fix(tooling): enforce pinned uv in local recipe guards

[acgetchell]

• Reject missing or mismatched uv versions with actionable diagnostics.
• Reuse the canonical version guard across uv-backed validation helpers.

Closes #203

Summary by CodeRabbit

• Bug Fixes

  • Improved validation of the configured uv version.
  • Error messages now identify both the expected and detected versions when validation fails.
  • Standardized tool setup checks for improved reliability.

• Tests

  • Added coverage to verify tool discovery and pinned uv handling.

[coderabbitai]

📝 Walkthrough

Walkthrough

The Justfile centralizes uv checks in _ensure-uv. The guard validates the executable path and configured version. Tool recipes depend on the guard, and regression tests verify dependencies and mismatch output.

Changes

Pinned uv guard

Layer / File(s)	Summary
Implement and wire the uv guard justfile	_ensure-uv resolves uv, checks the configured version, and reports mismatches. Actionlint, shellcheck, shfmt, and yamllint reuse the guard.
Validate recipe metadata and mismatch handling scripts/tests/test_justfile_discoverability.py	Tests verify shared prerequisites, version-check usage, and diagnostics from a mismatched fake uv executable.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related issues

• acgetchell/mcmc-learned-proposals#6 — Covers the same centralized _ensure-uv guard and exact-version validation pattern.
• Enforce the uv pin and reject malformed notebook schema fields causal-triangulations#223 — Modifies _ensure-uv and tool recipes to enforce and reuse a pinned version.

Possibly related PRs

• acgetchell/la-stack#202 — Both PRs modify Justfile tool-version handling and validation.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes enforcing the configured pinned uv version in local recipe guards.
Linked Issues check	✅ Passed	The changes enforce the configured uv version, reuse _ensure-uv across uv-backed helpers, preserve checks, and add focused regression tests for issue #203.
Out of Scope Changes check	✅ Passed	All changes support issue #203 by updating recipe guards and adding focused tests for pinned uv behavior.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/203-uv-version-guard

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.86%. Comparing base (6a3c762) to head (938aff6).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #204   +/-   ##
=======================================
  Coverage   97.86%   97.86%           
=======================================
  Files           8        8           
  Lines        4969     4969           
=======================================
  Hits         4863     4863           
  Misses        106      106           

Flag	Coverage Δ
unittests	97.86% <ø> (ø)

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[coderabbitai]

🧹 Nitpick comments (1)

scripts/tests/test_justfile_discoverability.py (1)

54-70: 🎯 Functional Correctness | 🔵 Trivial | ⚡ Quick win

Add success and missing-executable guard tests.

This test covers only a version mismatch. Add a successful _ensure-uv invocation with the configured uv. Add a PATH fixture without uv and assert the missing diagnostic. This protects both required guard states.

As per coding guidelines, “Test both adversarial inputs and well-conditioned inputs.”

🤖 Prompt for 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.

In `@scripts/tests/test_justfile_discoverability.py` around lines 54 - 70, Extend
the guard tests near test_uv_guard_reports_expected_and_actual_versions with a
success case using the configured uv executable and a missing-executable case
using a PATH fixture that contains no uv. Assert the successful _ensure-uv
invocation exits successfully, and assert the missing case fails with the
expected “missing” diagnostic while preserving the existing mismatch coverage.

Source: Coding guidelines

🤖 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.

Nitpick comments:
In `@scripts/tests/test_justfile_discoverability.py`:
- Around line 54-70: Extend the guard tests near
test_uv_guard_reports_expected_and_actual_versions with a success case using the
configured uv executable and a missing-executable case using a PATH fixture that
contains no uv. Assert the successful _ensure-uv invocation exits successfully,
and assert the missing case fails with the expected “missing” diagnostic while
preserving the existing mismatch coverage.

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ℹ️ Review info

⚙️ Run configuration

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Run ID: 2801db61-28d2-4c83-9036-24b08bf8dca2

📥 Commits

Reviewing files that changed from the base of the PR and between 6a3c762 and 938aff6.

📒 Files selected for processing (2)

• justfile
• scripts/tests/test_justfile_discoverability.py