What is the role of the go.sum file in managing dependencies in a Go project?

The go.sum file is used to ensure the security and integrity of dependencies in a Go project. It contains checksums (hashes) of all modules and their versions used in the project.

When you add or update dependencies, go.sum records their exact versions and hashes. During subsequent builds, Go verifies that the modules being downloaded match these checksums, preventing tampering or corruption of dependencies.

Thus, go.sum helps guarantee that the project always uses verified and unaltered library versions.