SLCORE-2243 Add connected mode and on-demand artifact resolvers

[Krosovok]

No description provided.

[sonar-review-alpha]

Summary

This PR introduces a resolver-based architecture for plugin artifact management in connected mode and on-demand scenarios. The key changes are:

1. Artifact Resolver Pattern: New ConnectedModeArtifactResolver and ConnectedModeCompanionPluginResolver classes handle plugin resolution with automatic scheduling of background downloads when needed.

2. Shared Download Executor: UniqueTaskExecutor deduplicates concurrent plugin downloads for the same connection+plugin combination, preventing redundant work and race conditions.

3. Event Model Refactoring: PluginStatusChangedEvent → PluginStatusUpdateEvent now carries a collection of statuses per connection, enabling batch updates when downloads complete.

4. Centralized Download Logic: ServerPluginDownloader orchestrates all plugin downloads (language and companion) and publishes status events on completion.

What reviewers should know

Start here:

• UniqueTaskExecutor.java — The core innovation: a simple key-based deduplicator ensuring only one download runs per plugin
• ServerPluginDownloader.java — Orchestrates downloads and event publishing
• ConnectedModeArtifactResolver.java — How language plugins are resolved from server storage or scheduled for download

Key logic to understand:

• Language plugins return immediately with SYNCED if locally up-to-date (hash match), or DOWNLOADING if a background fetch is scheduled
• Enterprise languages (SECRETS, IAC, GO) have version gates that are checked before resolution
• The skipSyncPluginKeys mechanism allows IDEs to override server plugins with embedded versions
• Fallback logic handles plugin key renames (e.g., "iacenterprise" → "iac")

Watch for:

• Event publishing happens asynchronously after downloads complete — reviewers should verify events are fired for both success and failure paths
• The isSonarQubeCloudOrVersionAtLeast static method is now shared between resolvers and PluginsService — confirm it's used consistently
• Package moves from ondemand to resolvers touch many imports

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[hashicorp-vault-sonar-prod]

SLCORE-2243

[sonar-review-alpha]

Conclusion: Two real bugs need fixing before merge — companion plugins will silently serve stale jars after a server upgrade, and an unguarded code path in the companion download lambda can leave the UI stuck in DOWNLOADING state indefinitely.

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[Copilot]

Pull request overview

This PR introduces new artifact resolver implementations intended to support downloading analyzers in both connected mode (from server) and on-demand mode (from a remote URL/cache), along with corresponding unit tests.

Changes:

• Add ConnectedModeArtifactResolver to resolve/sync plugins from SonarQube/SonarCloud storage/server plugin lists, including companion plugin handling.
• Add OnDemandArtifactResolver to download/version-cache specific artifacts on demand with signature verification and event publishing.
• Add unit tests covering download scheduling, status reporting, and success/error paths for both resolvers.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 9 comments.

File	Description
backend/core/src/main/java/org/sonarsource/sonarlint/core/plugin/resolvers/ConnectedModeArtifactResolver.java	New connected-mode resolver that reads server plugin lists / storage, schedules downloads, and publishes status update events.
backend/core/src/main/java/org/sonarsource/sonarlint/core/plugin/ondemand/OnDemandArtifactResolver.java	New on-demand resolver that downloads artifacts into a versioned cache, verifies signatures, and publishes status update events.
backend/core/src/test/java/org/sonarsource/sonarlint/core/plugin/ConnectedModeArtifactResolverTest.java	New unit tests validating connected-mode resolver behavior across storage/server/error scenarios.
backend/core/src/test/java/org/sonarsource/sonarlint/core/plugin/ondemand/OnDemandArtifactResolverTest.java	New unit tests validating on-demand resolver behavior for async downloads, caching, and event publishing.

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[sonar-review-alpha]

Conclusion: Solid work overall — the async download pattern, cache management, and version-gate logic are well structured. Two bugs need fixing before merge: a race condition in the synchronous extra-artifact path and a missing error handler in companion-plugin downloads.

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[sonar-review-alpha]

Conclusion: The two resolver classes are well-structured and fit cleanly into the existing architecture. One real test bug and one logic duplication need attention before merge.

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[sonar-review-alpha]

Conclusion: Two real bugs need fixing before merge: one causes a missing status notification that leaves a language permanently stuck in "downloading", and one turns an intended graceful degradation into an uncaught exception. See inline comments.

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[sonar-review-alpha]

Conclusion: Most of the previous round's issues have been addressed cleanly — the companion-hash check, the stuck-in-DOWNLOADING bug, scheduleIfNotInProgress extraction, and the blocking test helper are all fixed. Three issues remain open: the IAC fallback event notification bug (real data loss in production), the useless null guard on version(), and the isSonarCloud ternary duplication.

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[sonar-review-alpha]

Conclusion: Four of the five previously flagged issues are properly resolved. The IAC fallback notification bug (ID 2972231832) is still present and needs fixing before merge.

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[sonar-review-alpha]

Conclusion: Clean, well-structured refactor with good test coverage. One logic duplication worth collapsing before this pattern drifts further.

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[sonar-review-alpha]

Conclusion: The two previously flagged issues remain unaddressed. The IAC fallback bug (#2972231832) is a functional defect that will leave ANSIBLE and GITHUBACTIONS languages stuck in DOWNLOADING state permanently on any server that does not have iacenterprise but has iac.

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[sonarqube-next]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0 Dependency risks
83.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[sonar-review-alpha]

Conclusion: The logic duplication issue is cleanly resolved. The IAC fallback notification bug is still present and needs fixing before merge.

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