[dailyun]

kong.JSON resolves numbers as float64. A value such as 1e40 is then silently stored as +Inf in a float32 field, while passing the same value through --value=1e40 already returns an error.

Reject finite resolved values that overflow to infinity when narrowed to float32. Keep float64 fields, explicit infinities from custom resolvers, and values just above MaxFloat32 that still round to a finite value working as before.

Minimal reproduction:

var cli struct{ Value float32 }
resolver, _ := kong.JSON(strings.NewReader(`{"value": 1e40}`))
parser, _ := kong.New(&cli, kong.Resolvers(resolver))
_, err := parser.Parse(nil)
// Before: err == nil, cli.Value == +Inf. After: a float32 range error.

Validation on Go 1.26.7/macOS arm64:

• Positive and negative JSON overflow cases fail against unchanged source and pass with the fix.
• Added controls for CLI overflow, rounding at the float32 limit, large valid float64 values and explicit resolved infinities.
• go test ./... -count=1, go test -race ./... -count=1, and the pinned golangci-lint 1.64.5 pass.
• go vet -structtag=false ./... passes (the project intentionally supports bare struct-tag keys).

No public API or dependency changes. Implemented and tested with Codex through the dailyun account; no independent human review is claimed.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-21T09:53:55.025534Z	12d9c60	PR opened

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