fix(platform): construct NodeCompatibleFileSystemAdapter safely when node:fs constants are absent

[mattboon]

Bug

NodeCompatibleFileSystemAdapter's constructor reads a node:fs constant unconditionally:

const noFollow = hasOwn(options, "noFollow") ? options.noFollow : nodeFsConstants.O_NOFOLLOW;

In a non-Node runtime (e.g. a browser bundle that transitively imports this adapter), nodeFsConstants is undefined, so construction throws:

TypeError: Cannot read properties of undefined (reading 'O_NOFOLLOW')
    at new NodeCompatibleFileSystemAdapter (…/node-filesystem-adapter.js)
    at new DenoFileSystemAdapter (…/deno/filesystem-adapter.js)
    at new DenoAdapter (…/deno/adapter.js)

…which aborts client hydration.

Issue

Surfaced by #3661 (a client-tree route that value-imports a server helper drags the runtime adapter graph into the browser bundle). Whether or not that leak should happen, the adapter constructor should not crash when node:fs constants are unavailable — the code already models this: NodeFileSystemCapabilityOptions.noFollow is documented as "An own undefined value means unavailable."

Reproduction

Against this repo's source via LOCALDEV, pages-server-import-leak/vector-a in mattboon/veryfront-router-testing:

cd pages-server-import-leak
deno run --allow-all <veryfront-code>/cli/main.ts dev --port 3025
# open http://127.0.0.1:3025/vector-a → console shows the O_NOFOLLOW TypeError, hydration aborts

Fix

Optional-chain the constant deref, matching the documented "undefined means unavailable" contract. When absent, noFollow is undefined → canOpenExactSnapshot is false (correct in a browser), and the constructor no longer throws.

-    const noFollow = hasOwn(options, "noFollow") ? options.noFollow : nodeFsConstants.O_NOFOLLOW;
+    const noFollow = hasOwn(options, "noFollow")
+      ? options.noFollow
+      : nodeFsConstants?.O_NOFOLLOW;

Validation

deno test src/platform/adapters/runtime/shared/node-filesystem-adapter.test.ts → 1 passed (37 steps), 0 failed.

Defense-in-depth only: the deeper server→client leak that pulls this adapter into the browser at all is tracked separately in #3661.

Refs #3661.

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility with runtimes where certain filesystem options are unavailable.
  • Prevented initialization errors in environments that do not provide the optional filesystem constant.

[coderabbitai]

Warning

Review limit reached

@mattboon, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 17 minutes

Enable usage-based reviews in Billing to review now. Otherwise, wait until the next included review is available.
You're only billed for reviews past your plan's rate limits ($0.25/file).

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits for each organization. Most developers receive the normal plan review availability.

For paid Pro and Pro+ PR reviews, CodeRabbit uses adaptive limits for sustained high-volume activity. When a developer's recent PR review activity reaches the 95th percentile or higher among CodeRabbit users, additional reviews become available more gradually as earlier reviews age out of the rolling window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 9295e18f-361e-47db-9072-8595b302223c

📥 Commits

Reviewing files that changed from the base of the PR and between fd50d50 and d884bb6.

📒 Files selected for processing (2)

• src/platform/adapters/runtime/shared/node-filesystem-adapter.test.ts
• src/platform/adapters/runtime/shared/node-filesystem-adapter.ts

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 94ac7d8a-c530-416a-a375-42972b0030f8

📥 Commits

Reviewing files that changed from the base of the PR and between 76ef22c and fd50d50.

📒 Files selected for processing (1)

• src/platform/adapters/runtime/shared/node-filesystem-adapter.ts

---

📝 Walkthrough

Walkthrough

The filesystem adapter constructor now treats unavailable nodeFsConstants.O_NOFOLLOW values as unavailable instead of throwing during construction.

Changes

Filesystem capability handling

Layer / File(s)	Summary
Optional O_NOFOLLOW lookup src/platform/adapters/runtime/shared/node-filesystem-adapter.ts	The constructor uses optional chaining when reading nodeFsConstants.O_NOFOLLOW.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Mergeability Score: ⚪ Minimal · up to fd50d

The change prevents adapter construction from crashing in runtimes without node:fs constants while preserving unavailable no-follow behavior; no actionable merge-blocking risk remains after normal checks and review.

Possibly related PRs

• veryfront/veryfront-code#3293: Hardens O_NOFOLLOW handling in the same adapter constructor.
• veryfront/veryfront-code#3380: Adjusts filesystem capability handling for unsupported undefined values.

Suggested reviewers: kwakayama, kojiwakayama

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the constructor fix for runtimes without node:fs constants.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/nodefs-ofollow-browser-safe

---

_{Comment @coderabbitai help to get the list of available commands.}