[robobun]

Question for a maintainer: may --analyze install when a file has a link error that bun also reports at run time (a missing export)? This PR says yes. Notes prices both answers.

Problem

• bun install --analyze src/index.ts exits 1 in a bun init --react project: error: No matching export in "src/index.html" for import "default".
• generate_from_cli (src/bundler/bundle_v2.rs:4522) links the scan as a browser bundle before get_all_dependencies reads the import records. --analyze reads nothing else.

Fix

• A scanner declares what it reads. ImportRecords (--analyze) gets its callback after find_reachable_files, with no link. LinkedExports (bun create <component>) is unchanged.
• Verified: test/cli/install/bun-add.test.ts (17 new cases, 8 fail on main) and bun-link.test.ts.
• Self-reviewed: 13 concerns raised, 9 addressed. 4 concern a second parse pass that left this PR (Notes).

Background

• --analyze bundles the given files with every package external, then installs the packages that the import records name.
• A browser bundle has no default export for an HTML page, so its link fails. The runtime gives that import an HTMLBundle.
• Considered the link kept with only that import accepted: a require() of a top-level-await file still stops the install.

Downsides

• No link error stops --analyze now. bun itself rejects 3 of the 8 probed programs, and a page with such an error does not build.
• A default-imported page now reaches two older scan faults: <img src="images/photo.webp"> adds the npm package images, and a browser map selects the browser file's packages.
• --analyze still skips the files behind an unused re-export of a "sideEffects": false barrel.

Notes

The question, with both options priced

--analyze came with #17035 for #4133, which asks to "generate a package.json and lockfile from a script". The scan already accepts what the runtime rejects: the row "leaves out builtins, paths and aliases" of #45307 pins exit 0 for import "./missing/file", and main installs for import { nope } from "./a.cjs" or for a re-export of a TypeScript interface without type, which bun rejects when it loads the file. The link is not a check of what bun runs.

• Yes (this PR). --analyze does not link. Lost: every link error and link warning of the scan. Among the rows below, bun rejects 3 of 8 programs when it loads them. A link error in the script of a page also no longer stops the install, and that page does not build (bun build ./page.html exits 1).
• No. Keep the link and accept only a default import of an HTML file in the NoMatch arm of match_import_with_export (src/bundler/LinkerContext.rs). That is a change of about the same size, and it was not built. It should fix the three bun init --react* templates. It keeps exit 1 for require() of a file with top-level await, for CSS composes of a missing class and for a CSS @import of a .ts file, which bun runs.
• A second question for the "yes" case: may --analyze exit 0 when a page that it walks has a link error? The row "an import of a missing name in the script of an HTML page" pins exit 0.

#46281 pins exit 1 for two link errors of --analyze. Whichever of the two PRs lands second has to change those rows.

How it was found

• No GitHub issue reports it. A fuzz run on bundler: turn automatic barrel mode off for --ignore-dce-annotations and for the bun test --changed scan #45938 found it: that PR turned the barrel pass off for the dependency scan, and a file behind an unused re-export then reached the link. bundler: turn automatic barrel mode off for --ignore-dce-annotations and for the bun test --changed scan #45938 no longer touches the dependency scan.
• The fault does not need a barrel. Main (5c6d4e2) and 1.4.3 exit 1 on import page from "./page.html", which is line 2 of src/index.ts in all three bun init --react* templates.

Reproduction on main (5c6d4e2)

echo '{ "name": "app" }' > package.json
mkdir src
printf '%s\n' 'import index from "./index.html";' 'import isNumber from "is-number";' 'Bun.serve({ port: 0, routes: { "/*": index } });' 'console.log(typeof isNumber);' > src/index.ts
echo '<!doctype html><script type="module" src="./frontend.tsx"></script>' > src/index.html
echo 'console.log("frontend");' > src/frontend.tsx
bun install --analyze src/index.ts

• main: exit 1, error: No matching export in "src/index.html" for import "default", nothing installed.
• This branch: exit 0, is-number installed.

src/index.ts of every bun init --react* template starts with that import. On a copy of each template (src/runtime/cli/init/react-*) with its dependency lists emptied, main exits 1 with this error and adds nothing. This branch adds react and react-dom to react-app, 3 of the 4 packages of react-tailwind, and 11 of the 12 of react-shadcn. The one it does not add is bun-plugin-tailwind: only bunfig.toml names it ([serve.static] plugins), and the scan does not read bunfig.

What changes, row by row

80 rows: 40 shapes of a file behind export { routes } from "./server", each with and without "sideEffects": false, bun install --analyze, release builds of main 5c6d4e2 and of this branch 40a3dca.

• 72 rows have the same exit code and the same installed package.
• 8 rows go from exit 1 to exit 0. All are errors of the link, in a file that the server side loads:
  • bun runs the program in 5: a default import of an HTML page, export { default } from "./page.html", require() of a file with top-level await, CSS composes of a missing class, a CSS @import of a .ts file.
  • bun also rejects the program in 3: an import of a name that is not exported, an ambiguous export *, a re-export cycle.
• No row goes from exit 0 to exit 1.
• bun create ./App.tsx: 4 rows (a page or a Tailwind file behind an unused re-export, with and without the field) are equal to main. Without the field it still exits 1 on the page import. That is the result of its consumer: the generated project bundles the component for the browser, and bun build ./App.tsx stops at the same error.

Two more rows change because the link no longer stops them. Neither result is right, and both exist on main for other inputs:

• A bare URL in a page. With import page from "./page.html" and <img src="images/photo.webp"> in the page, main exits 1 at the link. This branch exits 0 and adds the npm package images. Main already does that for import * as page from "./page.html", for bun install --analyze page.html, and for url(images/bg.png) in any stylesheet that a script imports. The cause is in HTMLScanner::create_import_record (only an extension of at most 4 bytes is tried as a relative path) and in Resolver::is_external_pattern (with packages = external a bare path is external before the relative rule for CSS URLs). That needs its own fix.
• The browser field. With "browser": { "./impl.ts": "./impl.browser.ts" } the scan follows the browser file. When that file lacks a name that the import asks for, main exits 1 at the link, and this branch installs the packages of the browser file. When the names match, main installs them too. bun loads impl.ts.

Both rows are in bun-add.test.ts as it.failing cases that assert what bun loads. A fix of the scan removes .failing. The fix for the bare URL is separate work, and it should land before or with this PR.

Why not scan_module_graph_from_cli

bun test --changed has a driver that parses and does not link. --analyze does not call it, because it runs through BuildCommand::exec, which sets the options of the scan (packages = external, the entry points, the unresolved-import rule). A call to the other driver needs its own transpiler setup, as ChangedFilesFilter.rs has, and a public collector split out of get_all_dependencies. That is more code than the early return.

Not in this PR: the files behind an unused re-export of a barrel

• A bundle does not parse a re-export of a "sideEffects": false barrel that nothing imports. The runtime loads that file. So --analyze does not install a package that only such a file imports. Main has this miss since barrel optimization shipped (feat(bundler): barrel import optimization — skip parsing unused submodules #26892, 1.3.10).
• A first version of this branch read those files in a second parse pass. It is the commit fb22d3c on the branch robobun/658b944b/analyze-second-pass. It is out because it is a second decision: it changes which files count, and it turns one working install into exit 1: an unguarded import of a package that the registry lacks, behind an unused re-export (main exits 0 and installs the rest).
• The other shape is one line after bundler: turn automatic barrel mode off for --ignore-dce-annotations and for the bun test --changed scan #45938: set its scan_only for the ImportRecords scanner. On a build with that line (bundler: turn automatic barrel mode off for --ignore-dce-annotations and for the bun test --changed scan #45938 at d860b6a), four working installs exit 1: a syntax error, a .node addon, a guarded require and an unguarded import of a package that the registry lacks, each behind an unused re-export.
• A maintainer should pick the shape before either is a PR.

Measurements

Release builds of main 5c6d4e2 and of this branch 40a3dca, same machine.

• Ordinary bun build: +3 instructions per process inside generate_from_cli (472 to 475, qemu-x86_64 -one-insn-per-tb -d exec -dfilter on the function). 0 per file: on_parse_task_complete (18,138 bytes, 1,482 instructions) and resolve_import_records (14,340 bytes, 554 instructions) are equal in both builds.
• Release binary: 107,808,480 to 107,808,480 bytes stripped. Text of bun-profile: 107,662,578 to 107,662,834, +256 bytes (size).
• bun install --analyze calls clone_ast and LinkerContext::link 1 time each on main and 0 times on this branch. bun create ./App.tsx calls each 1 time on both (gdb breakpoint counts).
• Work removed, install --analyze, user instructions, median of 5 runs by turns (perf_event_open):
  • 3,002 files of 3.4 KB: 2,630 M (2,617 to 2,664) to 2,499 M (2,499 to 2,502), peak RSS 433 to 386 MB.
  • 4,200 files: 3,523 M to 3,361 M, 575 to 509 MB.
  • 201 files: 25.2 M to 22.5 M. 4 files: 14.4 M (13.8 to 14.5) to 13.9 M (13.8 to 14.1).

Other open work

• bundler: turn automatic barrel mode off for --ignore-dce-annotations and for the bun test --changed scan #45938 turns the barrel pass off for --ignore-dce-annotations and for the bun test --changed scan. It and this PR do not overlap.
• bundler: run no macro in a bundle made only for its import graph (test --changed, --analyze, bun create <component>) #46281 sets scan_only = fetcher.is_some() in generate_from_cli, which reaches the barrel gate of bundler: turn automatic barrel mode off for --ignore-dce-annotations and for the bun test --changed scan #45938 for both scanners. The first bun create row of this PR fails on a build with that line. Draft bundler: keep a .sqlite import external without the type attribute #45502 sets scan_only only for the --changed scan.
• bun install --analyze: don't exit the process from inside the scan #45323 makes the --analyze callback return instead of exiting.
• The early return follows scan_module_graph_from_cli (Implement bun test --changed #29262) and the bun stats draft feat: add bun stats command for code statistics #22466, which both read the graph with no link.

Where the bun create rows are

test/cli/create/create-jsx.test.ts has tests that install from the public registry, and they fail outside CI. The two bun create rows are in bun-add.test.ts, beside the rows of the scan that they share.

Suites run with the debug build

• test/cli/install/bun-add.test.ts (237 pass) and test/cli/install/bun-link.test.ts (57 pass).

---

no test proof · iteration 0 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/cli/install/bun-add.test.ts

[robobun]

Status: ready for review. PR: #46602

How to reproduce on main (5c6d4e2)

echo '{ "name": "app" }' > package.json
mkdir src
printf '%s\n' 'import index from "./index.html";' 'import isNumber from "is-number";' 'Bun.serve({ port: 0, routes: { "/*": index } });' 'console.log(typeof isNumber);' > src/index.ts
echo '<!doctype html><script type="module" src="./frontend.tsx"></script>' > src/index.html
echo 'console.log("frontend");' > src/frontend.tsx
bun install --analyze src/index.ts

• main and 1.4.3 exit 1 with error: No matching export in "src/index.html" for import "default" and install nothing.
• This branch exits 0 and installs is-number.

src/index.ts of every bun init --react* template starts with that import. A copy of each template with its dependency lists emptied gives the same error on main.

[coderabbitai]

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⚙️ Run configuration

• Source mode: Auto
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• Branch: robobun/658b944b/analyze-reads-imports-before-link
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📥 Commits

Reviewing files that changed from the base of the PR and between 119ae67 and 1c40be9.

📒 Files selected for processing: 1

• test/cli/install/bun-add.test.ts

Walkthrough

The dependency scanner now declares whether it reads import records or linked exports. CLI analysis selects a scan mode and runs the scan at the corresponding point in the build flow. Tests cover dependency analysis across resolution, loading, and registry-error cases.

Changes

Dependency Analysis

Layer / File(s)	Summary
Scanner read modes and result src/bundler/bundle_v2.rs	The scanner stores the analyzer’s read mode. get_all_dependencies returns a BuildResult with no output files or metafiles.
CLI scan mode and timing src/runtime/cli/pm_update_package_json.rs, src/runtime/cli/create_command.rs, src/bundler/bundle_v2.rs	The package update analyzer selects import records, and the create analyzer selects linked exports. The CLI runs import-record scans before copying and linking, and other scans after linking.
Dependency analysis test coverage test/cli/install/bun-add.test.ts	Tests cover analysis with browser-linking and loading errors, syntax and missing-entry errors, absent registry packages, browser-field and HTML image resolution, and bun create scenarios.

Suggested reviewers: jarred-sumner

Priority: ➖ Normal

Merge Risk: 🔵 Low · up to 119ae

The change is mergeable with a bounded test-reliability risk. Replace the fixed registry port so the create test cannot depend on what is listening locally.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly identifies the main change: install --analyze reads import records before linking.
Description check		The description explains the problem, implementation, tradeoffs, testing, and verification results. It does not use the exact template headings, but it provides the required information in equivalent …
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: Description check

Explanation

The description explains the problem, implementation, tradeoffs, testing, and verification results. It does not use the exact template headings, but it provides the required information in equivalent sections.

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[robobun]

^{Updated 10:56 AM PT - Oct 23rd, 2026}

✅ @robobun, your commit 1c40be9c406027c07fddd686119a6436a3316b84 passed in Build #131381! 🎉

---

🧪   To try this PR locally:

bunx bun-pr 46602

That installs a local version of the PR into your bun-46602 executable, so you can run:

bun-46602 --bun

[claude]

Beyond the inline findings, I also checked that the new early return in generate_from_cli does not starve the --analyze path of anything the skipped steps produce: get_all_dependencies reads only record.source_index, record.tag and record.path.text, all set during parse/resolve, and the --analyze callback in pm_update_package_json.rs reads only result.dependencies, never bundle_v2. Both OnDependenciesAnalyze implementors in the tree declare READS, and DependenciesScanner::new is the sole constructor.

Extended reasoning...

The change adds a DependenciesScannerReads discriminant so the --analyze scanner gets its callback right after find_reachable_files, skipping process_files_to_copy, server-component entry points, clone_ast and the link; bun create keeps the linked path. No security-sensitive surface is touched. Human review is still warranted because the PR deliberately widens what --analyze installs (every link error now passes, and the inline findings document two cases where a wrong package set results), and the author explicitly asks a maintainer to decide that policy.

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

[claude]

🔴 Users running bun install --analyze on a project whose default-imported HTML page has a bare asset URL now get a bogus npm package installed instead of an error. The new early return at bundle_v2.rs:4518 skips the link that used to stop such pages, so <img src="images/photo.webp"> reaches get_all_dependencies as the external import images/photo.webp and images is added to package.json and fetched from the registry (pinned by bun-add.test.ts:527). Fix: a bare URL in an HTML page or a CSS url() must never become a package name on the --analyze path, e.g. drop the ext.len() > 4 cut at HTMLScanner.rs:88 or skip records whose importer is an HTML/CSS file in get_all_dependencies. [also at: test/cli/install/bun-add.test.ts:527 - Users of a bun init --react project whose page has <img src="images/photo.webp"> now get an npm package named…]

Why this was flagged

A user has import index from "./index.html" in src/index.ts (what every bun init --react* template generates) and adds <img src="images/photo.webp"> to the page, then runs bun install --analyze src/index.ts. On the base branch generate_from_cli links first and exits 1 with No matching export in "src/index.html" for import "default", so nothing is installed. After this change bundle_v2.rs:4515-4518 returns get_all_dependencies right after find_reachable_files, before linker.link. HTMLScanner::create_import_record at src/bundler/HTMLScanner.rs:81-102 only tries the relative path when the extension is at most 4 bytes, so .webp stays bare; with packages = external the resolver marks it external and get_all_dependencies at bundle_v2.rs:4432 parses images as the package name and inserts it. The PR's own test at test/cli/install/bun-add.test.ts:522-527 asserts added: ["bar", "images"]. No safeguard remains on this path: the registry 404 check only fires if the name does not exist on npm, and images does.

Verification: bundle_v2.rs:4515-4518 returns get_all_dependencies when fetch.reads == ImportRecords, skipping linker.link (4545-4547). HTMLScanner.rs:88 tries a bare path as a relative file only when ext.len() <= 4, so images/photo.webp stays verbatim; resolver.rs:976-979 marks it external and bundle_v2.rs:4426-4442 inserts images. On base, exit 1 and nothing installed; after this change, the unrelated npm package images is installed.

An automated safety screen replaced some characters, such as angle brackets, in the code quoted in this comment with HTML escape codes.

[robobun]

Confirmed, and it is stated under Downsides. Two facts change where the fix has to live:

• Main installs images today without this PR. Measured on main 5c6d4e2: import * as page from "./page.html" with this <img>, bun install --analyze page.html, and a plain import "./styles.css" whose stylesheet has url(images/bg.png) each add images. This PR adds the default import as one more way in.
• Neither suggested change is enough. The extension cut in HTMLScanner only matters for HTML, so CSS url() stays wrong. A filter on HTML or CSS importers in get_all_dependencies drops real packages: the scan finds tailwindcss for the bun init --react=tailwind template through @import "tailwindcss" in its CSS.

The fault is how URL records resolve under packages = external: a bare path is external before any file beside the importer is tried. That fix is separate work and is in progress. 119ae67 turns the case into an it.failing that asserts ["bar"], so the fix removes .failing. The description now says that the fix should land before or with this PR. I leave this thread open for a maintainer to decide the order.

[coderabbitai]

Actionable comments posted: 1

---

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Inline comments:
Review comments at @test/cli/install/bun-add.test.ts:
- Line 589: Update the create fixture’s registry setup to use a server bound
with `port: 0` that returns 404 for every request, and set `BUN_CONFIG_REGISTRY`
to that server’s assigned port instead of hardcoding port 1.

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---

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• Source mode: Auto
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📥 Commits

Reviewing files that changed from the base of the PR and between 5c6d4e2 and 119ae67.

📒 Files selected for processing: 4

• src/bundler/bundle_v2.rs
• src/runtime/cli/create_command.rs
• src/runtime/cli/pm_update_package_json.rs
• test/cli/install/bun-add.test.ts

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[claude]

The follow-up commit (119ae67) moves the browser-field and bare-URL rows to it.failing with the wanted result, which addresses the earlier point about pinning the defect. Beyond the inline nit, I also checked the new early return in generate_from_cli: it runs after reachable_files_count is written, and the --analyze callback reads only result.dependencies (built from import records populated during parse), so the skipped copy/server-component/link steps feed nothing it uses; READS is a trait const with no default, so both scanner impls are forced to declare it.

Extended reasoning...

Since the prior review the only new commit is test-only and flips two tests that pinned known-wrong scan output to it.failing with the runtime-correct expectation; the Rust change in bundle_v2.rs, create_command.rs and pm_update_package_json.rs is unchanged. The ImportRecords early return skips steps whose outputs the --analyze Analyzer never reads, and the compiler enforces the new const on both OnDependenciesAnalyze impls. The remaining open question — whether --analyze may install past a link error that bun also reports at run time — is a product decision the PR itself asks a maintainer to settle, so a human look is still needed.

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

Still open from earlier reviews (1):

• 🔴 src/bundler/bundle_v2.rs:4518 — Users running bun install --analyze on a project whose default-imported HTML page has a bare asset URL now get a bogus…

If you have decided not to act on one of these findings, resolve its thread (a reply alone leaves it open) and the next review stops counting it. To review this commit again now, use Re-run on its "Claude Code Review" check.

[claude]

I reviewed the latest push (through 1c40be9) and found no new bugs; the test follow-ups since my last pass cover what I had raised, and the one decision left is the product question the description already poses — whether --analyze may install past every link error — which needs a maintainer's call rather than more automated review.

What was reviewed:

• The new early return in generate_from_cli: get_all_dependencies reads only record.source_index / record.tag, which are set at parse and resolve time, so skipping process_files_to_copy, server-component boundaries and the link does not change what it sees; the LinkedExports path for bun create is unchanged.
• Both OnDependenciesAnalyze implementors declare READS, and the DependenciesScanner::new copy is the only constructor, so the enum has no unaudited consumer.
• The ASAN_OPTIONS=detect_leaks=0 in the bun create helper matches the existing pattern in test/cli/create/create-jsx.test.ts:440 for the same command; the test rows now assert exit code and use a port: 0 registry.

Extended reasoning...

The change adds a DependenciesScannerReads enum and an early return in src/bundler/bundle_v2.rs so bun install/add --analyze collects import records right after find_reachable_files without linking, while bun create <component> keeps the linked path; the two Analyzer impls and test/cli/install/bun-add.test.ts are the only other files touched. No security-sensitive surface is involved. The Rust change is small and behavior-preserving for the data get_all_dependencies reads, and commits 119ae67 and 1c40be9 addressed the earlier test findings (wanted result under it.failing, exit code asserted, port: 0 registry). It is not approved because the PR deliberately drops every link error from the --analyze scan, which the author flags as a maintainer decision and which conflicts with rows pinned by another open PR, and my earlier inline thread at bundle_v2.rs:4518 about the bare-URL scanner fault remains open.

Still open from earlier reviews (1):

• 🔴 src/bundler/bundle_v2.rs:4518 — Users running bun install --analyze on a project whose default-imported HTML page has a bare asset URL now get a bogus…

If you have decided not to act on one of these findings, resolve its thread (a reply alone leaves it open) and the next review stops counting it. To review this commit again now, use Re-run on its "Claude Code Review" check.