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feat(homebrew): Homebrew — Homebrew itself as a v2 resource (ENG-3749) - #32
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Ryan Zhu (underthestars-zhy) merged 7 commits intoNov 1, 2026
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The engine never re-reads a fact when an operation ends, so whatever waits on \.commandLineTools.installed (Homebrew, ENG-3749) sat gated for up to 15 minutes after CLT landed. At 60 s a read nearly always comes due during the install and queues on the CLT lock, so the value lands the moment the install ends. A deleted CLT is also repaired within a minute. The cost is a stat and one pkgutil --pkg-info a minute. latestAvailable stays at 15 minutes, and its catalog check at 6 hours. - Tests: the drift tests' "next read" advances are 60 s, so they prove the new interval. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Every Brew (ENG-3738) needs brew, and the v2 engine could install CLT
but not Homebrew. Homebrew(owner:) installs it headlessly, as the root
daemon, even at the login window, and keeps it owned by one account:
CommandLineTools() // required: Homebrew never installs CLT
Homebrew(owner: "ops")
owner is an account's short name, never root, one per Mac. Every brew
runs as it; people run brew by hand with `brew as-brew-user <cmd>`.
- Installs with Homebrew's own install.sh, run as the owner with
NONINTERACTIVE=1. It refuses root, and as the owner needs sudo only to
create the prefix in root's /opt. So the daemon creates /opt/homebrew
and chowns it (and anything a broken install left) to the owner first:
no sudo, no password. The daemon writes /etc/paths.d/homebrew, which
install.sh skips without sudo.
- Homebrew is a Component that declares HomebrewInstall only once
\.commandLineTools.isInstalled reads true. Safe to gate: remove does
nothing. Without CommandLineTools() it waits silently.
- @monitor(\.homebrew.owners) repairs drift. owners lstats the prefix,
Cellar, Caskroom, opt and bin, and each entry directly inside them,
every 60 s, under the lock the rollout installs under. Deleted ([]) →
install again. Wrong or mixed owners (another admin's brew install) →
chown -R -P <owner> /opt/homebrew, nothing downloaded. brew update
changes nothing.
- ensure mirrors CLTInstaller: a lock-free healthy fast path (owners ==
[owner] and brew --version runs as owner), then a locked CLT read that
waits out a CLT install, then the Homebrew lock. Locks never nest.
Unknown owner, root, Intel and a missing CLT throw before touching the
Mac; a re-own or install that didn't take throws, so retries apply.
- UserContext.setting(_:) sets extra environment variables for a child
run as a user.
- CLT docs no longer say Homebrew calls CLTInstaller.ensure.
- Examples/HomebrewEngine reads the owner from
/etc/astrolabe-homebrew-owner: a LaunchDaemon never sees the sudo
environment that installed it.
- Tests: the owners read (sorted, waits out an install, throws on
failure), ensure on a fresh Mac, leftovers, failures, cancellation, bad
inputs, a CLT install in progress, mixed owners, an owner change, a
re-own that didn't take, a brew that won't run, the lock, and the
engine: CLT then Homebrew, no CommandLineTools(), restart, deletion,
another admin's formula, an owner change and drop, CLT deleted, and the
dry run. withCLT moves to Support beside withHomebrew.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
|
Caution Review failedThe pull request is closed. Walkthrough
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| Check name | Status | Explanation | Resolution |
|---|---|---|---|
| Docstring Coverage |  |
Docstring coverage is 24.74% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 97 functions across 16 files. (1 skipped:… | Write docstrings for the functions missing them to satisfy the coverage threshold. |
-
Check name Status Explanation Description Check Check skipped - CodeRabbit’s high-level summary is enabled. Title check The title clearly identifies the main change: adding Homebrew itself as a v2 resource. The scope and feature are specific and concise. Linked Issues check Check skipped because no linked issues were found for this pull request. Out of Scope Changes check Check skipped because no linked issues were found for this pull request.
Full details: Docstring Coverage
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Explanation
Docstring coverage is 24.74% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 97 functions across 16 files. (1 skipped: 1 unsupported.)
- Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts
I’m a rabbit with a root to tend,
I check the owner, then begin.
If tools are ready, brews can grow,
I mend the paths and check the flow.
Each minute brings a watchful ear,
A healthy Homebrew stays right here.
![coderabbitai[bot]](https://avatars.githubusercontent.com/in/347564?s=60&v=4){kind=small}
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Actionable comments posted: 1
- 🪄 Fix CodeRabbit comments on this PR
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Inline comments:
Review comments at @Sources/Astrolabe/BuiltIn/Homebrew/HomebrewSystem.swift:
- Line 93: Update the install-script fetch in the Homebrew rollout to use an
explicit URLRequest with a bounded timeout, then fetch it with
URLSession.shared.data(for:). Ensure the request also has a bounded resource
timeout so a slow stream cannot hold HomebrewContext.lock indefinitely; preserve
the existing response handling.
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📒 Files selected for processing: 17
Examples/HomebrewEngine/HomebrewApp.swiftPackage.swiftREADME.mdSources/Astrolabe/BuiltIn/CommandLineTools/CLTInstaller.swiftSources/Astrolabe/BuiltIn/CommandLineTools/CommandLineTools.swiftSources/Astrolabe/BuiltIn/CommandLineTools/CommandLineToolsFact.swiftSources/Astrolabe/BuiltIn/Homebrew/Homebrew.swiftSources/Astrolabe/BuiltIn/Homebrew/HomebrewFact.swiftSources/Astrolabe/BuiltIn/Homebrew/HomebrewInstaller.swiftSources/Astrolabe/BuiltIn/Homebrew/HomebrewSystem.swiftSources/Astrolabe/Engine/UserContext.swiftTests/AstrolabeTests/CommandLineToolsTests.swiftTests/AstrolabeTests/HomebrewTests.swiftTests/AstrolabeTests/ProcessRunnerTests.swiftTests/AstrolabeTests/ResourceRecordsTests.swiftTests/AstrolabeTests/Support/FakeCLTSystem.swiftTests/AstrolabeTests/Support/FakeHomebrewSystem.swift
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🧰 Additional context used
🪛 ast-grep (0.45.3)
Examples/HomebrewEngine/HomebrewApp.swift
[error] 43-43: A file is read from a path built from runtime/request input via FileManager.contents(atPath:), Data(contentsOf:), or String(contentsOfFile:). An attacker can supply '../' sequences or absolute paths to read files outside the intended directory (path traversal). Validate and canonicalize the path, reject '..' components, and confine reads to an allow-listed base directory (e.g. resolve with URL(fileURLWithPath:relativeTo:) and verify the resolved path is still inside the base) before reading.
Context: String(contentsOfFile: path, encoding: .utf8)
Note: [CWE-22] Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
(path-traversal-file-read-request-input-swift)
🪛 LanguageTool
README.md
[uncategorized] ~43-~43: Did you mean the proper noun “Apple Silicon”?
Context: ...t owns part of it, and isInstalled. > Apple silicon only, as Homebrew is on macOS. Dropping...
(APPLE_PRODUCTS)
🔇 Additional comments: 16
Sources/Astrolabe/BuiltIn/CommandLineTools/CLTInstaller.swift: 1
13-13: LGTM!Also applies to: 29-29
Sources/Astrolabe/BuiltIn/CommandLineTools/CommandLineTools.swift: 1
11-11: LGTM!Also applies to: 71-71
Sources/Astrolabe/BuiltIn/CommandLineTools/CommandLineToolsFact.swift: 1
21-25: LGTM!Tests/AstrolabeTests/Support/FakeCLTSystem.swift: 1
165-177: LGTM!Tests/AstrolabeTests/CommandLineToolsTests.swift: 1
497-498: LGTM!Also applies to: 570-570, 716-726, 749-749, 787-787, 808-808
Sources/Astrolabe/Engine/UserContext.swift: 1
34-35: LGTM!Also applies to: 118-126, 135-143
Tests/AstrolabeTests/ProcessRunnerTests.swift: 1
188-194: LGTM!Tests/AstrolabeTests/Support/FakeHomebrewSystem.swift: 1
1-225: LGTM!Sources/Astrolabe/BuiltIn/Homebrew/Homebrew.swift: 1
1-67: LGTM!Sources/Astrolabe/BuiltIn/Homebrew/HomebrewFact.swift: 1
1-35: LGTM!Sources/Astrolabe/BuiltIn/Homebrew/HomebrewInstaller.swift: 1
1-132: LGTM!Tests/AstrolabeTests/HomebrewTests.swift: 1
1-593: LGTM!Tests/AstrolabeTests/ResourceRecordsTests.swift: 1
21-21: LGTM!Package.swift: 1
73-77: LGTM!Examples/HomebrewEngine/HomebrewApp.swift: 1
1-47: LGTM!README.md: 1
32-44: LGTM!
…3738) v2 could install CLT and Homebrew itself, but not a single formula or cask, and most farm setup is Brew(...). Brew ports v1's Brew onto @resource, @monitor, and the Homebrew facts and lock: CommandLineTools() Homebrew(owner: "ops") Brew("wget") Brew("firefox", type: .cask) Brew("tailscale", version: .atLeast("1.102.0")) - Brew is a Component that declares BrewPackage (astrolabe.brew) once \.homebrew.isInstalled reads true. Gated on isInstalled, never on one owner: remove really uninstalls, and mixed owners (another admin's brew install) would otherwise hide, and uninstall, every package. - The id is brew:<type>:<short name>, so tap-qualifying a name keeps the id and never uninstalls. The hash covers name, type and minimum: a new .atLeast floor upgrades in place. - rollout: check the Mac without the lock (satisfied → no lock, no brew); else under HomebrewContext.lock, check again, resolve the one owner from system.owners(), brew install|upgrade --formula|--cask <name> as the owner, and verify. An uncomparable version throws and never upgrades. [] owners → homebrewMissing; mixed, root or #uid → homebrewNotReady, retried once Homebrew re-owns. - remove: brew uninstall --formula|--cask <short name>, only if it's there. Uses only what the id is built from. - \.homebrew.packages scans Cellar, Caskroom and opt every 60 s with readdir and readlink, no brew and no lock. Throws only on real I/O errors. Each BrewPackage monitors \.homebrew[satisfies:], its own Bool, so a hand-run brew uninstall or a downgrade is undone within a minute. This replaces v1's 15 s loop. - .latest(checkEvery:) is dropped: time passing never changes a hash. A follow-up adds an available fact that body pins into .atLeast. - HomebrewSystem gains packages() and brew(_:as:). BrewVersion is v1's, verbatim. - Examples/BrewEngine reads packages from /etc/astrolabe-brew-packages. - Tests: ids, hashes and the snapshot; the scan on a temp prefix; v1's version cases; check and the subscript; ensure and uninstall over the fake (call order, no lock when satisfied, upgrade, floors, owners, failures, casks, taps, cancellation, one brew at a time); and the engine: CLT then Homebrew then Brew with no failures, no Homebrew(), drift, dropped from body and across a restart, a new floor, tap qualification, mixed owners, a deleted Homebrew, a superseded rollout waiting on the lock, and the dry run. FakeHomebrewSystem keeps one package map and runs brew. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…rift' into ryan/eng-3749-astrolabe-homebrew-itself-as-a-v2-resource
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…e' into ryan/eng-3738-astrolabe-brew-as-a-v2-resource
…-a-v2-resource feat(brew): Brew — Homebrew formulae and casks as a v2 resource (ENG-3738)
Ryan Zhu (underthestars-zhy)
merged commit Nov 1, 2026
bc387e4
into
ryan/eng-3751-astrolabe-monitor-repair-resources-that-drift
1 check failed
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Implements ENG-3749. Stacked on #31 (ENG-3751), which is stacked on #30, #29, #28, #26 and #25 (
next).What
The v2 engine could install CLT (ENG-3739) but not Homebrew, so no v2 app could put a formula on a fresh Mac.
Homebrew(owner:)installs it as the root daemon, with nobody involved, even at the login window, and keeps it owned by one account:owneris one account's short name (whoami), never root, one per Mac. Everybrewruns as it; people run it by hand withbrew as-brew-user <cmd>.Homebrewis aComponentthat declaresHomebrewInstallonly once\.commandLineTools.isInstalledreads true. That's safe becauseremovedoes nothing. WithoutCommandLineTools()it waits silently: the dry run shows nohomebrewid.@Monitor(\.homebrew.owners):[]) → installed again;brew install), or a newownerinbody→chown -R -P <owner> /opt/homebrew, nothing downloaded;brew updatechanges nothing.bodyleaves Homebrew and every formula in place.How it installs:
install.sh, not the.pkgIt uses Homebrew's own
install.sh, run as the owner withNONINTERACTIVE=1.check_run_command_as_rootaborts outside containers./opt/homebrew, because/optis root's.execute_sudotries every command without sudo first./opt/homebrewandchowns it, plus anything a broken install left in it, to the owner. The script then needs no sudo and no password, and sets the group itself (adminfor an administrator, else the owner's own group)./etc/paths.d/homebrew, whichinstall.shskips without sudo.Considered and dropped: the signed
Homebrew.pkgwith/var/tmp/.homebrew_pkg_user.plist. It's notarized, so the team could be pinned before running it, but it needs a root-only, ACL-free owner plist,pkgutilparsing,installer, and a 150 MB download per install. The trade-off:install.shcomes fromHEADover HTTPS and runs unchecked, as the owner rather than root.Changes
BuiltIn/Homebrew/Homebrew.swift: theHomebrewcomponent andHomebrewInstall(astrolabe.homebrew, idhomebrew).owneronly.HomebrewFact.swift:\.homebrew.ownersandisInstalled.ownerslists every account that owns part of Homebrew, sorted and unique;[]withoutbin/brew. An owner with no account reads as#<uid>.lstats the prefix,Cellar,Caskroom,optandbin, and each entry directly inside them. No links are followed and no subprocess runs.HomebrewInstaller.swift:HomebrewContext(task-local, with a lock and aninstallingflag) andensure(owner:), which mirrorsCLTInstaller:owners == [owner]andbrew --versionruns as the owner, it changes nothing and takes no lock.CommandLineToolsReads.installed(), which waits out a CLT install. The two locks never nest.didNotTakeandbrewDoesNotRunmake a failed fix throw, so the retry policy applies.HomebrewSystem.swift: the protocol, andInstallScriptHomebrewas the real implementation.UserContext.setting(_:): sets extra environment variables (NONINTERACTIVE=1) for a child run as a user.installedis read every 60 s instead of 15 min. The engine never re-reads a fact when an operation ends, so Homebrew would otherwise sit gated for up to 15 min after CLT lands. The cost is astatand onepkgutila minute.latestAvailableand the 6 h catalog check are unchanged. The CLT docs no longer say Homebrew callsCLTInstaller.ensure.Examples/HomebrewEnginereads the owner from/etc/astrolabe-homebrew-owner. An environment variable wouldn't work: the LaunchDaemon never sees thesudoenvironment that installed it.Tests
swift teston this Mac: 272 tests. Everything passes exceptstorageClientConcurrentWritesPreserveAllKeys(.helperNotFound), which also fails onmain.HomebrewTests(35), overFakeHomebrewSystemandFakeCLTSystem:owner; the snapshot is{"owner":"ops","owners":["ops"]}, with an unread monitor left out;removemakes no calls.owners:[]without brew; sorted and unique; waits out an install; a failed read throws rather than reading as[].ensure:reownwith no install;brewthat won't run, both throw.ensures together install once; one started mid-install waits, then finds Homebrew healthy; cancelling one that's waiting changes nothing.homebrewundeclared until the nextinstalledread, then one install and exactly one follow-up;CommandLineTools(), never declared;bodyre-owns, and dropping it leaves Homebrew;rollout homebrew@…, and(monitor)on a repair.Also:
withCLTmoved toSupport, besidewithHomebrew; aUserContext.settingtest; andastrolabe.homebrewinResourceRecordsTests.Open questions
chown -Rover a prefix the owner can write. A non-admin owner could plant a hard link to a root-owned file inside the prefix, and a re-own would hand that file to them. An admin owner gains nothing they don't already have. Options:install.shandbrew updatewrite to~/Library/Caches/Homebrew.Not yet verified
The fakes can't prove these. Run them on a farm Mac or a clean Apple-silicon VM, at the login window with nobody logged in (see
Examples/HomebrewEngine):--dry-run:rollout commandLineTools@…, and nohomebrewuntil CLT exists.ls -ld /opt/homebrewshows the owner,sudo -u <owner> /opt/homebrew/bin/brew --versionworks, andinstall.shnever asks for a password.brew install jqas another administrator:Cellar/jqis the owner's again within about a minute.sudo rm -rf /opt/homebrew: reinstalled within about a minute.brew --versionworks as the new owner.🤖 Generated with Claude Code
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