XO1304: module content does not match xo.lock

xo.lock records the content hash of every module version the build uses (and of the xo.mod of every version minimal version selection read); every build recomputes them from the cache or vendor/ and compares. A mismatch means the code changed under the same version: a tag was moved or rewritten upstream, or a cached or vendored copy was edited. Nothing is built. If the new content is expected (you control the dependency and retagged it), delete its lines from xo.lock and run xo mod tidy; for an edited vendor/, run xo vendor. See core 4.3.

Example

# xo.lock
github.com/acme/billing v1.4.0 h1:AAAA...   # the tag now has other content

Fix

# delete the stale lines, then
xo mod tidy

Run xo explain XO1304 for this text in a terminal, or see section 10.6 of the specification.