How does Buildmaster determine which files have changed?

We are deploying a site to a linux server. The build yesterday took several hours to deploy, I made a change to 1 file in the repo and re-deployed this morning. How is it that it detects 15,733 files have changed instead of just the 1? is it looking at the modified timestamp on the file, file size? if the time or timezone is different on the destination server, will it re-deploy all?

Loading file from C:\Build\Artifacts\1025\1.0\3\1026\site.zip...

Getting list of files in target path...

Getting list of files in artifact...

Determining which files need to be deployed...

15733 files in artifact; 15733 files have changed

Deploying files...

Product: BuildMaster
Version: 4.6.1

The size and last modified/write date are used to determine if a file changed, but in pre-4.9 versions, the local time the server creating the artifact is used in the zip file (instead of UTC), which meant the deployed timestamp could be wrong.

That said, it wouldn't cause a full redeploy... only an incorrect timezone. So, let us know if you see behavior like this (or can repro it with a smaller, less important deployment). It's possible the SSH library we're using handles returning dates differently, and there's an edge case we need to address.