So there s a nice ` pants no infer dep` directive Is there s

Question

So there s a nice ` pants no infer dep` directive Is there something like ` pants allow missing dep`

happy-kitchen-89482 · Answer

To say don t worry if you can t find a thing that provides this `import`

bitter-ability-32190 · Answer

Not currently But with a sufficient use case sounds easy to add

careful-address-89803 · Answer

pants dependency parsing will already flag weak imports those in try catch blocks which will be ignored if missing I think it would be simple enough to have a pragma flag imports as weak explicitly

high-yak-85899 · Answer

Yeah exactly like that In a couple places we have some try except style imports that I d like pants to try to infer if it can but be satisfied and carry on with the program if it can t

happy-kitchen-89482 · Answer

Today it would carry on with a warning right

bitter-ability-32190 · Answer

gt Yeah exactly like that In a couple places we have some try except style imports that I d like pants to try to infer if it can but be satisfied and carry on with the program if it can t How does today s support not suffice

high-yak-85899 · Answer

Yes but I have those elevated to error since it s usually bad coding design

high-yak-85899 · Answer

I found multiple places where folks didn t declare first party dependencies and were gathering things transitively So I like the default being error for us and explicitly declaring where it s expected

high-yak-85899 · Answer

Otherwise you have to train developers on which warnings are okay and then you re just crying wolf

bitter-ability-32190 · Answer

Right Pants already treats imports inside a try except block as dont complain about it if it can t be inferred Is that not sufficient

high-yak-85899 · Answer

Oh I hadn t noticed that I ll double check that s what s happening

bitter-ability-32190 · Answer

raised hands

high-yak-85899 · Answer

Okay I know why this wasn t happening for us and I d appreciate some guidance

high-yak-85899 · Answer

I have modules `a py` `b py` and `c py` The relationship is such that `a py` depends on `b py` which depends on `c py` In `a py` I have a statement like ```try import b except ImportError ModuleNotFoundError Totally okay to happen pass``` `b py` has a statement like ```import c``` and I was expecting pants to transitively carry through the `try except` allowance `c py` missing is actually the thing that causes `b py` import to fail Is our only recourse here to similarly wrap `import c` in `try except`

bitter-ability-32190 · Answer

The dependency parser only tracks handles direct dependencies

high-yak-85899 · Answer

Okay seems easy enough to do a ```try import c except ModuleNotFoundError as e raise e``` so that it propagates up for the handling we actually wanted

bitter-ability-32190 · Answer

I think `ImportError` is the key let me check

bitter-ability-32190 · Answer

Yeah it s specifically `ImportError` <https github com pantsbuild pants blob 7de8661340fce65ba0e4f863c2e29f1e99b98363 src python pants backend python dependency inference scripts dependency parser py L129|https github com pantsbuild pants blob 7de8661340fce65ba0e4f863c2e29f1e99b98363 ackend python dependency inference scripts dependency parser py>

high-yak-85899 · Answer

Why not `ModuleNotFoundError`

bitter-ability-32190 · Answer

man shrugging FWIW thats a subclass of `ImportError`

bitter-ability-32190 · Answer

So might be safer to use `ImportError`

bitter-ability-32190 · Answer

happy-kitchen-89482 · Answer

Yeah I think wrapping `import c` is in some sense more correct in terms of modeling what s going on

high-yak-85899 · Answer

Yup We will proceed with that