[Bug] priority_policy_explicit does not respect priority

[paul4156]

Describe the bug
priority_policy_explicit is still positional, not respecting priority.

To Reproduce
Steps to reproduce the behavior:

1. Use nodejs
2. Use example files for explicit priority: examples/priority_model_explicit.conf and examples/priority_policy_explicit.csv
3. Run script:

const { newEnforcer } = require('casbin');

newEnforcer(
  `${__dirname}/priority_model_explicit.conf`,
  `${__dirname}/priority_policy_explicit.csv`
)
  .then(enforcer => enforcer.enforce('bob', 'data2', 'read'))
  .then(console.log);

3. Got true
4. Swap line 1-4 and line 7-9 in priority_policy_explicit.csv:

p, 1, alice, data1, write, allow
p, 1, alice, data1, read, allow
p, 1, bob, data2, read, deny

p, 10, data1_deny_group, data1, read, deny
p, 10, data1_deny_group, data1, write, deny
p, 10, data2_allow_group, data2, read, allow
p, 10, data2_allow_group, data2, write, allow

g, bob, data2_allow_group
g, alice, data1_deny_group

5. Run the script again
6. Got false

Expected behavior
The priority based policy should work regardless of the order of adding policies and be consistent to true ("allow"), due to bob is in data2_allow_group which has a higher priority.

Screenshots

Desktop (please complete the following information):

• OS: macOS Big Sur 11.2.3
• Browser: nodejs
• Version: node v12.21.0

Additional context
None

[hsluoyz]

@Zxilly

[Zxilly]

working on this

[Zxilly]

Currently pycasbin didn't supoort explicit priority enforce. I'll implement it.