Bazel WORKSPACE Deprecated - Bzlmod Migration Errors in CI

Bazel is moving from WORKSPACE to bzlmod (MODULE.bazel). On Bazel 7 bzlmod is on by default and on Bazel 8 WORKSPACE is disabled - so repositories you still declare only in WORKSPACE stop resolving in CI after a Bazel upgrade.

What this error means

After upgrading Bazel, targets fail because external repos defined in WORKSPACE are no longer visible - "repository not found" for deps that bzlmod does not know about. The same checkout built on the older Bazel.

Bazel output

ERROR: no such package '@com_example_lib//':
  The repository '@com_example_lib' could not be resolved:
  No repository visible as '@com_example_lib' from main repository.
  (WORKSPACE is disabled; declare it in MODULE.bazel.)

Common causes

WORKSPACE disabled by default on new Bazel

Bazel 8 disables WORKSPACE loading; repos declared only there are invisible unless re-declared via bzlmod.

Partial bzlmod migration

Some deps moved to MODULE.bazel but others still live in WORKSPACE; with bzlmod on, the WORKSPACE-only ones do not resolve.

How to fix it

Migrate repos to MODULE.bazel

Re-declare external deps as bazel_dep or via a module extension instead of WORKSPACE rules.

MODULE.bazel

# MODULE.bazel
bazel_dep(name = "rules_go", version = "0.48.0")
# for non-registry archives, use http_archive via a module extension
http_archive = use_repo_rule("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
http_archive(name = "com_example_lib", urls = [...], sha256 = "...")

Temporarily re-enable WORKSPACE to unblock

As a bridge during migration, re-enable WORKSPACE resolution while you port deps.

.bazelrc

# .bazelrc (transitional only)
common --enable_workspace

How to prevent it

Migrate all external deps to MODULE.bazel before upgrading to Bazel 8.
Pin the Bazel version in .bazelversion so upgrades are intentional.
Run bazel mod graph to confirm every dep is bzlmod-resolved.