feat: make ExpressionHandler::get_evaluator fallible

[cg-cognition]

Fixes #566 . Makes get_evaluator() return DeltaResult<Arc> to properly handle potential errors. This change is intended to support get_evaluator() doing eager validation checking, but doesn't do the validation itself.

What changes are proposed in this pull request?

Here's a comprehensive summary of all changes made:

1. Core Interface Change (lib.rs):

• Modified ExpressionHandler trait to make get_evaluator return DeltaResult<Arc>
• This change makes error handling explicit at the trait level

2. Implementation Changes (arrow_expression.rs):

• Updated ArrowExpressionHandler to return Ok(Arc::new(...))
• Simple change since this implementation can't fail

3. Error Handling Improvements (data_skipping.rs):

• Simplified error handling using ok()? operator
• Made the code more idiomatic while maintaining error propagation
• Applied to select_stats_evaluator, skipping_evaluator, and filter_evaluator

4. Iterator Changes (log_replay.rs):

• Changed to boxed iterator to handle both success and error cases
• Added explicit error handling path using iter::once(Err(e))
• Maintains original behavior while properly propagating errors

5. Call Site Updates:

• Updated all get_evaluator calls to handle Result type
• Modified in transaction.rs, scan/mod.rs, and table_changes/log_replay.rs
• Added proper error propagation using ? operator

How was this change tested?

Tested with cargo test --all-features --all-targets -- --skip read_table_version_hdfs. Had an issue with getting Java setup but that test doesn't seem relevant to the PR. No new tests need to be written since it's a no-op refactor.

This PR affects the following public APIs

Allows get_evaluator to return a Result type, which opens up the possibility to do eager schema validation.

Additional Context

This PR was entirely written by Devin with a little bit of review from me. Happy to address any feedback and get this over the finish line.

Original Run: https://preview.devin.ai/sessions/e839a4e9bcb444b69b99205babdcf1af

[scovich]

Please update the PR description to correctly follow the breaking change template -- our release management scrapes PR descriptions to build the changelog. It looks like the commented-out template was deleted from the PR description, so you'll need to dig it up from some other PR.

[scovich]

Suggested change

	.map_err(|e| {
	warn!("Failed to create stats selector evaluator: {}", e);
	e
	})
	.inspect_err(|e| warn!("Failed to create stats selector evaluator: {e}"))

(more below)

[scovich]

nit: it's very subjective, but in general I find this sort of multi-line, multi-operation Ok (or Some, etc) to be unnecessarily hard to read because of all the nesting. Factoring it out as a value is easier to read (and change later):

let actions = action_iter
      ...
    .filter(...);
Ok(actions)

Wrapping a single function call or struct creation isn't so bad, because conceptually only one thing is happening, e.g. this code above is not particularly difficult to read:

Ok(Arc::new(DefaultExpressionEvaluator {
    ...
}))

Clippy seems to take a similar stance on monadic chains -- it will almost always force newlines between chained function calls, if more than one of the functions takes args or even if the line gets very long (long before the 100-char line limit).

[cg-cognition]

Updated the PR description, not quite sure if I did it right! Let me know after you review.

[scovich]

LGTM except one new type annotation that seems unnecessary?

[codecov]

Codecov Report

Attention: Patch coverage is 66.03774% with 18 lines in your changes missing coverage. Please review.

Project coverage is 83.36%. Comparing base (be1453f) to head (fa7c9ff).

Files with missing lines	Patch %	Lines
kernel/src/scan/data_skipping.rs	70.83%	0 Missing and 7 partials ⚠️
kernel/src/scan/mod.rs	37.50%	1 Missing and 4 partials ⚠️
kernel/src/transaction.rs	0.00%	0 Missing and 2 partials ⚠️
kernel/src/engine/default/mod.rs	0.00%	0 Missing and 1 partial ⚠️
kernel/src/scan/log_replay.rs	90.90%	0 Missing and 1 partial ⚠️
kernel/src/table_changes/log_replay.rs	0.00%	0 Missing and 1 partial ⚠️
kernel/src/table_changes/scan.rs	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #577      +/-   ##
==========================================
- Coverage   83.46%   83.36%   -0.11%     
==========================================
  Files          74       74              
  Lines       16858    16854       -4     
  Branches    16858    16854       -4     
==========================================
- Hits        14071    14050      -21     
- Misses       2129     2130       +1     
- Partials      658      674      +16     

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