[PDGGK]

Fixes #40730.

#40729 removed the gcpopts import from gcsx. This change handles the other regression listed in the issue. #40379 made core/runtime/xlangx import options/jobopts to read --resource_hints. The root beam package imports xlangx, so any binary that imports beam now registers all of jobopts' flags on flag.CommandLine: --endpoint, --job_name, --async, --experiments, --parallelism and the rest. A binary or test that defines a flag with one of those names panics at startup.

The repro from the issue, run unchanged as a test in a separate module against each Beam version:

# github.com/apache/beam/sdks/v2 v2.77.0
ok  	repro	0.504s

# github.com/apache/beam/sdks/v2 v2.78.0-RC1
panic: /var/folders/…/repro.test flag redefined: endpoint
FAIL	repro	0.367s

# master at 99dbd880e07
panic: /var/folders/…/repro.test flag redefined: endpoint
FAIL	repro	0.377s

# master with this change
ok  	repro	0.359s

Both #40379 and #40729 are in sdks/v2.78.0-RC1. 2.78.0 therefore fixes the --project collision but still has this one.

Change

• xlangx now looks up --resource_hints by name with flag.Lookup, as gcsx.GetGcsEndpoint does since [Go] Avoid importing gcpopts in gcsx and dataflowlib to prevent flag collisions #40729. If the flag isn't registered, nothing could have set it, and no hints are forwarded.
• The hint parsing moves from jobopts.GetPipelineResourceHints into a new resource.ParseHints, which both packages can use without registering flags. jobopts.GetPipelineResourceHints stays as a wrapper, so its API is unchanged.
• jobopts' stringSlice.Get() returns a []string rather than the unexported stringSlice type, so the value can be read through flag.Getter from outside the package.

After this, go list -deps ./go/pkg/beam no longer lists options/jobopts, as in v2.77.0.

The issue's long-term point, that runners register flags in init(), is out of scope here.

Testing

New tests:

• TestNoJobSubmissionFlags (xlangx): asserts the xlangx test binary has no --endpoint, --job_name or --resource_hints flag. If the jobopts import is put back in expand.go, it fails with flag --endpoint is registered (usage "Job service endpoint (required)."), plus the same message for the other two flags.
• TestPipelineResourceHints (xlangx): covers the lookup with the flag unregistered, and with two --resource_hints values.
• TestResourceHintsFlagGetter (jobopts): pins the []string result of Get() that xlangx relies on. If Get() returns s again, it fails.
• TestParseHints (resource): the previous jobopts parsing test, moved with the same inputs and assertions.

I also checked that the #40379 behaviour still works end to end, through exported API only. A test module imports jobopts (as a runner does), sets --resource_hints=min_ram=2GB, and calls beam.TryCrossLanguage against a handler registered with xlangx.RegisterHandler. The captured ExpansionRequest has beam:option:resource_hints:v1 = ["min_ram=2000000000B"], both on v2.78.0-RC1 and with this change.

Run locally:

• go test for options/..., core/runtime/xlangx/..., runners/universal/..., runners/dataflow and the root beam package: all pass.
• gofmt -l, go vet --copylocks=false --unsafeptr=false and staticcheck 2026.2 on the touched packages: all clean.

The full ./go/pkg/... run and the cross-language integration tests are left to CI.

[github-actions]

📋 Review Summary

This PR cleanly resolves flag redefinition panics (#40730) caused by xlangx importing jobopts (which is transitively imported by the root beam package). Moving resource hint parsing to resource.ParseHints, updating jobopts.stringSlice.Get() to return []string, and looking up --resource_hints via flag.Lookup in xlangx effectively decouples the packages while preserving cross-language resource hint forwarding.

🔍 General Feedback

• The architectural separation between options/resource, options/jobopts, and core/runtime/xlangx is clean and aligns well with the approach used in #40729.
• Unit tests thoroughly cover the new flag lookup behavior, flag.Getter contract on stringSlice, hint parsing, and regression prevention against job submission flag registration in xlangx.

---

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[codecov]

Codecov Report

❌ Patch coverage is 81.57895% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.43%. Comparing base (12bbb17) to head (9d06578).
⚠️ Report is 20 commits behind head on master.

Files with missing lines	Patch %	Lines
sdks/go/pkg/beam/options/resource/hint.go	79.31%	4 Missing and 2 partials ⚠️
sdks/go/pkg/beam/core/runtime/xlangx/expand.go	85.71%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #40944       +/-   ##
===========================================
- Coverage   79.83%   56.43%   -23.41%     
===========================================
  Files         494      876      +382     
  Lines       83575   154761    +71186     
===========================================
+ Hits        66722    87339    +20617     
- Misses      16853    65566    +48713     
- Partials        0     1856     +1856     

Flag	Coverage Δ
go	28.98% <81.57%> (?)

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[github-actions]

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[jrmccluskey]

Bringing in @derrickaw since he worked on the first PR addressing this issue

[derrickaw]

Bringing in @derrickaw since he worked on the first PR addressing this issue

@shunping might be better with the option changes since he has been doing a lot of design work with this recently. Thanks

[shunping]

Ack! I will take a look this week.