codeintel: Ensure we represent every referenced symbol in a SCIP index (

#46390)

enterprise/internal/codeintel/uploads/internal/background/scip.go

@@ -73,6 +73,12 @@ func correlateSCIP(
 				if pkg, ok := packageFromSymbol(symbol.Symbol); ok {
 					packageSet[pkg] = false
 				}
+
+				for _, relationship := range symbol.Relationships {
+					if pkg, ok := packageFromSymbol(relationship.Symbol); ok {
+						packageSet[pkg] = false
+					}
+				}
 			}
 
 			for _, occurrence := range document.Occurrences {
@@ -265,25 +271,56 @@ func canonicalizeDocument(document *scip.Document, externalSymbolsByName map[str
 // if there is an occurrence that references the external symbol name and no local symbol information
 // exists.
 func injectExternalSymbols(document *scip.Document, externalSymbolsByName map[string]*scip.SymbolInformation) {
-	symbolNames := make(map[string]struct{}, len(document.Symbols))
+	// Build set of existing definitions
+	definitionsSet := make(map[string]struct{}, len(document.Symbols))
 	for _, symbol := range document.Symbols {
-		symbolNames[symbol.Symbol] = struct{}{}
+		definitionsSet[symbol.Symbol] = struct{}{}
 	}
 
+	// Build a set of occurrence and symbol relationship references
+	referencesSet := make(map[string]struct{}, len(document.Symbols))
+	for _, symbol := range document.Symbols {
+		for _, relationship := range symbol.Relationships {
+			referencesSet[relationship.Symbol] = struct{}{}
+		}
+	}
 	for _, occurrence := range document.Occurrences {
 		if occurrence.Symbol == "" || scip.IsLocalSymbol(occurrence.Symbol) {
 			continue
 		}
 
-		// Ensure we only add each symbol once
-		if _, ok := symbolNames[occurrence.Symbol]; ok {
-			continue
-		}
-		symbolNames[occurrence.Symbol] = struct{}{}
+		referencesSet[occurrence.Symbol] = struct{}{}
+	}
+
+	// Add any references that do not have an associated definition
+	for len(referencesSet) > 0 {
+		// Collect unreferenced symbol names for new symbols. This can happen if we have
+		// a set of external symbols that reference each other. The references set acts
+		// as the frontier of our search.
+		newReferencesSet := map[string]struct{}{}
 
-		if symbol, ok := externalSymbolsByName[occurrence.Symbol]; ok {
+		for symbolName := range referencesSet {
+			if _, ok := definitionsSet[symbolName]; ok {
+				continue
+			}
+			definitionsSet[symbolName] = struct{}{}
+
+			symbol, ok := externalSymbolsByName[symbolName]
+			if !ok {
+				continue
+			}
+
+			// Add new definition for referenced symbol
 			document.Symbols = append(document.Symbols, symbol)
+
+			// Populate new frontier
+			for _, relationship := range symbol.Relationships {
+				newReferencesSet[relationship.Symbol] = struct{}{}
+			}
 		}
+
+		// Continue resolving references while we added new symbols
+		referencesSet = newReferencesSet
 	}
 }