Archive downgrade versus tarball rollback when standard library compatibility is at risk after a Nim upgrade failure

After a failed Nim compiler upgrade, restoring a previous toolchain version requires choosing between two documented recovery paths, each with distinct risk profiles for existing project integrity.

One documented path restores a previous compiler binary from the official archive, leaving installed packages intact, but may mismatch standard library modules with the target version, causing compilation errors for code dependent on recent language features.

Another path replaces the Nim binary from a saved tarball, avoiding package manager side effects and preserving the current package set, yet requires careful PATH management; an improperly ordered PATH can overwrite the active version and introduce unpredictable behavior across unrelated projects.

Given these documented trade-offs, a precise decision is needed to reconcile compiler version consistency with downstream package compatibility after an interrupted upgrade.

• Under what conditions does the archive downgrade path preserve compileability of previously built Nim packages without requiring standard library reindexing?
• When does the tarball rollback path require resetting the package manager cache to restore package consistency, and what PATH safeguards prevent version confusion across projects?
• Is there a documented hybrid workflow that combines archive downgrade with targeted standard library patching to avoid full source rebuilds?