Array duality demo

Demonstration of array duality (owned array vs borrowed array) with Go and Rust.

Photo album in Go

Directories golangerr and golangok contain photo album software demonstrating array duality.

What's inside?

golangerr demonstrates data corruption caused by not paying attention to array borrowing.

golangok is fixed version.

Notice, how GetHolidayPhotos is implemented in golangerr/album.go and golangok/album.go:

diff -U 15 golangerr/album.go golangok/album.go

Running tests

You can run passing tests in golangerr:

cd golangerr
export GO111MODULE=off
go test

To run (failing) mutation test revealing the hidden bug:

cd golangerr
export GO111MODULE=off
MUTATION_TEST=1 go test

You can run all tests in fixed version golangok:

cd golangok
export GO111MODULE=off
go test

Photo album in Rust

Directory rust contains ported photo album to Rust.

What's inside?

Example shows how explicit distinction between Vec<Photo> and &[Photo] made it impossible to reproduce the bug from first version.

Notice, how get_holiday_photos is implemented in rust/src/album.rs.

Running tests

cd rust
cargo test

Exercise

Optional exercise if you have time to spare.

Add to GetHolidayPhotos boolean arguments june and december. Return photos only for requested months.

If only one month is requested, do not perform copy of any array, this way avoiding unnecessary allocation on the heap.

Do exercise for golangok and rust.