Compilation errors when disabling default features in datafusion-common

[jonmmease]

Describe the bug

When depending on datafusion-common with default-features = false, there are compilation errors related to parquet functionality.

To Reproduce

In the datafusion-expr crate, add default-features = false to the datafusion-common dependency. Then try to build the datafusion-expr crate.

There are compilation errors such as:

error[E0433]: failed to resolve: use of undeclared crate or module `parquet`
  --> datafusion/common/src/file_options/parse_utils.rs:20:5
   |
20 | use parquet::{
   |     ^^^^^^^ use of undeclared crate or module `parquet`

error[E0433]: failed to resolve: use of undeclared crate or module `parquet`
  --> datafusion/common/src/file_options/parquet_writer.rs:20:5
   |
20 | use parquet::file::properties::{WriterProperties, WriterPropertiesBuilder};
   |     ^^^^^^^ use of undeclared crate or module `parquet`

error[E0433]: failed to resolve: use of undeclared crate or module `parquet`
  --> datafusion/common/src/file_options/parse_utils.rs:43:13
   |
43 | ) -> Result<parquet::basic::Encoding> {
   |             ^^^^^^^ use of undeclared crate or module `parquet`

error[E0433]: failed to resolve: use of undeclared crate or module `parquet`
  --> datafusion/common/src/file_options/parse_utils.rs:46:23
   |
46 |         "plain" => Ok(parquet::basic::Encoding::PLAIN),
   |                       ^^^^^^^ use of undeclared crate or module `parquet`
   |
...

Expected behavior

It would be possible to compile datafusion-common with the default parquet feature disabled.

Additional context

In VegaFusion I compile datafusion-common into WASM, and the parquet crate is not (easily?) compatible with WASM due to some non-rust compression dependencies.

I'll have a PR with suggested fix up shortly

[alamb]

In VegaFusion I compile datafusion-common into WASM, and the parquet crate is not (easily?) compatible with WASM due to some non-rust compression dependencies.

@jonmmease in order to avoid such errors in the future, perhaps we can encode the usecase into a CI test

Can you share the command / commands you use to compile for wasm (specifically what target)? Here is what we use for sqlparser-rs

https://github.com/sqlparser-rs/sqlparser-rs/blob/7723ea56c5119c7d1a15233c18eb2aaf48b60dc0/.github/workflows/rust.yml#L48-L56

But I

[jonmmease]

That's a good idea. I made a PR in #7633 that adds a minimal wasm library crate that depends on the various DataFusion crates that are currently wasm compatible.