Don't cache known-broken compositions #80021
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Right now we have an issue where users are getting broken MEF compositions cached on their machines, so subsequent launches of the product are operating on a broken composition. It's not "broken" in the sense that "the cache cannot be loaded" but rather the content of the cache is just missing most of our MEF parts. As a defense-in- depth change to deal with potential transient issues, let's not cache compositions we know are bad.
CyrusNajmabadi
approved these changes
Aug 22, 2025
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Slightly concerned that someone could always be in a bad state (say for some other component we don't care about). So we recreate every time. Maybe log telemetry? |
CyrusNajmabadi
approved these changes
Aug 22, 2025
| foreach (var exception in catalog.DiscoveredParts.DiscoveryErrors) | ||
| { | ||
| hasErrors = true; | ||
| LogError($"Encountered exception in the MEF composition: {exception.Message}"); |
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Will this come back to us as telemetry?
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And yes, at least indirectly: this goes through the gold bar reporting, which then logs telemetry for this message. I can see telemetry for myself or @phil-allen-msft hitting this exact line.
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@CyrusNajmabadi I think we've already got telemetry logging those errors; digging into that further. |
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@CyrusNajmabadi And if there is a failure, we will log a gold bar for that failure. So it won't be quiet. Right now we're seeing cases where we fail, but you won't see the root cause since we cached the compositon which leads to downstream failure. This way if something is stuck, we'll at least recreate and see the same original failure. |
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Wfm! |
dibarbet
approved these changes
Aug 22, 2025
JoeRobich
approved these changes
Aug 22, 2025
AbhitejJohn
approved these changes
Aug 22, 2025
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/backport to release/dev18.0 |
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Started backporting to release/dev18.0: https://github.com/dotnet/roslyn/actions/runs/17169243126 |
This was referenced Aug 29, 2025
JoeRobich
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Aug 29, 2025
46 PRs before and 36 after ```diff + * [Cache diagnostic analyzer computation](dotnet/roslyn#80045) + * [Remove parameter always passed the same value](dotnet/roslyn#80042) * [Update doc for IMethodSymbol.IsExtensionMethod](dotnet/roslyn#80016) * [Don't cache known-broken compositions](dotnet/roslyn#80021) * [Cleanup methods in DiagAnalyzerService](dotnet/roslyn#80013) * [Simplify processing of errors reported by the build](dotnet/roslyn#79964) * [Additional cleanup of the DiagnosticAnalyzerServier](dotnet/roslyn#80005) * [Fix Code Lens around source generated files](dotnet/roslyn#79992) * [Remove superflous DiagService api that can be achieved with existing apis](dotnet/roslyn#80007) * [Generate `init` accessor for required properties inside `readonly struct`s](dotnet/roslyn#80004) * [Remove existing low level diag oop code now that it's all handled at higher levels.](dotnet/roslyn#79994) * [Allow large InlineHint ArrayBuilder pooling](dotnet/roslyn#79857) * [Reduce allocations obtaining classified spans in ClassifierHelper](dotnet/roslyn#79856) * [Compute span diagnostics in oop](dotnet/roslyn#79991) * [Allow Razor cohosting to work with non-Razor SDK projects](dotnet/roslyn#79953) * [Move computation of deprioritized analyzers to oop](dotnet/roslyn#79989) * [EnC: Fix symbol mapping of delegates with indexed name](dotnet/roslyn#79837) * [Emit telemetry 'durations' with known radix point '.'](dotnet/roslyn#79988) * [Move logic up into DiagService](dotnet/roslyn#79985) * [Move the StateManager type up to the DiagnosticService from the DiagnosticIncrementalANalyzer](dotnet/roslyn#79984) * [Immediately remote diagnostics call to OOP](dotnet/roslyn#79983) * [Build Microsoft.CodeAnalysis.SemanticSearch.Extension ref assembly for use in semantic search queries](dotnet/roslyn#79972) * [Only cache compilation if we have the same set of analyzers](dotnet/roslyn#79978) * [Delete unused property](dotnet/roslyn#79963) * [Update 'use expr body' to be a purely syntactic analyzer](dotnet/roslyn#79979) * [Mark 'Use expr body' as a syntax-only fixer](dotnet/roslyn#79971) * [♻️ MSBuildWorkspaceDirectory - Fallback to AppContext.BaseDirectory when Assembly Location is empty](dotnet/roslyn#79934) * [Merge runtime async support into main](dotnet/roslyn#79833) * [Implement "Simplify property accessor" feature](dotnet/roslyn#79754) - * Merge main to runtime async branch (PR: [#79961](dotnet/roslyn#79961)) * [Redo how and when we report source generator telemetry](dotnet/roslyn#79951) * [Allow MEF components to supply assembly path resolvers](dotnet/roslyn#79218) * [Allow Razor to hook up the source generator in misc files](dotnet/roslyn#79891) * [Block ENC for extension blocks](dotnet/roslyn#79883) * [Upgrade servicehub.client to fix test source discovery](dotnet/roslyn#79899) * [Update package restore error message.](dotnet/roslyn#79876) - * Merge main (PR: [#79834](dotnet/roslyn#79834)) - * Merge main (PR: [#79830](dotnet/roslyn#79830)) * [Baseline struct lifting tests](dotnet/roslyn#79505) - * Merge main to runtime async branch (PR: [#79582](dotnet/roslyn#79582)) - * Merge main (PR: [#79424](dotnet/roslyn#79424)) - * Merge main (PR: [#78994](dotnet/roslyn#78994)) - * Merge main to runtime async branch (PR: [#78740](dotnet/roslyn#78740)) - * Merge main to runtime async branch (PR: [#78517](dotnet/roslyn#78517)) - * Merge main to runtime async branch (PR: [#78114](dotnet/roslyn#78114)) - * Merge main to runtime async branch (PR: [#77700](dotnet/roslyn#77700)) - * Merge main to runtime async branch (PR: [#77533](dotnet/roslyn#77533)) - * Merge main to runtime async branch (PR: [#77265](dotnet/roslyn#77265)) ```
This was referenced Sep 8, 2025
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Right now we have an issue where users are getting broken MEF compositions cached on their machines, so subsequent launches of the product are operating on a broken composition. It's not "broken" in the sense that "the cache cannot be loaded" but rather the content of the cache is just missing most of our MEF parts. As a defense-in-depth change to deal with potential transient issues, let's not cache compositions we know are bad.