Bug: 'target' can't be a deploy directory anymore

[mainej]

I have a project that compiles into the target directory, a sub-directory of my repo. My site is configured to use target as the 'deploy' directory (aka the 'publish' directory, I think.) This was working until recently.

Recent changes to this netlify/build-image mean that it assumes every project is a rust project, regardless of whether the project uses rust, and that therefore target is cache-able. You can see this by git blameing the following line:

build-image/run-build-functions.sh

Line 678 in 53b83b6

cache_cwd_directory "target" "rust compile output"

After my build finishes (successfully), the caching code mvs the target directory. See this line:

build-image/run-build-functions.sh

Line 746 in 53b83b6

mv $src $dst

Because of this, the /opt/buildhome/repo/target directory doesn't exist when the deploy starts, and the build fails with the log message "Failed during stage 'building site': Deploy directory 'target' does not exist".

I can think of a few fixes:

1. The build functions could check whether the project uses rust before trying to cache the target directory.
2. The build could run the deploy before starting the caching.
3. The caching code could cp the cacheable directories, instead of mving them.
4. The Support Guide could document forbidden deploy directories.

In the meantime, I'll try to compile to a different directory.

I was able to debug this using the docker image. My prior attempts to fix the problem are documented in this support ticket.

[mainej]

Confirmed: after changing the build (aka publish) directory from target to release, my site deployed successfully.

[changke]

Can confirm. The directory name "target" is kind of "reserved".