Always discourage shifting in injectors that can't inject anywhere (such as Redirect)

Author: Earthcomputer

src/main/kotlin/platform/mixin/handlers/InjectAnnotationHandler.kt

@@ -138,5 +138,7 @@ class InjectAnnotationHandler : InjectorAnnotationHandler() {
 
     override val allowCoerce = true
 
+    override val isShiftAlwaysDiscouraged = false
+
     override val mixinExtrasExpressionContextType = ExpressionContext.Type.INJECT
 }

src/main/kotlin/platform/mixin/handlers/InjectorAnnotationHandler.kt

@@ -178,6 +178,8 @@ abstract class InjectorAnnotationHandler : MixinAnnotationHandler {
 
     open val allowCoerce = false
 
+    open val isShiftAlwaysDiscouraged = true
+
     override val isEntryPoint = true
 
     override val icon = MixinAssets.MIXIN_INJECTOR_ICON

src/main/kotlin/platform/mixin/handlers/ModifyVariableHandler.kt

@@ -89,5 +89,7 @@ class ModifyVariableHandler : InjectorAnnotationHandler() {
         return result
     }
 
+    override val isShiftAlwaysDiscouraged = false
+
     override val mixinExtrasExpressionContextType = ExpressionContext.Type.MODIFY_VARIABLE
 }

src/main/kotlin/platform/mixin/inspection/injector/DiscouragedShiftInspection.kt

@@ -20,6 +20,8 @@
 
 package com.demonwav.mcdev.platform.mixin.inspection.injector
 
+import com.demonwav.mcdev.platform.mixin.handlers.InjectorAnnotationHandler
+import com.demonwav.mcdev.platform.mixin.handlers.MixinAnnotationHandler
 import com.demonwav.mcdev.platform.mixin.handlers.injectionPoint.AtResolver
 import com.demonwav.mcdev.platform.mixin.handlers.injectionPoint.InjectionPoint
 import com.demonwav.mcdev.platform.mixin.inspection.MixinInspection
@@ -38,13 +40,24 @@ class DiscouragedShiftInspection : MixinInspection() {
             if (!annotation.hasQualifiedName(MixinConstants.Annotations.AT)) {
                 return
             }
+            val injectorAnnotation = AtResolver.findInjectorAnnotation(annotation) ?: return
+            val injector = MixinAnnotationHandler.forMixinAnnotation(injectorAnnotation, holder.project) as? InjectorAnnotationHandler
+                ?: return
             val atValue = annotation.findDeclaredAttributeValue("value") ?: return
             val atCode = atValue.constantStringValue ?: return
             val shift = AtResolver.getShift(annotation)
-            if (InjectionPoint.byAtCode(atCode)?.isShiftDiscouraged(shift) == true) {
+            if (isShiftDiscouraged(shift, injector, atCode)) {
                 val shiftElement = annotation.findDeclaredAttributeValue("shift") ?: return
                 holder.registerProblem(shiftElement, "Shifting like this is discouraged because it's brittle")
             }
         }
     }
+
+    private fun isShiftDiscouraged(shift: Int, injector: InjectorAnnotationHandler, atCode: String): Boolean {
+        if (injector.isShiftAlwaysDiscouraged) {
+            return shift != 0
+        }
+
+        return InjectionPoint.byAtCode(atCode)?.isShiftDiscouraged(shift) == true
+    }
 }