Fix empty has_many associations incorrectly returning true

[vincentvanbush]

Description

Fixes #52

This PR fixes the issue where empty has_many associations incorrectly return true in permission checks due to Enum.all?([]) returning true (vacuous truth).

Changes

Core Fix

• File: lib/permit/permissions/parsed_condition.ex:117
• Changed Enum.all? to Enum.any? in check_association/3 function
• Implements "AT LEAST ONE" (existential) semantics for has_many associations

Test Updates

• File: test/permit/permissions/condition_test.exs
• Added test case demonstrating the empty association bug
• Updated existing test to reflect new "ANY" semantics
• Added test for when no record matches all conditions simultaneously
• Renamed test to better describe "ANY semantics" behavior

Behavior Change

Before (Incorrect):

%Movie{actors: []} # Empty list
# Enum.all?([], fn -> ... end) -> true

After (Correct):

%Movie{actors: []} # Empty list
# Enum.any?([], fn -> ... end) -> false

Impact

This change ensures that:

• ✓ Empty associations correctly return false
• ✓ At least one matching record returns true
• ✓ Permission rules behave consistently with Ecto query behavior

Test Results

• ✓ All 56 tests pass in base permit library
• ✓ All 27 tests pass in permit_ecto (including the originally failing test from PR Issue 16/functions query #22)

Related

• Related to Add a failing test for empty associations issue permit_ecto#22
• Discovered through inconsistency between Ecto query behavior and permission checks

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
lib/permit/permissions/parsed_condition.ex	71.42% <100.00%> (ø)

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