docs(installer): correct §5.3's trigger and record what building §5.2 found

Two things this section got wrong, both found by implementing it.

§5.3 said a backup is taken for an update and for an install over an
existing record, because "a first install overwrites nothing". That is
not true of a tree deployed by hand per INSTALL.md Appendix A2 -- the
path this project recommends while the binary is unreleased. There the
first install finds .cs files that differ, plans them as Change, and
overwrites them with no prior record anywhere to notice. The rule is
now the direct one: back up whenever the run is about to overwrite
something. A genuine first install onto a clean tree still writes
nothing, because there is nothing to copy.

Also records that sidecar.toml joins a backup rather than causing one
(nothing rewrites it, so triggering on it would leave a dated directory
after every no-op update), and that the directory is created lazily
with the manifest written last, so an interrupted run can neither be
mistaken for a backup nor evict a good one.

§5.2 gains what its cross-builds turned up: neither crate builds with
the arm64 compiler alone. gcc-aarch64-linux-gnu only recommends
libc6-dev-arm64-cross while both release workflows install with
--no-install-recommends, so the C in each crate -- bundled SQLite under
sqlx, ring under ureq's rustls -- fails on a missing libc header while
every Rust dependency compiles fine.

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
2026-08-05 05:49:09 -05:00
parent 38f83ad2e0
commit e18eec8957

View File

@@ -894,12 +894,13 @@ operators who downloaded a bare binary being told to re-download a package. Defe
costs nothing: nothing is published from `edge`, and the guide's Appendix A is the supported path
meanwhile.
| Item | Decision |
|---|---|
| `.deb` for uo-link | **Dropped** (§5.1) |
| Windows MSI | **Dropped** (§5.1) |
| arm64 cross build | **Build** — Linux `aarch64`, both components (§5.2) |
| Backup before upgrade | **Build** — on by default, scoped to what a run overwrites (§5.3) |
| Item | Decision | State |
|---|---|---|
| `.deb` for uo-link | **Dropped** (§5.1) | — |
| Windows MSI | **Dropped** (§5.1) | — |
| arm64 cross build | **Build** — Linux `aarch64`, both components (§5.2) | In review: [installer#9](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/9), [link#26](https://gitea.whitlocktech.com/RunicGateway/link/pulls/26), [installer#10](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/10); step 3 waits on link's first arm64 release |
| Backup before upgrade | **Build** — on by default, scoped to what a run overwrites (§5.3) | In review: [installer#11](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/11) |
| Docs the release invalidates | **Do** (§5.4) | Pending |
#### 5.1 What ships is plain binaries: no `.deb`, no MSI
@@ -961,6 +962,13 @@ lasts. Hence:
`bundle.yml` is therefore edited on `main` only and never on `edge`, so the cutover merge has nothing
to conflict over.
**What building it found.** Neither crate cross-compiles with the arm64 *compiler* alone.
`gcc-aarch64-linux-gnu` only **recommends** `libc6-dev-arm64-cross`, and both release workflows
install with `--no-install-recommends` — so the C that each crate pulls in (bundled SQLite under
`sqlx` for the sidecar, `ring` under `ureq`'s rustls for the installer) dies on a missing
`bits/libc-header-start.h` while every Rust dependency builds fine. Both halves were reproduced in a
`rust:1-slim-bookworm` container, failure then fix, before either workflow was written.
#### 5.3 Backup before overwrite
**Scoped by what cannot be fetched again.** Not the sidecar binary or the overlay files — both are
@@ -982,14 +990,28 @@ that is still downloadable, and the noise would bury the two files that matter.
from, beside a `manifest.json` naming the source path, its SHA256, and the bundle moved from and
to. In the state directory, not the ServUO tree — the same rule the tier's `patches/originals/`
follows, and for the same reason: `uninstall` has promised never to clean up in there.
- **When:** on by default for `update`, and for an `install` over an existing record. A first
install overwrites nothing and writes no backup. `--verify` writes none either, for the reason it
runs no part of the sidecar half (Phase 2): a dry run must not create state.
- **When: whenever the run is about to overwrite something**, whichever verb was typed. This
section first said "`update`, and `install` over an existing record", justified by a first install
overwriting nothing — **which is wrong**, and building it is what showed that. A tree deployed by
hand per [`INSTALL.md`](INSTALL.md) Appendix A2 — the path this project recommends while the
binary is unreleased — has `.cs` files the first `install` plans as `Change` and overwrites, with
no prior record anywhere to notice. The direct test covers that case, and a genuine first install
onto a clean tree still writes nothing, because there is nothing to copy. `--verify` writes none
either, for the reason it runs no part of the sidecar half (Phase 2): a dry run must not create
state.
- **`sidecar.toml` joins a backup that is already being taken; it is never the reason for one.**
Nothing in the installer rewrites it, so treating it as a trigger would leave a dated directory
behind after every no-op `update` — the empty-backup problem one step along. It is copied so that
a restored set of files arrives with the token that matches it.
- **`--no-backup`** opts out, for an operator with their own snapshotting.
- **Retention is three.** Older ones are pruned as new ones are written; an unbounded directory of
ServUO source copies on a shard host is its own support problem. `uninstall` keeps them and
`--purge` drops them, alongside the config, the database and the cached patch set — same rule as
Phase 4, and the same reason: they are the only offline record of what was there before.
- **The directory is created lazily and the manifest is written last**, so a directory carrying one
is a *complete* backup. Listing and pruning consider only those: a run interrupted mid-copy must
neither be mistaken for a backup nor be able to evict a good one by being newer than it. It is
left on disk for a human to look at rather than silently deleted.
- **Restore is printed, not done.** Consistent with the uninstall report, and for the identical
reason: the installer cannot know what has changed since, and a clever automatic restore over a
newer overlay eats work rather than saving it. `doctor` names the most recent backup and its