RUBY-3838 Fix raise_on_invalid handling and protect SRV monitor thread

[comandeo-mongo]

Background

Mongo::Srv::Resolver#raise_on_invalid? always returns true because of
operator precedence in @options[:raise_on_invalid] || true.

Changes

• lib/mongo/srv/resolver.rb — raise_on_invalid? now uses
  @options.fetch(:raise_on_invalid, true). The ||= memoization on a
  Boolean is also dropped (same footgun as the || precedence bug).
• lib/mongo/srv/monitor.rb — the polling resolver is now constructed
  with raise_on_invalid: false per the polling-srv-records spec
  (mismatched-domain records and empty results MUST be logged and skipped,
  not raised). Adds a defensive rescue Mongo::Error in scan! so any
  Mongo error leaking out of the resolver cannot terminate the SRV monitor
  thread.
• lib/mongo/uri/srv_protocol.rb — RUBY-3743 changed this resolver to
  raise_on_invalid: false, but the resolver bug masked the change so it
  was never live. The Initial DNS Seedlist Discovery spec mandates that an
  error MUST be raised on domain mismatch or empty result during initial URI
  parsing, so this is reverted to the default raise_on_invalid: true and
  the docstring is corrected.

Spec citations

• Polling SRV Records for mongos discovery: "MUST NOT raise an error" for
  both mismatched-domain records and empty/error DNS results (lines 60, 66
  of polling-srv-records-for-mongos-discovery.md).
• Initial DNS Seedlist Discovery: "an error MUST be raised" for empty/no
  records, and "Drivers MUST raise an error and MUST NOT initiate a
  connection" for hostnames not matching the parent domain (lines 123-130).

Test plan

• New unit specs in spec/mongo/srv/resolver_spec.rb cover both branches
  of raise_on_invalid for mismatched-domain and empty-result cases.
• New monitor specs verify scan! does not propagate
  MismatchedDomain or NoSRVRecords from the resolver.
• bundle exec rspec spec/mongo/srv/ spec/mongo/uri/srv_protocol_spec.rb
  → 218 examples, 0 failures.
• bundle exec rspec spec/spec_tests/seed_list_discovery_spec.rb → 106
  examples, 0 failures.
• bundle exec rubocop clean on touched files.

Jira

https://jira.mongodb.org/browse/RUBY-3838

[Copilot]

Pull request overview

Fixes SRV resolution error-handling so raise_on_invalid behaves as intended, aligns initial vs polling SRV behavior with the relevant specs, and hardens the SRV monitor loop against unexpected resolver-raised Mongo::Errors that could otherwise terminate the monitor thread.

Changes:

• Correct Mongo::Srv::Resolver#raise_on_invalid? to properly honor :raise_on_invalid with a default of true.
• Force the SRV polling monitor’s resolver into “log-and-continue” mode (raise_on_invalid: false) and defensively rescue Mongo::Error in scan!.
• Revert initial URI parsing resolver behavior to default “raise on invalid” and update the SRVProtocol resolver docstring accordingly.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
lib/mongo/srv/resolver.rb	Fixes raise_on_invalid? defaulting logic so false is respected and default true works correctly.
lib/mongo/srv/monitor.rb	Ensures polling SRV lookups don’t raise on invalid/empty results and prevents monitor thread termination from leaked Mongo::Errors.
lib/mongo/uri/srv_protocol.rb	Restores initial seedlist discovery behavior to raise on invalid/empty SRV results and updates documentation to match spec intent.
spec/mongo/srv/resolver_spec.rb	Adds unit coverage for both raise_on_invalid: false and default true behaviors for mismatched-domain and empty results.
spec/mongo/srv/monitor_spec.rb	Adds coverage asserting scan! does not propagate MismatchedDomain / NoSRVRecords from the resolver and keeps topology unchanged.

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