Disscussion: Is 'table metadata not loaded yet' reasonable?

[ZENOTME]

I find that the current_table_metadata interface will check self.current_version and return "table metadata not loaded yet" when it's 0.

    pub fn current_table_metadata(&self) -> Result<&types::TableMetadata> {
        if self.current_version == 0 {
            return Err(anyhow!("table metadata not loaded yet"));
        }
        ...
    }

But I find that it will call load automatically in the open or open_with_op. So I guesss the error will occur in this case: self.current_version = metadata.last_updated_ms; // metadata.last_updated_ms = 0
And we hope user to fix this error like this:

let table = Table::open("");
table.current_table_metadata(); // get error
table.load(); // retry load 

But why not directly return error in open when we can't load a valid current version. And we can assert current_version is valid in current_table_metadata. Like

let table = Table::open(""); // Will return error if the metadata.last_updated_ms = 0 

pub fn current_table_metadata(&self) -> Result<&types::TableMetadata> {
    assert(self.current_version != 0)
    ...
}

I think this way is more friendly for user🤔 When it open succeesfully, it can convince that the version is valid. It don't need to check and process error every time in later operation.

[ZENOTME]

How do you think? @Xuanwo @liurenjie1024

[Xuanwo]

Makes sense, let's do this.

[liurenjie1024]

Yeah, I think returning error in open makes more sense.