[GR-17457] Fix Enumerable#inject edge case usage with arrays

PullRequest: truffleruby/3262

Author: bjfish

spec/ruby/core/enumerable/shared/inject.rb

@@ -17,7 +17,8 @@
   end
 
   it "ignores the block if two arguments" do
-    EnumerableSpecs::Numerous.new(1, 2, 3).send(@method, 10, :-){ raise "we never get here"}.should == 4
+    EnumerableSpecs::Numerous.new(1, 2, 3).send(@method, 10, :-) { raise "we never get here"}.should == 4
+    [].send(@method, 3, :+) { raise "we never get here"}.should == 3
   end
 
   it "can take a symbol argument" do

src/main/java/org/truffleruby/core/array/ArrayNodes.java

@@ -1335,7 +1335,7 @@ public abstract static class InjectNode extends YieldingCoreMethodNode {
 
         @Child private DispatchNode dispatch = DispatchNode.create(PUBLIC);
 
-        // With block
+        // Uses block
 
         @Specialization(guards = { "isEmptyArray(array)", "wasProvided(initialOrSymbol)" })
         @ReportPolymorphism.Exclude
@@ -1392,15 +1392,7 @@ public Object injectBlockHelper(ArrayStoreLibrary stores, RubyArray array,
             return accumulator;
         }
 
-        // With Symbol
-
-        @Specialization(
-                guards = {
-                        "isEmptyArray(array)",
-                        "wasProvided(initialOrSymbol)" })
-        protected Object injectSymbolEmptyArray(RubyArray array, Object initialOrSymbol, RubySymbol symbol, Nil block) {
-            return initialOrSymbol;
-        }
+        // Uses Symbol
 
         @Specialization(guards = { "isEmptyArray(array)" })
         protected Object injectSymbolEmptyArrayNoInitial(
@@ -1410,11 +1402,18 @@ protected Object injectSymbolEmptyArrayNoInitial(
 
         @Specialization(
                 guards = {
-                        "!isEmptyArray(array)",
-                        "wasProvided(initialOrSymbol)" },
+                        "isEmptyArray(array)",
+                        "wasProvided(initialOrSymbol)" })
+        protected Object injectSymbolEmptyArray(
+                RubyArray array, Object initialOrSymbol, RubySymbol symbol, Object maybeBlock) {
+            return initialOrSymbol;
+        }
+
+        @Specialization(
+                guards = { "!isEmptyArray(array)" },
                 limit = "storageStrategyLimit()")
-        protected Object injectSymbolWithInitial(
-                VirtualFrame frame, RubyArray array, Object initialOrSymbol, RubySymbol symbol, Nil block,
+        protected Object injectSymbolNoInitial(
+                VirtualFrame frame, RubyArray array, RubySymbol initialOrSymbol, NotProvided symbol, Nil block,
                 @Bind("array.store") Object store,
                 @CachedLibrary("store") ArrayStoreLibrary stores,
                 @Cached IntValueProfile arraySizeProfile,
@@ -1423,20 +1422,22 @@ protected Object injectSymbolWithInitial(
             return injectSymbolHelper(
                     frame,
                     array,
-                    toJavaString.executeToJavaString(symbol),
+                    toJavaString.executeToJavaString(initialOrSymbol),
                     stores,
                     store,
-                    initialOrSymbol,
-                    0,
+                    stores.read(store, 0),
+                    1,
                     arraySizeProfile,
                     loopProfile);
         }
 
         @Specialization(
-                guards = { "!isEmptyArray(array)" },
+                guards = {
+                        "!isEmptyArray(array)",
+                        "wasProvided(initialOrSymbol)" },
                 limit = "storageStrategyLimit()")
-        protected Object injectSymbolNoInitial(
-                VirtualFrame frame, RubyArray array, RubySymbol initialOrSymbol, NotProvided symbol, Nil block,
+        protected Object injectSymbolWithInitial(
+                VirtualFrame frame, RubyArray array, Object initialOrSymbol, RubySymbol symbol, Object block,
                 @Bind("array.store") Object store,
                 @CachedLibrary("store") ArrayStoreLibrary stores,
                 @Cached IntValueProfile arraySizeProfile,
@@ -1445,15 +1446,17 @@ protected Object injectSymbolNoInitial(
             return injectSymbolHelper(
                     frame,
                     array,
-                    toJavaString.executeToJavaString(initialOrSymbol),
+                    toJavaString.executeToJavaString(symbol),
                     stores,
                     store,
-                    stores.read(store, 0),
-                    1,
+                    initialOrSymbol,
+                    0,
                     arraySizeProfile,
                     loopProfile);
         }
 
+        // No Symbol or Block
+
         @Specialization
         protected Object injectNoSymbolNonEmptyArrayNoInitial(
                 RubyArray array, NotProvided initialOrSymbol, NotProvided symbol, Nil block) {