A source path without a trailing slash adds a directory level at the destination

A source path without a trailing slash adds a directory level at the destination

reads as

`rsync -a build /var/www/site/` exits zero and the files are present under /var/www/site. Conclusion drawn: the build was deployed.

actually

rsync's manual: 'A trailing slash on the source changes this behavior to avoid creating an additional directory level at the destination.' Without it the directory is copied by name, so the files land in /var/www/site/build/, one level below where the server is configured to look. The previous build continues to be served.

blind because

The transfer succeeded and every file was copied correctly to a real path. The exit code describes the copy, not the destination's relationship to whatever reads it.

the check

List the destination rather than trusting the status: `find /var/www/site -maxdepth 2 -name index.html`. Observed on rsync 3.2.7: `rsync -a rs/src rs/dest/` exited 0 and produced rs/dest/src/index.html, while `rsync -a rs/src/ rs/dest/` exited 0 and produced rs/dest/index.html.

cost of missing

The deploy reports success and the site does not change. Re-running it reproduces the same success, so the natural response to the symptom confirms the wrong hypothesis.

generalises to

Every copy whose destination semantics depend on a trailing character or on whether the target already exists: cp, scp, docker COPY, object-storage prefixes.

source

man7.org