Add a hint about expected extension in error message in register_csv,…

[cj-zhukov]

Add a hint about expected extension in error message in register_parquet, register_json, register_avro (#14144)

Which issue does this PR close?

Closes #14144.

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[alamb]

Thank you @cj-zhukov -- this looks great and I think a much better experience than returning an empty dataframe

The only thing I think this PR is missing is some tests to ensure we don't accidentally break the feature in the future

I made a proposal here if that is helpful to you

• Add tests for error cj-zhukov/datafusion#1

[comphead]

Hm, what if the folder contains mixed parquet files and some .txt will that error trigger? That would be not very expected behavior

[cj-zhukov]

Thanks for this good point! I checked this. If folder contains mixed format files, that will not error trigger!
I agree that if it failed, it would not be expected behavior. This code helps to prevent this. I found it in _read_type (https://docs.rs/datafusion/latest/src/datafusion/execution/context/mod.rs.html#1261)

  if !file_path.ends_with(extension) && !path.is_collection() {
      return exec_err!(
          "File path '{file_path}' does not match the expected extension '{extension}'"
      );
  }

[alamb]

I pushed a commit to this branch to fix the cargo fmt 🤦

[alamb]

Thank you @cj-zhukov and @comphead

I think this one is good to go now

[cj-zhukov]

@alamb Andrew, my apologies, I haven't noticed your commit for fixing cargo fmt

[alamb]

No worries! That was my bad for making a PR to your branch that I forgot to run cargm fmt. I also merged up again to main to resolve a conflict in this one

[alamb]

We are very close to getting this merged. I expect it iwll be ready to go once CI completes again

[alamb]

Woohoo! Thanks again @cj-zhukov and @comphead