned ddfisher Jun 5, 2017

pkch added 2 commits June 24, 2017 09:39

Merge branch 'master' into noargs-any

abe4132

CR: add tests

aceeca3

ilinum mentioned this pull request Jun 30, 2017

Option to disallow omitting type parameters of generic types #3637

Merged

ilinum closed this Jun 30, 2017

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Add --warn-implicit-any #3141

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Add --warn-implicit-any #3141

Add --warn-implicit-any #3141

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ilinum commented May 24, 2017

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