warn for fields which no longer work (#471)

1 files changed, 98 insertions, 0 deletions

diff --git a/src/SMAPI.ModBuildConfig.Analyzer/ObsoleteFieldAnalyzer.cs b/src/SMAPI.ModBuildConfig.Analyzer/ObsoleteFieldAnalyzer.cs
new file mode 100644
index 00000000..00565329
--- /dev/null
+++ b/src/SMAPI.ModBuildConfig.Analyzer/ObsoleteFieldAnalyzer.cs
@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace StardewModdingAPI.ModBuildConfig.Analyzer
+{
+    /// <summary>Detects references to a field which has been replaced.</summary>
+    [DiagnosticAnalyzer(LanguageNames.CSharp)]
+    public class ObsoleteFieldAnalyzer : DiagnosticAnalyzer
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>Maps obsolete fields/properties to their non-obsolete equivalent.</summary>
+        private readonly IDictionary<string, string> ReplacedFields = new Dictionary<string, string>
+        {
+            // Farmer
+            ["StardewValley.Farmer::friendships"] = "friendshipData"
+        };
+
+        /// <summary>Describes the diagnostic rule covered by the analyzer.</summary>
+        private readonly IDictionary<string, DiagnosticDescriptor> Rules = new Dictionary<string, DiagnosticDescriptor>
+        {
+            ["SMAPI003"] = new DiagnosticDescriptor(
+                id: "SMAPI003",
+                title: "Reference to obsolete field",
+                messageFormat: "The '{0}' field is obsolete and should be replaced with '{1}'. See https://smapi.io/buildmsg/smapi003 for details.",
+                category: "SMAPI.CommonErrors",
+                defaultSeverity: DiagnosticSeverity.Warning,
+                isEnabledByDefault: true,
+                helpLinkUri: "https://smapi.io/buildmsg/smapi003"
+            )
+        };
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The descriptors for the diagnostics that this analyzer is capable of producing.</summary>
+        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        public ObsoleteFieldAnalyzer()
+        {
+            this.SupportedDiagnostics = ImmutableArray.CreateRange(this.Rules.Values);
+        }
+
+        /// <summary>Called once at session start to register actions in the analysis context.</summary>
+        /// <param name="context">The analysis context.</param>
+        public override void Initialize(AnalysisContext context)
+        {
+            // SMAPI003: avoid obsolete fields
+            context.RegisterSyntaxNodeAction(
+                this.AnalyzeObsoleteFields,
+                SyntaxKind.SimpleMemberAccessExpression
+            );
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Analyse a syntax node and add a diagnostic message if it references an obsolete field.</summary>
+        /// <param name="context">The analysis context.</param>
+        private void AnalyzeObsoleteFields(SyntaxNodeAnalysisContext context)
+        {
+            try
+            {
+                // get reference info
+                MemberAccessExpressionSyntax node = (MemberAccessExpressionSyntax)context.Node;
+                ITypeSymbol declaringType = context.SemanticModel.GetTypeInfo(node.Expression).Type;
+                string propertyName = node.Name.Identifier.Text;
+
+                // suggest replacement
+                for (ITypeSymbol type = declaringType; type != null; type = type.BaseType)
+                {
+                    if (this.ReplacedFields.TryGetValue($"{type}::{propertyName}", out string replacement))
+                    {
+                        context.ReportDiagnostic(Diagnostic.Create(this.Rules["SMAPI003"], context.Node.GetLocation(), $"{type}.{propertyName}", replacement));
+                        break;
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                throw new InvalidOperationException($"Failed processing expression: '{context.Node}'. Exception details: {ex.ToString().Replace('\r', ' ').Replace('\n', ' ')}");
+            }
+        }
+    }
+}