Resolve Issues with prettytable-rs dependency

[alamb]

Note: migrated from original JIRA: https://issues.apache.org/jira/browse/ARROW-8637

{{prettytable-rs}} is a dependency of Arrow for creating a string for displaying record batches in a tabular form (see [pretty util|https://github.com/apache/arrow/blob/c546eef41e6ab20c4ca29a2d836987959843896f/rust/arrow/src/util/pretty.rs#L24-L25]) The crate, however, has some issues:

 

1.) {{prettytable-rs}} has a dependency on the {{term}} crate. The {{term}} crate is under minimal maintenance, and it is advised to switch to another crate. This will probably pop up in an [informational security advisory|https://rustsec.org/advisories/RUSTSEC-2018-0015] if it's decided one day to audit the crates.

2.) The crate also has a dependency on {{encode-unicode}}. While not problematic in its own right, this crate implements some traits which can bring about confusing type inference issues. For example, after adding the {{prettytable-rs}} dependency in arrow, the following error occurred what attempting to compile the parquet crate:

 

{{let seed_vec: Vec =}}

{{    Standard.sample_iter(&mut rng).take(seed_len).collect();}}

 

{{error[E0282]: type annotations needed}}
{{   --> parquet/src/encodings/rle.rs:833:26}}
{{    |}}
{{833 | Standard.sample_iter(&mut rng).take(seed_len).collect();}}
{{    | ^^^^^^^^^^^ cannot infer type for T}}

 

Any user of the arrow crate would see a similar style of error.

 

There are a few possible ways to resolve this:

 

1.) Hopefully hear from the crate maintainer. There is a [PR open|https://github.com/phsym/prettytable-rs/pull/125] for the encode-unicode issue.

2.) Find a different table-generating crate with less issues.

3.) Fork and fix prettytable-rs.

4.) ???