fix(deprecated): keep deprecated packages on their named prerelease line

[Martin Hochel (Hotell)]

Problem

Deprecated v9 packages are supposed to live on a named prerelease line (-beta.x / -alpha.x) forever. Two of them silently fell off it:

Package	Was	Published
@fluentui/react-alert	9.0.0-beta.143	9.0.1-0 (2026-08-11), 9.0.2-0 (2026-08-24)
@fluentui/react-infobutton	9.0.0-beta.119	9.0.1-0 (2026-08-24)

Root cause

These packages carry "disallowedChangeTypes": ["major", "minor", "patch"] and have no change files of their own — they are bumped as dependents of react-popover etc., where the default dependentChangeType is patch.

Beachball resolves a disallowed change type by stepping exactly one notch down its ordered list:

SortedChangeTypes = ['none','prerelease','prepatch','patch','preminor','minor','premajor','major']

So patch → prepatch, and:

semver.inc('9.0.0-beta.119', 'prepatch')   -> 9.0.1-0          <- what happened
semver.inc('9.0.0-beta.119', 'prerelease') -> 9.0.0-beta.120   <- what we wanted

prepatch starts a new prerelease line and drops the beta identifier. Beachball's downgrade is prerelease-unaware, but our config is what exposed it — prepatch was left allowed.

It's intermittent: it only fires when some upstream change file carries dependentChangeType: patch. When everything upstream was prerelease, the packages stayed on beta.x. That's why it went unnoticed for two releases.

Knock-on: the release pipeline goes red

tag-react-components.ts derives the dist-tag from prerelease[0]. For 9.0.1-0 that is 0:

npm dist-tag add @fluentui/react-alert@9.0.2-0 0
npm error Tag name must not be a valid SemVer range: 0
failed to tag @fluentui/react-alert@9.0.2-0

That is the succeededWithIssues on "Tag prelease packages with prerelease tag" in build 383600. Net effect — the beta tags are stale:

Package	beta	latest
@fluentui/react-infobutton	9.0.0-beta.119 (stale)	9.0.1-0
@fluentui/react-alert	9.0.0-beta.143 (stale)	9.0.2-0

Fix (three parts)

1. Stop the bug recurring — disallow premajor/preminor/prepatch on all three deprecated packages, so a dependent patch degrades all the way to prerelease:

current  config | patch -> prepatch   | 9.0.1-0
this PR         | patch -> prerelease | 9.0.0-beta.120

@fluentui/react-virtualizer (9.0.0-alpha.115) was the next domino — same config, still intact. Without this it would have gone to 9.0.1-0 on the next dependent bump.

2. Repair the two damaged packages. The old line is unreachable (9.0.0-beta.120 > 9.0.1-0 is false), so they move forward onto a named line that outranks what's published:

Package	npm	this PR	next publish
@fluentui/react-infobutton	9.0.1-0	9.0.1-beta.0	9.0.1-beta.1
@fluentui/react-alert	9.0.2-0	9.0.2-beta.0	9.0.2-beta.1

Both are > the published version, so this is forward progress, and the derived dist-tag becomes beta again. react-components pins these exactly, so its pins are updated to match.

3. Stop a version-shape problem from failing the release. tag-react-components.ts now skips prerelease identifiers that npm would reject, with a warning naming the package, instead of erroring out.

Verification

Simulated a real release against this branch:

react-infobutton   npm:9.0.1-0          -> 9.0.1-beta.1    | tag: beta  OK | >npm: true
react-alert        npm:9.0.2-0          -> 9.0.2-beta.1    | tag: beta  OK | >npm: true
react-virtualizer  npm:9.0.0-alpha.115  -> 9.0.0-alpha.115 | tag: alpha OK
suite: 9.74.8      pins: 9.0.2-beta.1 / 9.0.1-beta.1

The new tagging guard checked against every version shape we publish:

9.0.1-0                        -> tag: 0        SKIP (warn)
9.0.1-1                        -> tag: 1        SKIP (warn)
9.0.1-beta.0                   -> tag: beta     tag it
9.0.0-alpha.115                -> tag: alpha    tag it
0.0.0-nightly-20260825-0407.1  -> tag: nightly… tag it
9.74.5-experimental.…          -> tag: experimental  tag it
9.74.7                         -> stable, skip

No behaviour change for beta, alpha, nightly or experimental tagging.

Not addressed

The already-published 9.0.1-0 / 9.0.2-0 can't be withdrawn. Consumers of @fluentui/react-components are unaffected (exact pins); only someone installing these deprecated packages directly via @beta was seeing a stale version, and the next release fixes that.

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