[Bug] aptos move coverage is incorrectly calculated

[brmataptos]

🐛 Bug

The stats generated by aptos move coverage summary use incorrect covered/unconvered numbers because inlined function line numbers are attributed to the calling module.

The summaries shown by aptos move coverage source likely fail to show inline functions called from tests in other modules.

This will take some effort to sort out.

[brmataptos]

The problem may be more severe than this. The summary view is inconsistent with the source view. In the following listing, summary shows module acl has 0.00 Module coverage, but the source view shows that all lines are covered.
Perhaps the interpretation of covered/uncovered is reversed in the source view.

brm@brms-mbp-2 move-stdlib % aptos move coverage summary                    
+-------------------------+
| Move Coverage Summary   |
+-------------------------+
Module 0000000000000000000000000000000000000000000000000000000000000001::bcs
>>> % Module coverage: NaN
Module 0000000000000000000000000000000000000000000000000000000000000001::fixed_point32
>>> % Module coverage: 100.00
Module 0000000000000000000000000000000000000000000000000000000000000001::hash
>>> % Module coverage: NaN
Module 0000000000000000000000000000000000000000000000000000000000000001::vector
>>> % Module coverage: 99.02
Module 0000000000000000000000000000000000000000000000000000000000000001::error
>>> % Module coverage: 0.00
Module 0000000000000000000000000000000000000000000000000000000000000001::acl
>>> % Module coverage: 0.00
Module 0000000000000000000000000000000000000000000000000000000000000001::bit_vector
>>> % Module coverage: 97.39
Module 0000000000000000000000000000000000000000000000000000000000000001::signer
>>> % Module coverage: 100.00
Module 0000000000000000000000000000000000000000000000000000000000000001::features
>>> % Module coverage: 27.60
Module 0000000000000000000000000000000000000000000000000000000000000001::option
>>> % Module coverage: 94.76
Module 0000000000000000000000000000000000000000000000000000000000000001::string
>>> % Module coverage: 81.82
+-------------------------+
| % Move Coverage: 69.67  |
+-------------------------+
{
  "Result": "Success"
}
brm@brms-mbp-2 move-stdlib % aptos move coverage source --module acl
Code coverage per line of code:
  + indicates the line is not executable or is fully covered during execution
  - indicates the line is executable but NOT fully covered during execution
Source code follows:
+ /// Access control list (acl) module. An acl is a list of account addresses who
+ /// have the access permission to a certain object.
+ /// This module uses a `vector` to represent the list, but can be refactored to
+ /// use a "set" instead when it's available in the language in the future.
+ 
+ module std::acl {
+     use std::vector;
+     use std::error;
+ 
+     /// The ACL already contains the address.
+     const ECONTAIN: u64 = 0;
+     /// The ACL does not contain the address.
+     const ENOT_CONTAIN: u64 = 1;
+ 
+     struct ACL has store, drop, copy {
+         list: vector<address>
+     }
+ 
+     /// Return an empty ACL.
+     public fun empty(): ACL {
+         ACL{ list: vector::empty<address>() }
+     }
+ 
+     /// Add the address to the ACL.
+     public fun add(self: &mut ACL, addr: address) {
+         assert!(!vector::contains(&mut self.list, &addr), error::invalid_argument(ECONTAIN));
+         vector::push_back(&mut self.list, addr);
+     }
+ 
+     /// Remove the address from the ACL.
+     public fun remove(self: &mut ACL, addr: address) {
+         let (found, index) = vector::index_of(&mut self.list, &addr);
+         assert!(found, error::invalid_argument(ENOT_CONTAIN));
+         vector::remove(&mut self.list, index);
+     }
+ 
+     /// Return true iff the ACL contains the address.
+     public fun contains(self: &ACL, addr: address): bool {
+         vector::contains(&self.list, &addr)
+     }
+ 
+     /// assert! that the ACL has the address.
+     public fun assert_contains(self: &ACL, addr: address) {
+         assert!(contains(self, addr), error::invalid_argument(ENOT_CONTAIN));
+     }
+ }
{
  "Result": "Success"
}

[github-actions]

This issue is stale because it has been open 45 days with no activity. Remove the stale label or comment - otherwise this will be closed in 15 days.

[brmataptos]

To reduce effort debugging, note that you can test changes to the coverage code by running the aptos binary built in the current project:

cd aptos-move/framework/move-stdlib
cargo run --locked --profile ci -p aptos --bin aptos -- move test --coverage |& tee move-test-coverage.out
cargo run --locked --profile ci -p aptos --bin aptos -- move coverage source --module acl |& tee move-coverage-source.out

The first build took 21 minutes for me, but after that it is not rebuilt.