feat(symbols): skip uploading symbols LaunchDarkly already has

[abelonogov-ld]

Summary

A rebuild that changes one module still re-sent every symbol file, so ldcli symbols upload took time proportional to the whole build rather than to what actually changed. That is most of the wall clock on a large R8 mapping or a fat dSYM.

upload now asks the backend for skip_existing. Any requested key the backend answers with an empty string is reported as already uploaded and skipped, and the summary becomes Successfully uploaded all symbols (N already present). This covers all three upload paths: the generic React Native/Android loop, Apple dSYMs, and Flutter.

Dedup is on by default. It only applies where the key's id is derived from the bytes being uploaded, which the backend decides (launchdarkly/observability#1609): a Version Lane copy still overwrites, and so does a source bundle, since those are keyed by the id of the mapping or image they explain rather than by their own contents. --no-skip-existing forces a full re-upload, for repairing a truncated or corrupt stored object.

Because skipping is a change in what upload does by default, and the closing "Successfully uploaded all symbols" reads the same whether bytes were sent or not, a run that skipped anything now says so on stderr and names the flag. Someone re-uploading to repair a stored object would otherwise take a no-op run for a successful one. The notice is transitional and can come out after a release or two; the counts stay on stdout so scripts parsing them are unaffected.

Backward compatibility: a backend that predates the argument rejects the whole query at validation time, so the request is retried once without it. That keeps a freshly updated CLI working against an older or self-hosted deployment, at the cost of uploading bytes it might not have needed. Only the unknown-argument case is retried, so a credential or project error still reaches the user instead of being silently downgraded.

Depends on launchdarkly/observability#1609, which adds the argument. This should land after that deploys; until then the fallback path keeps upload working unchanged.

How did you test this change?

New tests in cmd/symbols/upload_dedup_test.go, driving getSymbolUploadUrls against an httptest backend that records each request:

• the dedup document and skip_existing: true are sent when enabled, and neither is sent with --no-skip-existing
• an Unknown argument "skip_existing" response triggers exactly one retry, and the retry drops the argument
• any other GraphQL error is returned without a retry
• alreadyUploaded treats only the empty string as a skip
• the summary prints the skipped count on stdout and the notice on stderr, and stays silent on stderr when nothing was skipped

go build ./..., go vet ./cmd/symbols/..., and go test ./cmd/symbols/... pass.

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Note

Medium Risk
Changes default upload behavior and presigned-URL handling across all symbol types; mis-dedup could leave stale symbols, mitigated by opt-out flag and backend digest checks for non-content-keyed bundles.

Overview
ldcli symbols upload skips re-sending symbols the backend already stores, so repeat uploads after unchanged builds avoid large PUTs. Dedup is on by default across the generic React Native/Android path, Apple dSYM, and Flutter flows. The CLI asks get_symbol_upload_urls_ld with skip_existing; an empty presigned URL means skip that key. --no-skip-existing forces a full re-upload for repair scenarios.

Source bundles (Apple/Android --include-sources) are keyed off the mapping/image id, not bundle bytes, so skips use parallel MD5 digests (S3 ETag form) so the backend can match stored content. Flutter Version-lane copies still always get URLs so --app-version overwrites keep working; only Id-lane keys can skip.

Older backends that reject the new GraphQL args get one retry without dedup (only on unknown-argument errors). Completion messaging reports (N already present) on stdout and a stderr note naming --no-skip-existing when anything was skipped.

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[Vadman97]

nice optimization!