install: treat a registry package's edge to a pruned workspace as unresolved

[robobun]

Problem

• On a pruned checkout, bun install --frozen-lockfile exits 1 with Failed to install 1 package (hoisted: FileNotFound: failed linking dependency/workspace to node_modules for package host) when a registry package depends on the missing workspace. Example: plugin has the peer host@^1, which bun.lock binds to workspace packages/host.
• With --ignore-scripts the isolated linker exits 0, but installs the skipped workspace's dependencies and creates packages/host/node_modules.
• Cause: is_filtered_dependency_or_workspace (src/install/lockfile/Tree.rs:611) drops only the root's edge to a pruned workspace, so plugin -> host still installs it.

Fix

• The edge now behaves as unresolved. A peer or optional dependency (may_stay_unresolved) of a package that is not local loses its link, the install passes, and a note: names the package and the workspace.
• Every other edge keeps the workspace in the plan. Both linkers check it before they change node_modules and stop with error: package "plugin@1.0.0" depends on workspace "host" (packages/host), which is listed in bun.lock but not on disk.
• A linker can take a peer from an ancestor. It skips a peer only when it picks the pruned workspace.
• Verified: test/cli/install/frozen-lockfile-pruned.test.ts (19 new cases, 16 fail on bun 1.4.3-canary.1).

Background

• A pruned checkout here keeps bun.lock as is, but only some workspace folders (a Docker context). --frozen-lockfile skips a workspace with no package.json on disk.
• bun links a version range to a same-named workspace that satisfies it. So a registry package can depend on a workspace.
• A local package (root, workspace, file: folder) has its package.json on disk.
• The lockfile loader accepts an unresolved peer or optional dependency and rejects a required one (Failed to resolve prod dependency).

Notes

For the maintainer: one deliberate change needs a yes. Two installs that exit 0 today now exit 1, both with the isolated linker and --ignore-scripts: a registry package's required dependency on a pruned workspace, and a remaining workspace's catalog: dependency on one. Today they pass only because the one step that notices the missing folder is the read of its package.json for lifecycle scripts. The install then writes a link into the folder that is not on disk, installs the pruned workspace's own dependencies, and creates packages/host/node_modules. That tree works only if a later step copies the folder in (a Docker COPY . . after the install). The new error names the remedy: keep packages/host/package.json in the checkout, and the install exits 0 with a working tree. No flag restores the old exit 0. Release note: "bun install --frozen-lockfile on a pruned checkout now fails with a clear error when an installed package requires a workspace that is not on disk. This includes the isolated linker with --ignore-scripts, which exited 0 before. A Dockerfile that installs before it copies the rest of the repository in (COPY . .) must copy that workspace's package.json before the install."

The rule. An edge to a pruned workspace behaves as if bun.lock did not resolve it. may_stay_unresolved (src/install/lockfile/bun.lock.rs) already says which edges may be unresolved: a peer and an optional dependency. So those lose the link and the install passes. A required dependency may not be unresolved, so the install fails, now with an explicit error before node_modules changes. A local package is the exception: its package.json is on disk in this checkout, and the documented rule is "If a remaining workspace depends on a skipped one, the install fails". So every edge of the root, of a workspace and of a file: folder is reported, whatever its kind. exit_if_survivor_depends_on_missing already reports optional and peer workspace: edges of a workspace.

Scope. This code runs only when bun.lock still lists the workspace. turbo prune rewrites bun.lock and removes the workspace rows, so its output does not reach it. The lockfile loader applies the same split to such a lockfile, which is where the rule comes from.

Output.

note: skipped 1 workspace listed in bun.lock but not on disk: "host"
note: package "plugin@1.0.0" is installed without its link to workspace "host" (packages/host)

note: skipped 1 workspace listed in bun.lock but not on disk: "host"
error: package "plugin@1.0.0" depends on workspace "host" (packages/host), which is listed in bun.lock but not on disk
note: a pruned checkout must keep the package.json of each workspace that an installed package depends on

The last note is the existing pruned checkout note, reworded so that it covers a registry dependent and names the file to keep. The existing survivor errors print it too. --silent prints none of these lines.

Behavior, released bun 1.4.3-canary.1 against this branch, both linkers, loopback registry.

Case	Before	After
registry package with a peer, an optional peer or an optional dependency bound to the pruned workspace	exit 1, Failed to install 1 package	exit 0, no link, one note:
the same with --ignore-scripts, isolated	exit 0, a host link into the folder that is not on disk, the workspace's own dependencies installed, packages/host/node_modules created	exit 0, none of these, one note:
registry package with a required dependency bound to the pruned workspace	exit 1, Failed to install 1 package, node_modules partly written	exit 1, explicit error, nothing written
the same with --ignore-scripts, isolated	exit 0, see the first note	exit 1, explicit error (deliberate change)
a remaining workspace with "host": "catalog:" where the catalog range links the pruned workspace	exit 1, Failed to install 1 package (isolated with --ignore-scripts: exit 0)	exit 1, workspace "app" depends on workspace "host" ...
a file: folder whose range links the pruned workspace, any kind of edge	exit 1, Failed to install 1 package	exit 1, package "tool@tools/tool" depends on workspace "host" ...
the dependent's parent has its own host@2.0.0 (does not satisfy the peer, so bun.lock keeps the workspace binding), hoisted	exit 1 (the workspace nests under the dependent)	exit 0, the dependent resolves the parent's copy, one note:
the same, isolated	exit 0, peer linked to the parent's copy	identical layout, no note: (the linker links the parent's copy on a full checkout too)
--omit=peer, --omit=optional, --production with a dev-only dependent, --filter of another workspace, a registry package that only the pruned workspace installs, --dry-run	exit 0	identical output and layout

One install that passes today keeps its exit code but changes its layout: the isolated --ignore-scripts row for a peer or optional dependency. With a Docker COPY . . after the install, the peer resolved on main and does not resolve now. The new note: says so at install time, and the remedy is the same: keep the workspace's package.json in the checkout.

The check reads each linker's plan (buffers.hoisted_dependencies after Lockfile::filter, the dependencies of each store node after build_store), so --omit, --production, --filter and the package a peer resolves to are already applied. An edge that this install does not place does not fail it. The error names the owner of each placed edge, so it names only a link that the linker would make. When two packages need the same pruned workspace, both linkers place it once and name the first dependent.

A second frozen install on a passing result is a no-op and prints the same notes. bun prune --dry-run reports nothing to prune. The store folder of a dependent that loses a peer link has no peer hash suffix (plugin@1.0.0, not plugin@1.0.0+<hash>), as with --omit=peer.

Why peers are not filtered up front. The isolated linker resolves a peer by walking the dependent's ancestors and uses the lockfile resolution only as the fallback. With an up-front filter the test a peer bound to a pruned workspace still gets the copy its dependent provides fails on the isolated linker (the link to the parent's copy is lost). For the hoisted tree an up-front skip has the same result: when an ancestor provides the name the peer resolves to it at runtime, and otherwise the workspace would be placed.

History of this PR. Version one stopped every case with the explicit error. A review found that the isolated linker with --ignore-scripts exits 0 for a peer today, so that version broke an install that passes. Version two left every edge of a registry package out. The review on this PR pointed out that a required dependency then breaks at runtime with no diagnostic, and that a file: folder is an on-disk declarer like a workspace. Version three follows both points. A last review asked for the note: per link that is left out, for the remedy in the error's note, and for the scope statement above.

Tests. Per linker: a peer (peer-deps-fixed, with and without --ignore-scripts), an optional dependency (a local tarball, because the registry fixtures have none with a range), a required dependency (one-range-dep, with and without --ignore-scripts), the parent-provided peer, a workspace's catalog: edge, and a file: folder's optional dependency. Hoisted only: --silent. The fixture workspace has a dependency of its own (a-dep) so that a test sees whether the skipped workspace was installed. Three cases pass on the released bun by design: the isolated parent-provided peer (it pins the peer design above) and the two --production cases (they pin that an edge this install does not place does not fail it). Seven existing tests assert the reworded note through the survivorNote constant.

Suites run with the debug build: frozen-lockfile-pruned, frozen-lockfile-missing-workspace, bun-prune (242 pass, 1 skip), isolated-install, bun-workspaces, bun-workspaces-self-contained (191 pass).

Also in this diff. prune.rs now uses the same is_pruned_workspace as the linkers. That helper also checks the resolution tag, because a registry package can share the name of a pruned workspace. Every call site in prune.rs already looks only at workspaces, so bun prune does not change.

Landing order. This branch has content conflicts with #43471 (pruned_workspaces.rs and the test file) and with #43405 (pruned_workspaces.rs). The three changes are independent, so any order works. The branch that lands later needs a rebase. #43471 makes a range of the root or of a remaining workspace that links a missing workspace fail in Diff::generate, before any registry request. It lists the catalog: edge as not covered. This PR reports that edge at plan time.

Found, not part of this change.

• --frozen-lockfile --dry-run and --lockfile-only do not run a linker, so they do not report the new error. The docs sentence says so.
• The isolated linker prints no cause when a lifecycle script read fails: on_task_fail has a _ => {} arm that drops TaskError::RunScripts (src/install/isolated_install/Installer.rs:395, produced at :1661). That is why the isolated failure on main is only Failed to install 1 package.

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no test proof · iteration 2 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/cli/install/frozen-lockfile-pruned.test.ts

[robobun]

^{Updated 1:43 AM PT - Sep 20th, 2026}

✅ @robobun, your commit 984113fd9cb9372480347f1b7223236a014e3747 passed in Build #118866! 🎉

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bunx bun-pr 43581

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[robobun]

Status: ready for review. The last push (526fd10) adds a note: for each link that is left out and names the remedy in the error's note. One deliberate change needs a maintainer's yes: see the first paragraph of Notes in the PR body. All review threads are answered.

How I reproduced it (bun 1.4.3-canary.1+367d939d9, Linux x64, both linkers, loopback registry):

1. Root package.json: { "name": "root", "workspaces": ["packages/*"] }.
2. packages/host/package.json: { "name": "host", "version": "1.5.0" }.
3. packages/app/package.json depends on registry package plugin@1.0.0. plugin has peerDependencies: { "host": "^1" }. The registry also has host@1.0.0.
4. Run bun install. bun.lock has "host": ["host@workspace:packages/host"] and no registry host, so the peer of plugin is bound to the workspace.
5. Delete packages/host and node_modules. Run bun install --frozen-lockfile.

Before: exit 1, Failed to install 1 package, and with the hoisted linker FileNotFound: failed linking dependency/workspace to node_modules for package host. With --linker isolated --ignore-scripts: exit 0, but a dangling host link, and for a workspace with dependencies of its own, those dependencies installed and packages/host/node_modules created.

After, for a peer or an optional dependency: exit 0 with note: skipped 1 workspace listed in bun.lock but not on disk: "host" and note: package "plugin@1.0.0" is installed without its link to workspace "host" (packages/host). plugin is installed without the host link, and nothing is created under packages/host.

After, for a required dependency (plugin has dependencies: { "host": "^1" }): exit 1 before node_modules changes, with error: package "plugin@1.0.0" depends on workspace "host" (packages/host), which is listed in bun.lock but not on disk.

The same steps are the new tests in test/cli/install/frozen-lockfile-pruned.test.ts (fixtures peer-deps-fixed and one-range-dep, workspace no-deps@1.5.0).

[coderabbitai]

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Walkthrough

Frozen-lockfile installs now filter, validate, and report links to pruned workspaces across hoisted and isolated installation. Tests and documentation cover dependency types, diagnostics, linker behavior, and peer resolution.

Changes

Pruned workspace link handling

Layer / File(s)	Summary
Pruned workspace filtering src/install/lockfile/pruned_workspaces.rs, src/install/lockfile/Tree.rs, src/install/lockfile/bun.lock.rs	The lockfile utilities identify pruned workspace targets and filter direct and deferred peer dependency links.
Pruned workspace diagnostics and validation src/install/lockfile/pruned_workspaces.rs	Shared diagnostics handle root, workspace, and package dependents. Link-plan validation reports invalid links and skipped placed dependencies while preserving silent-mode behavior.
Installer integration src/install/hoisted_install.rs, src/install/isolated_install.rs, src/install/prune.rs	Hoisted and isolated installers report pruned-workspace links. Isolated installation skips resolved peer dependencies that link to pruned workspaces. The pruning check uses the shared lockfile implementation.
Behavior coverage and documentation test/cli/install/frozen-lockfile-pruned.test.ts, docs/pm/cli/install.mdx	Tests cover linker layouts, dependency types, diagnostics, silent mode, production installs, unchanged installation state, and peer-version fallback. Documentation describes registry package behavior for skipped workspaces.

Priority: ➖ Normal

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the main change: treating registry-package edges to pruned workspaces as unresolved.
Description check	✅ Passed	The description thoroughly explains the problem, fix, behavior changes, scope, and verification. It does not use the template headings exactly, but it provides the required information in equivalent s…

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[claude]

Findings marked 🟡 are optional suggestions and need no follow-up push.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

Beyond the inline finding, I also checked two things in the latest push and ruled them out: the new is_pruned_workspace indexes items_resolution()[pkg_id] without an invalid_package_id guard, but every caller is covered — is_filtered_dependency_or_workspace returns early on pkg_id >= packages.len() before reaching the skip predicate, the Filter builder loop skips invalid_package_id before the second peer check and before pushing to hoisted_dependencies, and store nodes always carry a valid pkg_id. Rewiring prune.rs::is_pruned_workspace to the shared helper adds the ResolutionTag::Workspace check; its callers pass workspace ids or arbitrary package ids, and the only answer that changes is for a non-workspace package sharing a pruned workspace's name, which was previously misclassified as pruned.

Extended reasoning...

The latest commit (5b044e0) reworks exit_if_install_links_missing to walk the edges the linker placed (hoisted_dependencies/resolutions for hoisted, store node dep_id/pkg_id for isolated) and shares is_pruned_workspace and the error formatter between prune.rs and the new check. I traced the two remaining ways the new helper could misbehave: an out-of-range index from an unresolved edge (guarded at Tree.rs:555 and by the invalid_package_id checks at Tree.rs:736/798 before the push into hoisted_dependencies), and the semantic tightening of prune.rs::is_pruned_workspace (every caller at prune.rs:471, 519, 683, 696, 1242, 1435, 1672, 1852 passes package ids where the added tag check only reclassifies a same-named registry package, which is a correction). One inline finding remains on the --dry-run gap, and an earlier open thread of mine on the note: wording is still open; neither is restated here.

[coderabbitai]

Actionable comments posted: 1

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In `@test/cli/install/frozen-lockfile-pruned.test.ts`:
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[claude]

Code review found no issues

No high-confidence issues detected in this change.