Consolidate evaluate_rapidsmpf into evaluate_streaming in cudf_polars

[mroeschke]

Description

• Address the follow up review Make RapidsMPF the default runtime for cudf_polars streaming executor #22281 (comment)

In a followup we should merge evaluate_rapidsmpf and evaluate_streaming...

• Removes a temporary iterable in select that I had from a leftover branch
• Removes the devcontainers key in dependencies.yml that was leftover from troubleshooting the devcontainer CI job

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR inlines RapidsMPF logical-plan evaluation into evaluate_streaming, removes the evaluate_rapidsmpf wrapper, simplifies temporary name generation in select by consuming the names iterator inline, and deletes the files.devcontainers section from dependencies.yaml.

Changes

Code Simplification

Layer / File(s)	Summary
Name Generation Simplification python/cudf_polars/cudf_polars/experimental/expressions.py	select builds named_exprs using NamedExpr(next(names), expr) directly in a list comprehension instead of precomputing output_names and zipping with strict=True.
Evaluation Function Inlining python/cudf_polars/cudf_polars/experimental/parallel.py	Removed evaluate_rapidsmpf; evaluate_streaming now imports and calls evaluate_logical_plan(...) and returns its result directly.
Dependencies Group Removal dependencies.yaml	Deleted the files.devcontainers section that specified output: none and a curated includes list for devcontainers.

Estimated Code Review Effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly describes the main change: consolidating evaluate_rapidsmpf into evaluate_streaming in cudf_polars, which matches the primary objective of the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description check	✅ Passed	The PR description clearly relates to the changeset, describing the consolidation of evaluate_rapidsmpf into evaluate_streaming, cleanup of a temporary iterable, and removal of leftover devcontainers configuration.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@python/cudf_polars/cudf_polars/experimental/parallel.py`:
- Around line 125-128: The import of evaluate_logical_plan must be moved into
the evaluate_streaming function and wrapped in a try/except that raises a clear
user-facing ImportError if rapidsmpf is missing; inside evaluate_streaming
(before calling evaluate_logical_plan(ir, config_options,
collect_metadata=False)) call _clear_source_info_cache(), then try to import
from cudf_polars.experimental.rapidsmpf.core; on ImportError raise a message
like "The streaming executor requires the 'rapidsmpf' package. Install it or
choose a different executor." and otherwise call evaluate_logical_plan and
return its result.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: 3caedbaf-0d3a-4363-9233-88f2968a792d

📥 Commits

Reviewing files that changed from the base of the PR and between 64a3109 and a5fadc1.

📒 Files selected for processing (2)

• python/cudf_polars/cudf_polars/experimental/expressions.py
• python/cudf_polars/cudf_polars/experimental/parallel.py

[mroeschke]

/merge