Change Details

`WFImplementation.js:102` has a defensive guard: ``` lang=js // TODO (T413840): Determine why this happens; it appears to be due // to some of the list resolution short-circuiting code interacting // negatively with list types. if ( !( fullType instanceof WFBase ) ) { return fullType; } ``` The branch is reached in practice but the root cause is undocumented. This is investigation work, not a bug fix; the outcome is either a real fix to the upstream short-circuit or a written invariant explaining why the fallback is correct. TODO: [x] deploy current fix [ ] monitor for another week to see if the offending logs reappears; [ ] if so, continue to diagnose and fix; if not, remove the guarded bit of code and logs Desired behavior/Acceptance criteria - Identify which call path produces a non-WFBase `fullType` here. Likely candidates: typed-list resolution in `WFList`, the Z8K2 resolution path in `WFCodeImpl.evaluate`. - Either fix the producer so this branch is unreachable and remove the guard, or document the invariant in a comment that replaces the TODO. - All existing tests pass; if a real bug is found, add a regression test.

`WFImplementation.js:102` has a defensive guard: ``` lang=js // TODO (T413840): Determine why this happens; it appears to be due // to some of the list resolution short-circuiting code interacting // negatively with list types. if ( !( fullType instanceof WFBase ) ) { return fullType; } ``` The branch is reached in practice but the root cause is undocumented. This is investigation work, not a bug fix; the outcome is either a real fix to the upstream short-circuit or a written invariant explaining why the fallback is correct. TODO: [x] deploy current fix [x] monitor for another week to see if the offending logs reappears; [x] if so, continue to diagnose and fix; if not, remove the guarded bit of code and logs Desired behavior/Acceptance criteria - Identify which call path produces a non-WFBase `fullType` here. Likely candidates: typed-list resolution in `WFList`, the Z8K2 resolution path in `WFCodeImpl.evaluate`. - Either fix the producer so this branch is unreachable and remove the guard, or document the invariant in a comment that replaces the TODO. - All existing tests pass; if a real bug is found, add a regression test.

`WFImplementation.js:102` has a defensive guard: ``` lang=js // TODO (T413840): Determine why this happens; it appears to be due // to some of the list resolution short-circuiting code interacting // negatively with list types. if ( !( fullType instanceof WFBase ) ) { return fullType; } ``` The branch is reached in practice but the root cause is undocumented. This is investigation work, not a bug fix; the outcome is either a real fix to the upstream short-circuit or a written invariant explaining why the fallback is correct. TODO: [x] deploy current fix [ x] monitor for another week to see if the offending logs reappears; [ x] if so, continue to diagnose and fix; if not, remove the guarded bit of code and logs Desired behavior/Acceptance criteria - Identify which call path produces a non-WFBase `fullType` here. Likely candidates: typed-list resolution in `WFList`, the Z8K2 resolution path in `WFCodeImpl.evaluate`. - Either fix the producer so this branch is unreachable and remove the guard, or document the invariant in a comment that replaces the TODO. - All existing tests pass; if a real bug is found, add a regression test.