fix(node/net): return string `family` in `server.address()`

[nrako]

Summary

Aligns Deno's Node.js compatibility layer (node:net, node:http, node:https, node:http2, node:dns) with Node.js v18.4.0+ behavior by returning the family property as a string ("IPv4" or "IPv6") rather than a number in server.address() and socket address methods.

Node.js briefly changed family from string to number in v18.0.0 (nodejs/node#41431), but reverted in v18.4.0 (nodejs/node#43054) due to ecosystem breakage (nodejs/node#43014).

This fix ensures compatibility with npm packages that rely on the string format, which has been the stable API since Node.js v18.4.0.

Changes

• Modified ext/node/polyfills/http.ts to add family property to address() return
• Modified ext/node/polyfills/internal_binding/tcp_wrap.ts to return string family instead of number in getsockname(), getpeername(), and #connect()
• Modified ext/node/polyfills/net.ts to fix socket.remoteFamily getter (no longer needs conversion since family is now a string)
• Modified ext/node/polyfills/dns.ts and ext/node/polyfills/internal/dns/promises.ts to accept string family values ("IPv4", "IPv6") in lookup(), matching Node.js behavior
• Added tests in tests/unit_node/http_test.ts, tests/unit_node/http2_test.ts, tests/unit_node/https_test.ts, tests/unit_node/dns_test.ts, and tests/unit_node/net_test.ts

Node.js Compatibility Note

For non-IP addresses (when isIP() returns 0), the family property is undefined. This matches Node.js C++ behavior in AddressToJS where family is only set for AF_INET ("IPv4") and AF_INET6 ("IPv6"), and left undefined otherwise.

Refs

• nodejs/node#43054
• nodejs/node@70b516e

[coderabbitai[bot]]

Walkthrough

Adds export getIPFamily(ip) and uses it to represent IP family as string literals ("IPv4"/"IPv6") in TCP internals and AddressInfo.family in ext/node/polyfills/internal_binding/tcp_wrap.ts. ServerImpl.address() now returns { port, address, family } in ext/node/polyfills/http.ts. Socket.remoteFamily getter in ext/node/polyfills/net.ts was changed to return the raw numeric family. DNS lookup handling in ext/node/polyfills/dns.ts and ext/node/polyfills/internal/dns/promises.ts accepts string family values and maps them to numeric 4/6. New tests for http, http2, https, dns, and net validate family behavior.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: returning string family in server.address() for Node.js compatibility.
Description check	✅ Passed	The description thoroughly explains the changeset, including context (Node.js version history), affected modules, and the rationale for the changes.

✨ Finishing touches

• [ ] 📝 Generate docstrings

🧪 Generate unit tests (beta)

• [ ] Create PR with unit tests
• [ ] Post copyable unit tests in a comment

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• ext/node/polyfills/http.ts (2 hunks)
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• ext/node/polyfills/internal/net.ts
• ext/node/polyfills/http.ts

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[nrako]

Thanks for the review. Let me know if I should fix up the last commit, or anything else. I look forward to seeing this fix released— I've encountered this issue while trying to use the latest version of Playwright in a Deno web project.

[Tango992]

Thanks, no action is needed from your side. In the meantime can do deno upgrade --canary if you'd like to try the fix.