[9.3.0] Fix hang on include() cycles in MODULE.bazel (https://github.com/bazelbuild/bazel/pull/30737)

[bazel-io]

Description

ModuleFileFunction#advanceHorizon compiles the module files named by the current horizon of include() statements and returns their own include() statements as the next horizon, without ever checking whether a file has already been compiled. A cycle among included files thus keeps the horizon non-empty forever, so that ModuleFileFunction spins in an endless loop, re-reading and re-compiling the same files until the build is interrupted. For the same reason, a "diamond" include structure results in a number of compilations that is exponential in the include depth.

This PR skips include labels that have already been compiled (or that appear more than once in the same horizon) when advancing the horizon, which makes the loop terminate, and reports actual cycles as an error when the module file is executed, where the chain of include() calls is readily available:

ERROR: .../MODULE.bazel:1:8: include() cycle detected: //java:java.MODULE.bazel -> //python:python.MODULE.bazel -> //java:java.MODULE.bazel

Note that skipping already-compiled files does not change evaluation semantics: include() behaves as if the included file were textually inserted at the location of the call, and a file reachable via multiple include() paths is still executed once per path. Only the compilation of the file is shared.

Motivation

A single typo in a MODULE.bazel file (e.g. a foo.MODULE.bazel that includes itself) currently makes Bazel spin at 100% CPU with no output and no way to make progress. include() is only allowed in the root module and in modules with a non-registry override, so this is reachable from user-authored files.

Build API Changes

No

Checklist

• I have added tests for the new use cases (if any).
• I have updated the documentation (if applicable).

Release Notes

RELNOTES: Cycles between MODULE.bazel files connected via include() are now reported as an error instead of hanging the build.

Closes #30737.

PiperOrigin-RevId: 967604241
Change-Id: I8c0d8d082338e41c6b83712d452c82ad6da8517a

Commit ce039a7