mark snapshots with failed rebuilds as vintage

Author: tayloraswift

Sources/UnidocDB/Snapshots/Unidoc.DB.Snapshots.swift

@@ -40,9 +40,10 @@ extension Unidoc.DB.Snapshots
     }
 
     public static
-    let indexSymbolGraphABI:Mongo.CollectionIndex = .init("ABI",
+    let indexSymbolGraphABI:Mongo.CollectionIndex = .init("ABI/2",
         unique: false)
     {
+        $0[Unidoc.Snapshot[.vintage]] = (+)
         $0[Unidoc.Snapshot[.metadata] / SymbolGraphMetadata[.abi]] = (+)
     }
 
@@ -207,6 +208,9 @@ extension Unidoc.DB.Snapshots
             {
                 $0[.filter]
                 {
+                    //  This needs to be ``BSON.Null`` and not just `{ $0[.exists] = false }`,
+                    //  otherwise it will not use the partial index.
+                    $0[Unidoc.Snapshot[.vintage]] = BSON.Null.init()
                     $0[Unidoc.Snapshot[.metadata] / SymbolGraphMetadata[.abi]]
                     {
                         $0[.lt] = version

Sources/UnidocRecords/Packages/Unidoc.Snapshot.swift

@@ -39,15 +39,34 @@ extension Unidoc
         public
         var size:Int64
 
-        @inlinable internal
+        /// Indicates if the symbol graph is no longer buildable from source. This flag prevents
+        /// the automated build system from repeatedly attempting to build the package.
+        ///
+        /// Possible reasons for this include:
+        ///
+        /// -   The package no longer compiles using the latest version of its dependencies,
+        ///     and its manifest does not constrain the dependencies to compatible versions.
+        ///
+        /// -   The package, or one of its dependencies, has been taken down from GitHub.
+        ///
+        /// -   The package only builds on a platform that is no longer supported by the hosting
+        ///     service.
+        ///
+        /// -   The package suffers from a Swift (or Unidoc) compiler bug that prevents it from
+        ///     being built.
+        public
+        var vintage:Bool
+
+        @inlinable
         init(id:Edition,
             metadata:SymbolGraphMetadata,
             inline:SymbolGraph?,
             action:LinkerAction?,
             swift:PatchVersion?,
             pins:[Edition?],
             type:GraphType,
-            size:Int64)
+            size:Int64,
+            vintage:Bool)
         {
             self.id = id
             self.metadata = metadata
@@ -57,6 +76,7 @@ extension Unidoc
             self.pins = pins
             self.type = type
             self.size = size
+            self.vintage = vintage
         }
     }
 }
@@ -87,7 +107,8 @@ extension Unidoc.Snapshot
             swift: swift,
             pins: [],
             type: .bson,
-            size: 0)
+            size: 0,
+            vintage: false)
     }
 }
 extension Unidoc.Snapshot
@@ -155,6 +176,7 @@ extension Unidoc.Snapshot
         case pins = "p"
         case type = "T"
         case size = "B"
+        case vintage = "V"
 
         @available(*, deprecated, renamed: "inline")
         @inlinable public static
@@ -179,6 +201,7 @@ extension Unidoc.Snapshot:BSONDocumentEncodable
         bson[.pins] = self.pins.isEmpty ? nil : self.pins
         bson[.type] = self.type
         bson[.size] = self.size
+        bson[.vintage] = self.vintage ? true : nil
     }
 }
 extension Unidoc.Snapshot:BSONDocumentDecodable
@@ -193,6 +216,7 @@ extension Unidoc.Snapshot:BSONDocumentDecodable
             swift: try bson[.swift]?.decode(),
             pins: try bson[.pins]?.decode() ?? [],
             type: try bson[.type]?.decode() ?? .bson,
-            size: try bson[.size]?.decode() ?? 0)
+            size: try bson[.size]?.decode() ?? 0,
+            vintage: try bson[.vintage]?.decode() ?? false)
     }
 }

Sources/UnidocServer/Operations/Procedures/Unidoc.BuilderUploadOperation.swift

@@ -72,15 +72,25 @@ extension Unidoc.BuilderUploadOperation:Unidoc.BlockingOperation
 
             try await db.completeBuilds.upsert(complete)
 
-            if  case .success(let snapshot) = build.outcome
+            switch build.outcome
             {
+            case .success(let snapshot):
                 try await db.snapshots.upsert(snapshot)
 
                 /// A successful (labeled) build also sets the platform preference, since we now
                 /// know that the package can be built on that platform.
                 let _:Unidoc.PackageMetadata? = try await db.packages.reset(
                     platformPreference: snapshot.metadata.triple,
                     of: snapshot.id.package)
+
+            case .failure:
+                //  Mark the snapshot as unbuildable, so that automated plugins don’t try to
+                //  build it again.
+                let _:Unidoc.Snapshot? = try await db.snapshots.modify(
+                    existing: complete.id.edition)
+                {
+                    $0[.set] { $0[Unidoc.Snapshot[.vintage]] = true }
+                }
             }
 
         case .labeling: