Question Compilation error: ToSchema called Option::unwrap() on a None value

[AnatolyBuga]

I am getting an error on

this function takes 1 argument but 0 arguments were supplied
    --> ultibi\ultibi_core\src\datarequest.rs:34:10
     |
34   | #[derive(ToSchema)]
     |          ^^^^^^^^ an argument is missing
     |
note: associated function defined here
    --> C:\Users\Anato\.cargo\registry\src\github.com-1ecc6299db9ec823\utoipa-3.1.2\src\openapi\schema.rs:1057:12
     |
1057 |     pub fn items<I: Into<RefOr<Schema>>>(mut self, component: I) -> Self {
     |            ^^^^^
     = note: this error originates in the derive macro `ToSchema` (in Nightly builds, run with -Z macro-backtrace for more info)
help: provide the argument
     |
34   | #[derive(ToSchema(/* value */))]

As far as I can see ToShema derive doesn't take any arguments. Any thoughts?

[AnatolyBuga]

This is my code, although alot of type aliases - they are mostly strings and maps:

use utoipa::ToSchema;
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
#[serde(tag = "type")]
#[derive(ToSchema)]
pub struct AggregationRequest {
    // general fields
    #[serde(default)]
    pub name: Option<String>,
    /// Measure: (Name, Action) where Name will be looked up in
    /// MeasuresMap of the DataSet
    pub measures: Vec<(MeasureName, AggregationName)>,
    pub groupby: Vec<String>,
    #[serde(default)]
    pub filters: AndOrFltrChain,
    #[serde(default)]
    pub overrides: Vec<Override>,
    #[serde(default, alias = "additionalRows")]
    pub add_row: AdditionalRows,
    #[serde(default)]
    pub calc_params: CPM,
    /// drop rows where all results are NULL or 0
    #[serde(default)]
    pub hide_zeros: bool,
    /// Show totals
    #[serde(default)]
    pub totals: bool,
}

[juhaku]

This is coming from the tuple syntax within your struct and is related to #330, #391, #176 and is fixed in #541.

   /// Measure: (Name, Action) where Name will be looked up in
   /// MeasuresMap of the DataSet
   pub measures: Vec<(MeasureName, AggregationName)>,

Tuple support will be available after next release, but can be accessed now by pointing the cargo dependency to the master for time being.

[AnatolyBuga]

@juhaku great, thank you very much.

[AnatolyBuga]

@juhaku , sorry, another issue followed directly from that one. Happy to put it in a separate issue though if that helps.
AggregationRequest defined as above.

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
#[serde(untagged)]
#[cfg_attr(feature = "openapi", derive(ToSchema))]
pub enum ComputeRequest {
    Aggregation(AggregationRequest),
    Breakdown,
}

This fails to compile with:

error: proc-macro derive panicked
  --> ultibi\ultibi_core\src\datarequest.rs:19:40
   |
19 | #[cfg_attr(feature = "openapi", derive(utoipa::ToSchema))]
   |                                        ^^^^^^^^^^^^^^^^
   |
   = help: message: called `Option::unwrap()` on a `None` value

error: could not compile `ultibi_core` due to previous error

[juhaku]

Happy to put it in a separate issue though if that helps.

We can continue on this thread as well. 🙂

Interesting, that still does not tell enough what is going on. How does the AggregationRequest look? what attribute is defined over it?

[AnatolyBuga]

@juhaku thanks for quick reply.

I will put together a proper reproducible example.

[AnatolyBuga]

@juhaku , here we go:

use serde::Deserialize;
use serde::Serialize;

pub fn example() {
    ()
}


#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash, utoipa::ToSchema)]
#[serde(tag = "type")]
pub struct AggregationRequest {
    #[serde(default)]
    pub name: Option<String>,
    pub measures: Vec<(String, String)>
}

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash, utoipa::ToSchema)]
#[serde(untagged)]
pub enum ComputeRequest {
    Aggregation(AggregationRequest),
    Breakdown,
}

And:

serde = { version="*", features = ["derive", "rc"] }
serde_json = { version="*" }
utoipa = { git ="https://github.com/juhaku/utoipa", features = ["actix_extras"] }

[juhaku]

Thanks for the example 🙂 , this is a bug introduced here: #533

This makes me wonder why the parsing is getting to this point where it is now giving error.

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash, utoipa::ToSchema)]
#[serde(untagged)]
pub enum ComputeRequest {
    Aggregation(AggregationRequest),
    Breakdown, /// <-- this causes the error, 
}

I need to investigate what is going on here, this scenario should be possible to my knowledge 🤔

[juhaku]

Moreover it is caused by the #[serde(untagged)] attribute. I need to check whether there is something that can be done to fix it or whether this scenario is actually not possible with OpenAPI. Without #[serde(untagged)] it will work as it should.

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash, utoipa::ToSchema)]
#[serde(untagged)] // <-- here
pub enum ComputeRequest {
    Aggregation(AggregationRequest),
    Breakdown, /// <-- this causes the error, 
}

[juhaku]

@AnatolyBuga And there you go, fix is on the way landing to master soon by #545.

[AnatolyBuga]

@juhaku thank you so much for promptly fixing this, and for the whole amazing library too.