Fix: Respect injection point specifier with shift. (FabricMC#187)

Gated since this is technically breaking.

Author: LlamaLad7

gradle.properties

@@ -4,7 +4,7 @@ packaging=jar
 description=Mixin (Fabric fork)
 url=https://fabricmc.net
 organization=FabricMC
-buildVersion=0.16.4
+buildVersion=0.16.5
 upstreamMixinVersion=0.8.7
 buildType=RELEASE
 asmVersion=9.8

src/main/java/org/spongepowered/asm/mixin/FabricUtil.java

@@ -49,10 +49,15 @@ public final class FabricUtil {
      */
     public static final int COMPATIBILITY_0_14_0 = 14000; // 0.14.0+mixin.0.8.6
 
+    /**
+     * Fabric compatibility version 0.16.5
+     */
+    public static final int COMPATIBILITY_0_16_5 = 16005; // 0.16.5+mixin.0.8.7
+
     /**
      * Latest compatibility version
      */
-    public static final int COMPATIBILITY_LATEST = COMPATIBILITY_0_14_0;
+    public static final int COMPATIBILITY_LATEST = COMPATIBILITY_0_16_5;
 
     public static String getModId(IMixinConfig config) {
         return getModId(config, "(unknown)");

src/main/java/org/spongepowered/asm/mixin/injection/InjectionPoint.java

@@ -45,6 +45,7 @@
 import org.objectweb.asm.tree.AnnotationNode;
 import org.objectweb.asm.tree.InsnList;
 import org.objectweb.asm.tree.MethodNode;
+import org.spongepowered.asm.mixin.FabricUtil;
 import org.spongepowered.asm.mixin.MixinEnvironment;
 import org.spongepowered.asm.mixin.MixinEnvironment.Option;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInjector;
@@ -552,14 +553,20 @@ static final class Shift extends InjectionPoint {
 
         private final InjectionPoint input;
         private final int shift;
+        private final boolean respectSpecifier;
 
         public Shift(InjectionPoint input, int shift) {
+            this(input, shift, FabricUtil.COMPATIBILITY_LATEST);
+        }
+
+        public Shift(InjectionPoint input, int shift, int fabricCompatibility) {
             if (input == null) {
                 throw new IllegalArgumentException("Must supply an input injection point for SHIFT");
             }
 
             this.input = input;
             this.shift = shift;
+            this.respectSpecifier = fabricCompatibility >= FabricUtil.COMPATIBILITY_0_16_5;
         }
 
         /* (non-Javadoc)
@@ -606,6 +613,11 @@ public boolean find(String desc, InsnList insns, Collection<AbstractInsnNode> no
 
             return nodes.size() > 0;
         }
+
+        @Override
+        public Specifier getSpecifier(Specifier defaultSpecifier) {
+            return this.respectSpecifier ? this.input.getSpecifier(defaultSpecifier) : super.getSpecifier(defaultSpecifier);
+        }
     }
 
     /**
@@ -871,15 +883,17 @@ private static InjectionPoint create(IMixinContext context, InjectionPointData d
 
     private static InjectionPoint shift(IInjectionPointContext context, InjectionPoint point,
             At.Shift shift, int by) {
+
+        int fabricCompatibility = FabricUtil.getCompatibility(context);
 
         if (point != null) {
             if (shift == At.Shift.BEFORE) {
-                return InjectionPoint.before(point);
+                return new InjectionPoint.Shift(point, -1, fabricCompatibility);
             } else if (shift == At.Shift.AFTER) {
-                return InjectionPoint.after(point);
+                return new InjectionPoint.Shift(point, 1, fabricCompatibility);
             } else if (shift == At.Shift.BY) {
                 InjectionPoint.validateByValue(context.getMixin(), context.getMethod(), context.getAnnotationNode(), point, by);
-                return InjectionPoint.shift(point, by);
+                return new InjectionPoint.Shift(point, by, fabricCompatibility);
             }
         }