fix(app): copy css.d.ts into Docker builder stage

[brandon-pereira]

The production Docker image failed to build after the TypeScript 6 upgrade (#2617) with TS2882: Cannot find module or type declarations for side-effect import of '@mantine/core/styles.css'.

That upgrade added packages/app/css.d.ts (the ambient declare module '*.css' that types side-effect stylesheet imports) and updated the Dockerfile to copy the new mdx.d.ts — but omitted css.d.ts. The builder stage assembles app source from selective COPY statements (src, pages, public, styles, types) that don't include package-root .d.ts files, so css.d.ts never reached the build. Local lint and CI type-checks passed because the file is present there; only the Docker build, with its selective copies, missed it.

Fix: copy css.d.ts into the builder stage alongside mdx.d.ts.

[changeset-bot]

🦋 Changeset detected

Latest commit: 8acc192

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@hyperdx/app	Patch
@hyperdx/api	Patch
@hyperdx/otel-collector	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
hyperdx-oss	Ignored	Preview	Jul 10, 2026 9:04pm
hyperdx-storybook	Ignored	Preview	Jul 10, 2026 9:04pm

[github-actions]

🔴 Tier 4 — Critical

Touches auth, data models, config, tasks, OTel pipeline, ClickHouse, or CI/CD.

Why this tier:

• Critical-path files (1):
  • docker/hyperdx/Dockerfile

Review process: Deep review from a domain expert. Synchronous walkthrough may be required.
SLA: Schedule synchronous review within 2 business days.

Stats

• Production files changed: 1
• Production lines changed: 2
• Branch: brandon/fix-docker-build
• Author: brandon-pereira

To override this classification, remove the review/tier-4 label and apply a different review/tier-* label. Manual overrides are preserved on subsequent pushes.

[greptile-apps]

Greptile Summary

This PR fixes the app Docker production build after the TypeScript upgrade.

• Copies packages/app/css.d.ts into the Docker builder stage.
• Keeps the new CSS ambient declarations beside the existing MDX declaration copy.
• Adds a patch changeset for @hyperdx/app.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
docker/hyperdx/Dockerfile	Copies css.d.ts with the app package-root build files so the Docker builder stage can type-check CSS side-effect imports.
.changeset/docker-copy-css-dts.md	Adds a patch changeset for the app Docker build fix.

_{Reviews (2): Last reviewed commit: "chore: shorten changeset to one line" | Re-trigger Greptile}

[github-actions]

E2E Test Results

✅ All tests passed • 234 passed • 3 skipped • 1578s

Status	Count
✅ Passed	234
❌ Failed	0
⚠️ Flaky	2
⏭️ Skipped	3

Tests ran across 4 shards in parallel.

View full report →

[github-actions]

Deep Review

✅ No critical issues found.

The one-line COPY addition is correct and verified end-to-end: css.d.ts lands at /app/packages/app/css.d.ts in the node_base stage, the builder stage (FROM node_base) inherits it, and next build type-checks it because tsconfig.build.json's include glob **/*.ts matches the package-root declaration file. The ambient declare module '*.css' it provides is what resolves the TS2882 failure. The changeset is well-formed (@hyperdx/app matches packages/app/package.json; patch is valid). No other build-required root-level declaration or config file is missing from the COPY list.

🟡 P2 -- recommended

• docker/hyperdx/Dockerfile:55 -- The production image is built only in release.yml/release-nightly.yml, so drift between this stage's selective package-root COPY list and the files the app build actually needs is never exercised on PRs — which is exactly how this bug reached main.
  • Fix: Add a path-filtered CI step (triggered on changes to docker/hyperdx/Dockerfile or packages/app/*.d.ts) that builds only the builder/type-check stage via docker buildx build --target builder, avoiding a full multi-arch prod build.
  • _{testing, correctness, project-standards}

🔵 P3 nitpicks (1)

• docker/hyperdx/Dockerfile:55 -- Root-level declaration files are enumerated individually on one long space-separated COPY line, so every future packages/app/*.d.ts must be added manually or be silently dropped from the build.
  • Fix: Consider copying a narrower glob (e.g. the app *.d.ts / *.config.* files) so the intent stays self-maintaining; pre-existing pattern, optional.

---

Reviewers (4): correctness, testing, maintainability, project-standards.

Testing gaps: No PR-time guard verifies the production Dockerfile's app COPY list stays in sync with package-root files the build needs; this class of regression surfaces only at release/nightly build time.