Does anyone know how to properly quote a Rust enum as arg in Powershell?

tamaro-skaljic · July 9, 2025, 3:15pm

In bash you can use '{ "North": {} }' if you want to provide the North variant of an enum as CLI arg but that isn't working on Windows in Powershell.

jofas · July 9, 2025, 6:31pm

How is your program parsing CLI arguments? What is the error in Powershell?

tamaro-skaljic · July 9, 2025, 9:16pm

Hello jofas, thank you for responding to the topic. I thought that “rust enum” and “powershell” were sufficient, so I didn't provide more information.

It is not my program, but an open source program – unfortunately, even the developers have no idea what the Powershell quotation rules are.

The CLI is using Clap's ArgMatches:

github.com/clockworklabs/SpacetimeDB

crates/cli/src/subcommands/call.rs

master


      
          let database_identity = api.con.database_identity;
          let database = &api.con.database;
          
          let module_def: ModuleDef = api.module_def().await?.try_into()?;
          
          let reducer_def = module_def
              .reducer(&**reducer_name)
              .ok_or_else(|| anyhow::Error::msg(no_such_reducer(&database_identity, database, reducer_name, &module_def)))?;
          
          // String quote any arguments that should be quoted
          let arguments = arguments
              .unwrap_or_default()
              .zip(&*reducer_def.params.elements)
              .map(|(argument, element)| match &element.algebraic_type {
                  AlgebraicType::String if !argument.starts_with('\"') || !argument.ends_with('\"') => {
                      format!("\"{}\"", argument)
                  }
                  _ => argument.to_string(),
              });
          
          let arg_json = format!("[{}]", arguments.format(", "));

The server receives a ByteString (see bytestring crate) and is using Serde for deserialization:

github.com/clockworklabs/SpacetimeDB

crates/core/src/host/mod.rs

master


      
          #[error("invalid arguments for reducer {reducer}: {err}")]
          pub struct InvalidReducerArguments {
              #[source]
              err: anyhow::Error,
              reducer: Box<str>,
          }
          
          fn from_json_seed<'de, T: serde::de::DeserializeSeed<'de>>(s: &'de str, seed: T) -> anyhow::Result<T::Value> {
              let mut de = serde_json::Deserializer::from_str(s);
              let mut track = serde_path_to_error::Track::new();
              let out = seed
                  .deserialize(serde_path_to_error::Deserializer::new(&mut de, &mut track))
                  .context(track.path())?;
              de.end()?;
              Ok(out)
          }
          
          /// Tags for each call that a `WasmInstanceEnv` can make.
          #[derive(Debug, Display, Enum, Clone, Copy, strum::AsRefStr)]
          pub enum AbiCall {
              TableIdFromName,

The trace is:

https://github.com/clockworklabs/SpacetimeDB/blob/master/crates/client-api/src/routes/database.rs#L111
https://github.com/clockworklabs/SpacetimeDB/blob/master/crates/core/src/host/module_host.rs#L901
https://github.com/clockworklabs/SpacetimeDB/blob/master/crates/core/src/host/module_host.rs#L860
https://github.com/clockworklabs/SpacetimeDB/blob/master/crates/core/src/host/mod.rs#L42

jofas · July 9, 2025, 9:25pm

I'm still not sure what the actual erroneous behaviour is. The argument string looks fine according to the powershell docs.

drewtato · July 9, 2025, 9:34pm

If you show us the command that works in bash, we can show you the equivalent in powershell, but the snippet you posted is identical in both so there's probably something else going on.

system · October 7, 2025, 9:34pm

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Does anyone know how to properly quote a Rust enum as arg in Powershell?

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