[peterolkhov]

Problem

A blank variant becomes 0 through Number(variant), so getNumberDetails('flag', 42) silently returns zero instead of the caller's default. The Node provider already rejects blank variants; its original PR explicitly left the web equivalent for a follow-up.

Changes

Match the Node guard in the web provider. Empty and whitespace-only variants now produce TYPE_MISMATCH, letting OpenFeature return the caller's default; valid numeric variants, including '0', keep working. Added provider-level cases and regressions through the real OpenFeature client, plus a patch changeset.

Validation on Node 24.13.0:

• Before the guard: 5 new cases failed and 28 passed. Afterward: all 33 package tests passed.
• pnpm turbo run test:unit check-types lint build --filter=@posthog/openfeature-web-provider --concurrency=2 passed, including prerequisite builds.
• Root pnpm format, pnpm lint:oxlint, pnpm lint:playground, changeset status, and git diff --check passed.

The full monorepo build, type-check, and test matrices were not run; dependency installation was limited to the provider's workspace graph and root tools.

Release info Sub-libraries affected

Libraries affected

• All of them
• posthog-js (web)
• posthog-js-lite (web lite)
• posthog-node
• posthog-react-native
• @posthog/react-native-plugin
• @posthog/react
• @posthog/ai
• @posthog/convex
• @posthog/next
• @posthog/nextjs-config
• @posthog/nuxt
• @posthog/openfeature-node-provider
• @posthog/openfeature-web-provider
• @posthog/rollup-plugin
• @posthog/webpack-plugin
• @posthog/types
• @posthog/browser-common

Checklist

• All commits are signed
• Tests for new code
• Accounted for the impact of any changes across different platforms
• Accounted for backwards compatibility of any changes (no breaking changes!)
• Took care not to unnecessarily increase the bundle size
• Human review completed (required for agent-authored PRs)

If releasing new changes

• Ran pnpm changeset to generate a changeset file

🤖 Agent context

Autonomy: Human-driven (agent-assisted). Peter Olkhovets (@peterolkhov) directed the contribution and is the DRI.

Prepared with Codex using GPT-6.1 Sol at high reasoning, shell/GitHub CLI for source and PR inspection, and pnpm/Vitest/Oxfmt for local validation. Session: local Codex session, not publicly shared.

The existing Node guard and the deferred web follow-up established the intended behavior. The change stays in the numeric adapter; it adds no public options, dependencies, or broader parsing rules. Human review is still required before merge.

DRI: @peterolkhov. Repository permissions prevent this account from setting its own assignee; a maintainer will need to set the assignment.