feat(analyzers): detect RPC contract changes

[ReubenBond]

Orleans RPC contracts can change without an explicit record of the prior interface shape, making accidental incompatibilities difficult to catch before rolling upgrades.

This adds a grain interface version analyzer and code fixes which compare source interfaces with a GrainInterfaces.txt contract manifest. It reports undeclared interfaces and members, version mismatches, unretired removals, missing manifests, and duplicate declarations, with focused analyzer coverage for versioning, aliases, generics, inheritance, and code fixes.

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull request overview

This PR introduces a new Orleans analyzer + code fix workflow to detect RPC contract drift by comparing grain interfaces in source against a GrainInterfaces.txt manifest, helping prevent accidental incompatibilities during rolling upgrades.

Changes:

• Added GrainInterfaceVersionAnalyzer (ORLEANS0016–ORLEANS0021) to validate interface declarations, versions, members, file presence, retirements, and duplicates.
• Added GrainInterfaceVersionCodeFix to update/create GrainInterfaces.txt entries based on diagnostics.
• Added extensive analyzer/code-fix unit tests and registered new diagnostics in analyzer release notes and resources.

Show a summary per file

File	Description
test/Orleans.Analyzers.Tests/GrainInterfaceVersionAnalyzerTest.cs	Adds coverage for new diagnostics and code fixes across aliases, versions, generics, and inheritance.
src/Orleans.Analyzers/Resources.resx	Adds localized strings for new diagnostics and code fix titles.
src/Orleans.Analyzers/Resources.Designer.cs	Updates strongly-typed resource accessors for the new strings.
src/Orleans.Analyzers/GrainInterfaceVersionCodeFix.cs	Implements code fixes which update/create GrainInterfaces.txt based on diagnostics.
src/Orleans.Analyzers/GrainInterfaceVersionAnalyzer.cs	Implements analyzer + manifest parser for interface/member/version tracking.
src/Orleans.Analyzers/Constants.cs	Adds constants for VersionAttribute FQN and GrainInterfaces.txt filename.
src/Orleans.Analyzers/AnalyzerReleases.Unshipped.md	Documents the newly introduced diagnostic IDs and severities.

Copilot's findings

Files not reviewed (1)

• src/Orleans.Analyzers/Resources.Designer.cs: Generated file

Suppressed comments (2)

src/Orleans.Analyzers/GrainInterfaceVersionCodeFix.cs:366

• AddMemberToFileAsync suppresses insertion when the next interface declaration line StartsWith(interfaceName). This fails when the next interface name happens to share the same prefix (for example, IMyGrain followed by IMyGrainExtended), causing the new member to be inserted in the wrong section.

                // If next line is empty, a comment, or another interface, insert the member here
                if (string.IsNullOrEmpty(nextLine) ||
                    nextLine.StartsWith("#", StringComparison.Ordinal) ||
                    (nextLine.Contains("[Version(") && !nextLine.StartsWith(interfaceName, StringComparison.Ordinal)))
                {

src/Orleans.Analyzers/GrainInterfaceVersionCodeFix.cs:422

• RetireInterfaceInFileAsync uses trimmedLine.Contains(interfaceName), which can retire the wrong interface when one interface name is a substring/prefix of another. It should ensure it matched the full interface-name token before adding the RETIRED prefix.

            // Check if this line contains the interface declaration
            if (trimmedLine.Contains(interfaceName) && trimmedLine.Contains("[Version(") &&
                !trimmedLine.StartsWith(GrainInterfaceVersionAnalyzer.RetiredPrefix, StringComparison.Ordinal))
            {

• Files reviewed: 6/7 changed files
• Comments generated: 4

[Copilot]

Copilot's findings

Files not reviewed (1)

• src/Orleans.Analyzers/Resources.Designer.cs: Generated file

Suppressed comments (1)

src/Orleans.Analyzers/GrainInterfaceVersionCodeFix.cs:263

• AddGrainClassToFileAsync only reactivates an existing contracts entry when the declared CLR name matches className. If a grain class is renamed but keeps a stable [GrainType("...")] alias, the analyzer can still match by alias, but the code fix will append a new entry instead of updating the existing (possibly RETIRED) one. That can introduce duplicate alias declarations, which are treated as errors by the parser (see GrainInterfaceFileParser.Parse duplicate check in GrainInterfaceVersionAnalyzer.cs:1003-1005). Consider matching existing entries by alias (and updating/unretiring that line) before appending a new declaration.

        for (var i = 0; i < lines.Length; i++)
        {
            if (GrainInterfaceFileParser.TryGetGrainClassName(lines[i], out var declaredName)
                && string.Equals(declaredName, className, StringComparison.Ordinal))
            {

• Files reviewed: 23/24 changed files
• Comments generated: 0 new

[Copilot]

Copilot's findings

Files not reviewed (1)

• src/Orleans.Analyzers/Resources.Designer.cs: Generated file

Suppressed comments (1)

src/Orleans.Runtime/OrleansContracts.txt:31

• The contract manifest entry for IGrainDirectoryPartition.GetSnapshotAsync drops the nullable annotation from the return type. The source interface returns ValueTask<GrainDirectoryPartitionSnapshot?>, so this signature should include ? to match the analyzer's contract type rendering (it preserves nullable reference modifiers, e.g., GrainAddress?).

  GetSnapshotAsync(Orleans.Runtime.MembershipVersion, Orleans.Runtime.MembershipVersion, RingRange, System.Threading.CancellationToken) -> ValueTask<GrainDirectoryPartitionSnapshot>

• Files reviewed: 23/24 changed files
• Comments generated: 0 new