Adopt prepared values and strict reusable contexts by Tjstretchalot · Pull Request #2 · GeniosAI/python-common-expression-language

Tjstretchalot · 2026-08-13T23:14:44Z

No description provided.

coderabbitai · 2026-08-13T23:15:01Z

📝 Walkthrough

Walkthrough

The release changes CEL evaluation to use immutable prepared values and reusable native contexts. The Rust runtime, Python stubs, CLI, documentation, benchmarks, and tests adopt the stricter API.

Changes

Prepared context API

Layer / File(s)	Summary
API and runtime implementation `src/context.rs`, `src/lib.rs`, `python/cel/cel.pyi`, `python/cel/cli.py`, `Cargo.toml`	Adds `PreparedValue` and `prepare()`. `Context` now uses prepared bindings and required concrete contexts.
Documentation and usage migration `README.md`, `docs/*/.md`, `CHANGELOG.md`	Updates examples and reference material for prepared values, reusable contexts, and removed legacy APIs.
Prepared-context benchmarks `examples/performance/*`	Adds prepared-context measurements and updates compilation and execution metrics.
Runtime test migration `tests/*`	Adds coverage for preparation, context reuse, program reuse, conversion, callbacks, errors, and strict argument validation.

Estimated code review effort: 4 (Complex) | ~60 minutes

Poem

I’m a rabbit with a context to share,
Prepared values tucked with care.
Programs run, snapshots stay,
Old raw mappings hop away.
CEL now follows a clearer track—
One native context, and no looking back. 🐇

coderabbitai

Actionable comments posted: 21

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Inline comments:
In `@docs/contributing.md`:
- Around line 258-260: Update the evaluate function’s Context annotation to
reference the imported cel module, such as cel.Context, or define a local
Context alias before the function so the example can be defined without
NameError.

In `@docs/getting-started/quick-start.md`:
- Line 426: Update the quick-start example around safe_evaluate so its context
defines age with the value 25 before evaluating “age * 2”; use a separate
age_context if the existing context must retain now.

In `@docs/how-to-guides/business-logic-data-transformation.md`:
- Around line 338-349: Update the metric-calculation flow around
context.add_variable and the calculate_metrics loop to build the user context
from both input and normalized data, then refresh the prepared user binding
after each metric result so subsequent expressions see newly calculated fields.
Preserve the existing graceful error behavior by assigning None when evaluation
fails.

In `@docs/how-to-guides/error-handling.md`:
- Around line 162-167: Update both error-handling examples around evaluate to
remove the unreachable later ValueError branch; merge the handling or narrow the
exception categories so ValueError is handled only once while TypeError retains
the intended behavior.

In `@docs/how-to-guides/production-patterns-best-practices.md`:
- Around line 594-605: Update the benchmark setup around the test-case
evaluation to create one prepared context from test_case["context"] before the
warmup loop, then reuse that context for the correctness check, warmup
evaluations, and timed evaluations instead of calling as_context repeatedly.
- Around line 575-584: The benchmark should prepare its execution artifacts once
instead of rebuilding them in every iteration: create the Context via as_context
and compile the expression to a Program before the warmup and timed loops, then
invoke program.execute(context) inside those loops. Remove the unused double
callback or rename it if custom behavior is required, while preserving the
expected result of 14.0.

In `@docs/reference/cel-compliance.md`:
- Line 83: Update the markdown structure in the Comparison Operators section and
the additional flagged locations by adding required blank lines around headings
and fenced code blocks, and correct the ordered-list marker at the list near
line 529 to satisfy MD029’s numbering rule. Preserve all existing documentation
content.

In `@docs/tutorials/extending-cel.md`:
- Around line 112-113: Update the tutorial example and surrounding explanation
around evaluate and as_context to state that dictionaries are adapter input
converted by as_context, not valid public API Context values; instruct callers
to pass the resulting concrete Context to cel.evaluate rather than a dictionary
directly.

In `@docs/tutorials/thinking-in-cel.md`:
- Around line 464-465: Update the result comment beside the evaluate call to
approximately 58.3006, matching the existing assertion and expression; leave the
calculation and assertion unchanged.

In `@docs/tutorials/your-first-integration.md`:
- Around line 79-89: Update the tutorial wording near the example to refer to
adding variables with add_variables() instead of the removed Context.update()
API, keeping it consistent with the shown call and current API.

In `@examples/performance/prepared_context_benchmark.py`:
- Around line 84-90: Update the replace_and_execute benchmark lambda to call
context.add_variable and then program.execute sequentially without using a tuple
expression, preserving both operations and their order while removing
per-iteration tuple allocation.

In `@python/cel/cli.py`:
- Around line 198-200: Update CELEvaluator context initialization to detect
callable values and register them via Context.add_function, while continuing to
pass non-callable values through prepare and add_variable. Add a regression test
that evaluates a callable supplied in the CELEvaluator context.

In `@src/context.rs`:
- Around line 115-117: Update CelContext’s __repr__ to include the counts of
registered variable names and function names instead of always returning the
constant “Context()”. Track those names internally as needed, while preserving
the “Context(” prefix required by existing documentation tests and keeping
registered values opaque.
- Around line 61-113: Update Context::add_function and the Context lifecycle to
support Python GC traversal and clearing of registered callables. Track the
callbacks retained by self.inner in a GC-visible structure, implement
__traverse__ to visit their captured Python objects, and implement __clear__ to
drop both the tracked references and the callbacks held by inner by rebuilding
or replacing it with an empty equivalent.

In `@src/lib.rs`:
- Around line 285-292: The RustyPyType::try_into_value extraction chain must
reject Python integers outside the i64/u64 ranges before attempting the f64
conversion; update src/lib.rs lines 285-292 accordingly. Add boundary assertions
in tests/test_prepare.py lines 35-38 verifying cel.prepare(2**64) and
cel.prepare(-(2**63) - 1) raise ValueError matching “Failed to prepare”.

Apply the same fix in `@tests/test_prepare.py` around lines 35 - 38.
- Around line 359-364: In src/lib.rs lines 359-364, update the
ExecutionError::UnsupportedBinaryOperator handling to match left.type_of() and
right.type_of() structurally against the integer type enum variants, while
retaining formatted type values only for user-facing messages. In src/lib.rs
line 200, make the OptionalValue downcast the primary optional-value check
instead of relying on opaque.runtime_type_name() == "optional_type"; both sites
must remain correct if upstream type names change.
- Line 213: Update the fallback arm of the Value-to-Python conversion match to
return a conversion error instead of formatting unsupported values with
format!("{other:?}") into a Python string. Preserve the existing handling for
supported variants, including optional_type, and ensure unknown or opaque values
fail explicitly.

In `@tests/test_functions.py`:
- Around line 381-388: Construct the CEL context once before the performance
loop in the test around evaluate, then pass that reused context to each
iteration so the “Function call too slow” measurement excludes per-iteration
context construction. Preserve the existing expression and iteration behavior.

In `@tests/test_logical_operators.py`:
- Around line 34-39: Update the logical-operator test around evaluate to assert
that evaluate("!!true") returns True and evaluate("!!false") returns False
instead of printing or commenting out expectations; then repair the evaluator’s
double-negation handling so both assertions pass.

In `@tests/test_prepare.py`:
- Around line 119-124: Add a test alongside
test_unsupported_values_fail_during_prepare that calls add_variable with a raw
Python value and asserts it raises TypeError, covering both a typical object and
callable if appropriate. Use the existing cel context/setup and verify the
prepared-value-only contract without changing production code.

In `@tests/test_upstream_improvements.py`:
- Around line 45-59: Rename test_substring_not_implemented and
test_split_not_implemented to names indicating that substring() and split() are
implemented, respectively. Update the reference comment in test_stdlib.py to use
the new substring test name.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 431ee5ff-1cd9-41b8-b3c9-13a44e0dfaaa

📥 Commits

Reviewing files that changed from the base of the PR and between f0827b1 and e34dfa6.

⛔ Files ignored due to path filters (1)

Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (50)

CHANGELOG.md
Cargo.toml
README.md
docs/contributing.md
docs/cookbook.md
docs/getting-started/installation.md
docs/getting-started/quick-start.md
docs/how-to-guides/access-control-policies.md
docs/how-to-guides/business-logic-data-transformation.md
docs/how-to-guides/cli-recipes.md
docs/how-to-guides/dynamic-query-filters.md
docs/how-to-guides/error-handling.md
docs/how-to-guides/production-patterns-best-practices.md
docs/index.md
docs/reference/cel-compliance.md
docs/reference/cli-reference.md
docs/reference/python-api.md
docs/tutorials/cel-language-basics.md
docs/tutorials/extending-cel.md
docs/tutorials/thinking-in-cel.md
docs/tutorials/your-first-integration.md
examples/performance/compile_execute_benchmark.py
examples/performance/prepared_context_benchmark.py
python/cel/cel.pyi
python/cel/cli.py
src/context.rs
src/lib.rs
tests/conftest.py
tests/test_arithmetic.py
tests/test_basics.py
tests/test_boolean_coercion.py
tests/test_compile.py
tests/test_context.py
tests/test_datetime.py
tests/test_documentation.py
tests/test_dual_mode_comprehensive.py
tests/test_edge_cases.py
tests/test_enhanced_error_handling.py
tests/test_functions.py
tests/test_issue16_string_literal_regression.py
tests/test_logical_operators.py
tests/test_map_function.py
tests/test_optional_values.py
tests/test_parser_errors.py
tests/test_performance_verification.py
tests/test_prepare.py
tests/test_reduce.py
tests/test_stdlib.py
tests/test_types.py
tests/test_upstream_improvements.py

📜 Review details

⚠️ CI failures not shown inline (2)

GitHub Actions: CI / 5_Code Quality & Type Checking.txt: Adopt prepared values and strict reusable contexts

Conclusion: failure

View job details

st 5: Undefined variable
     - undefined_var = 'undefined_variable'
 390 + undefined_var = "undefined_variable"
 391 | success, result, errors = safe_user_expression_eval(undefined_var, context)
 --------------------------------------------------------------------------------
 409 | # ✅ Safe - check existence first
     - safe_expr = '''
 410 + safe_expr = """
 411 |     has(user.profile) &&
 412 |     has(user.profile.settings) &&
 413 |     has(user.profile.settings.theme) &&
 414 |     user.profile.settings.theme == "dark"
     - '''
 415 + """
 416 |
 --------------------------------------------------------------------------------
 421 | # Test both approaches
     - context_complete = {
     -     "user": {
     -         "profile": {
     -             "settings": {"theme": "dark"}
     -         }
     -     }
     - }
 422 + context_complete = {"user": {"profile": {"settings": {"theme": "dark"}}}}
 423 |
 --------------------------------------------------------------------------------
 443 | # ❌ Risky - assumes numeric types
     - risky_expr = 'user.age > 18'
 444 + risky_expr = "user.age > 18"
 445 |
 446 | # ✅ Safe - use numeric conversion with error handling
     - safe_expr = 'has(user.age) && double(user.age) > 18.0'
 447 + safe_expr = "has(user.age) && double(user.age) > 18.0"
 448 |
 449 | # ✅ Alternative - check for common failure case first
     - defensive_expr = 'has(user.age) && user.age != null && user.age > 18'
 450 + defensive_expr = "has(user.age) && user.age != null && user.age > 18"
 451 |
 --------------------------------------------------------------------------------
 466 |
     - def evaluate_with_logging(expression: str, context: Dict[str, Any], operation_id: str = None) -> Any:
 467 +
 468 + def evaluate_with_logging(
 469 +     expression: str, context: Dict[str, Any], operation_id: str = None
 470 + ) -> Any:
 471 |     """Evaluate with comprehensive logging for production debugging."""
 ----------------------------------------...

GitHub Actions: CI / Code Quality & Type Checking: Adopt prepared values and strict reusable contexts

Conclusion: failure

View job details

st 5: Undefined variable
     - undefined_var = 'undefined_variable'
 390 + undefined_var = "undefined_variable"
 391 | success, result, errors = safe_user_expression_eval(undefined_var, context)
 --------------------------------------------------------------------------------
 409 | # ✅ Safe - check existence first
     - safe_expr = '''
 410 + safe_expr = """
 411 |     has(user.profile) &&
 412 |     has(user.profile.settings) &&
 413 |     has(user.profile.settings.theme) &&
 414 |     user.profile.settings.theme == "dark"
     - '''
 415 + """
 416 |
 --------------------------------------------------------------------------------
 421 | # Test both approaches
     - context_complete = {
     -     "user": {
     -         "profile": {
     -             "settings": {"theme": "dark"}
     -         }
     -     }
     - }
 422 + context_complete = {"user": {"profile": {"settings": {"theme": "dark"}}}}
 423 |
 --------------------------------------------------------------------------------
 443 | # ❌ Risky - assumes numeric types
     - risky_expr = 'user.age > 18'
 444 + risky_expr = "user.age > 18"
 445 |
 446 | # ✅ Safe - use numeric conversion with error handling
     - safe_expr = 'has(user.age) && double(user.age) > 18.0'
 447 + safe_expr = "has(user.age) && double(user.age) > 18.0"
 448 |
 449 | # ✅ Alternative - check for common failure case first
     - defensive_expr = 'has(user.age) && user.age != null && user.age > 18'
 450 + defensive_expr = "has(user.age) && user.age != null && user.age > 18"
 451 |
 --------------------------------------------------------------------------------
 466 |
     - def evaluate_with_logging(expression: str, context: Dict[str, Any], operation_id: str = None) -> Any:
 467 +
 468 + def evaluate_with_logging(
 469 +     expression: str, context: Dict[str, Any], operation_id: str = None
 470 + ) -> Any:
 471 |     """Evaluate with comprehensive logging for production debugging."""
 ----------------------------------------...

🧰 Additional context used

🪛 ast-grep (0.45.1)

examples/performance/prepared_context_benchmark.py

[info] 104-104: use jsonify instead of json.dumps for JSON output
Context: json.dumps(report, indent=2, sort_keys=True)
Note: [CWE-116] Improper Encoding or Escaping of Output.

(use-jsonify)

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python/cel/cli.py

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docs/reference/python-api.md

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docs/reference/cel-compliance.md

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docs/index.md

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docs/tutorials/extending-cel.md

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docs/tutorials/thinking-in-cel.md

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docs/how-to-guides/production-patterns-best-practices.md

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python/cel/cli.py

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docs/reference/python-api.md

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docs/reference/cel-compliance.md

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docs/how-to-guides/production-patterns-best-practices.md

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🪛 LanguageTool

CHANGELOG.md

[style] ~13-~13: Three successive sentences begin with the same word. Consider rewording the sentence or use a thesaurus to find a synonym.
Context: ...or one-time Python-to-CEL conversion. - Added direct reusable native contexts; prepar...

(ENGLISH_WORD_REPEAT_BEGINNING_RULE)

🪛 markdownlint-cli2 (0.23.2)

docs/reference/cli-reference.md

[warning] 46-46: Headings should be surrounded by blank lines
Expected: 1; Actual: 0; Below