Attempting to improve the JShell behavior w.r.t. ELVD; test by biboudis.

Author: lahodaj

src/jdk.jshell/share/classes/jdk/internal/jshell/tool/JShellTool.java

@@ -3104,7 +3104,11 @@ private boolean cmdList(String arg) {
                 cmdout.println();
                 hasOutput[0] = true;
             }
-            cmdout.printf("%4s : %s\n", sn.id(), sn.source().replace("\n", "\n       "));
+            if (sn.subKind() == Snippet.SubKind.VAR_BINDING_SUBKIND) {
+                cmdout.printf("%4s : %s\n", sn.id(), messageFormat("jshell.msg.list.binding", ((VarSnippet) sn).name(), sn.source().replace("\n", "\n       ")));
+            } else {
+                cmdout.printf("%4s : %s\n", sn.id(), sn.source().replace("\n", "\n       "));
+            }
         });
         return true;
     }
@@ -3965,7 +3969,7 @@ private void displayDeclarationAndValue() {
                     custom(FormatCase.VARDECL, vk.name(), vk.typeName());
                     break;
                 }
-                case VAR_DECLARATION_WITH_INITIALIZER_SUBKIND: {
+                case VAR_DECLARATION_WITH_INITIALIZER_SUBKIND, VAR_BINDING_SUBKIND: {
                     VarSnippet vk = (VarSnippet) sn;
                     custom(FormatCase.VARINIT, vk.name(), vk.typeName());
                     break;

src/jdk.jshell/share/classes/jdk/internal/jshell/tool/resources/l10n.properties

@@ -194,6 +194,10 @@ jshell.console.erroneous = \nIncomplete or erroneous. A single valid expression
 jshell.console.exprstmt = \nA single valid expression or statement must precede Shift+Tab m.
 jshell.console.empty = \nEmpty entry. A single valid expression or statement must precede Shift+Tab m.
 
+#{0}: the name of the binding
+#{1}: the full snippet
+jshell.msg.list.binding = binding {0} in {1}
+
 jshell.fix.wrong.shortcut =\
 Unexpected character after Shift+Tab.\n\
 Use "i" for auto-import, "v" for variable creation, or "m" for method creation.\n\

src/jdk.jshell/share/classes/jdk/jshell/Eval.java

@@ -266,7 +266,6 @@ private List<Snippet> processEnhancedVarDecl(String userSource, Tree unitTree, S
         // short circuit since inference is expensive
         boolean hasAnyVars = false;
         for (JCTree.JCBindingPattern bp : patternBindings) {
-            String bindingName = bp.getVariable().getName().toString();
             Tree bindingTypeTree = bp.getVariable().getType();
             if (bindingTypeTree.getKind() == Tree.Kind.VAR_TYPE) {
                 hasAnyVars = true;
@@ -289,31 +288,49 @@ private List<Snippet> processEnhancedVarDecl(String userSource, Tree unitTree, S
             bindings = ExpressionToTypeInfo.enhancedLocalVariableDeclInferBindings(userSource, state, false);
         }
 
-        Wrap guts = Wrap.enhancedLocalVariableDeclWrap(compileSource, bindings);
-        DiagList dl = trialCompile(guts);
+        if (bindings.isEmpty()) {
+            Wrap guts = Wrap.simpleWrap(compileSource);
+            return List.of(new StatementSnippet(state.keyMap.keyForStatement(), userSource, guts));
+        }
+
+        List<Snippet> result = new ArrayList<>();
+
+        Wrap primaryGuts = Wrap.primaryEnhancedLocalVariableDeclWrap(compileSource, bindings);
+        DiagList dl = trialCompile(primaryGuts);
         if (dl.hasErrors()){
             return compileFailResult(dl, userSource, kindOfTree(unitTree));
         }
         TreeDependencyScanner tds = new TreeDependencyScanner();
         tds.scan(unitTree);
 
-        BindingInfo primary = bindings.getFirst();
-        Set<String> additionalStaticImportNames =
-                bindings.stream().skip(1).map(BindingInfo::bindingName).collect(Collectors.toSet());
+        BindingInfo primaryBinding = bindings.getFirst();
 
-        Snippet snip = new VarSnippet(
-                state.keyMap.keyForVariable((primary.bindingName())),
+        VarSnippet primarySnippet = new VarSnippet(
+                state.keyMap.keyForVariable((primaryBinding.bindingName())),
                 userSource,
-                guts,
-                primary.bindingName(),
-                primary.bindingName(),
-                SubKind.VAR_DECLARATION_WITH_INITIALIZER_SUBKIND,
-                primary.displayTypeName(),
-                primary.hasEnhancedType() ? primary.fullTypeName() : null,
-                additionalStaticImportNames,
-                tds.declareReferences(), null);
-
-        return singletonList(snip);
+                primaryGuts,
+                primaryBinding.bindingName(),
+                primaryBinding.bindingName(),
+                SubKind.VAR_BINDING_SUBKIND,
+                primaryBinding.displayTypeName(),
+                primaryBinding.hasEnhancedType() ? primaryBinding.fullTypeName() : null,
+                Set.of(),
+                tds.declareReferences(), null, List.of());
+        result.add(primarySnippet);
+        bindings.stream().skip(1).map(bi -> new VarSnippet(
+                state.keyMap.keyForVariable((bi.bindingName())),
+                userSource,
+                Wrap.secondaryEnhancedLocalVariableDeclWrap(compileSource, bi),
+                bi.bindingName(),
+                bi.bindingName(),
+                SubKind.VAR_BINDING_SUBKIND,
+                bi.displayTypeName(),
+                bi.hasEnhancedType() ? bi.fullTypeName() : null,
+                Set.of(),
+                tds.declareReferences(), null, List.of(new Snippet.ExtraImport(primarySnippet, bi.bindingName()))))
+                .forEach(result::add);
+
+        return result;
     }
     // where
         static void gatherBindings(JCTree pattern, Consumer<JCTree.JCBindingPattern> sink) {
@@ -505,7 +522,7 @@ private List<Snippet> processVariables(String userSource, List<? extends Tree> u
             DiagList modDiag = modifierDiagnostics(vt.getModifiers(), dis, true);
             Snippet snip = new VarSnippet(state.keyMap.keyForVariable(name), userSource, guts,
                     name, fieldName, subkind, displayType, hasEnhancedType ? fullTypeName : null, additionalStaticImportNames,
-                    tds.declareReferences(), modDiag);
+                    tds.declareReferences(), modDiag, List.of());
             snippets.add(snip);
         }
         return snippets;
@@ -766,7 +783,7 @@ private List<Snippet> processExpression(String userSource, Tree tree, String com
                 Collection<String> declareReferences = null; //TODO
                 snip = new VarSnippet(state.keyMap.keyForVariable(name), userSource, guts,
                         name, name, SubKind.TEMP_VAR_EXPRESSION_SUBKIND, displayTypeName, fullTypeName,
-                        additionalStaticImportNames, declareReferences, null);
+                        additionalStaticImportNames, declareReferences, null, List.of());
             } else {
                 guts = Wrap.methodReturnWrap(compileSource);
                 snip = new ExpressionSnippet(state.keyMap.keyForExpression(name, typeName), userSource, guts,

src/jdk.jshell/share/classes/jdk/jshell/OuterWrapMap.java

@@ -71,13 +71,14 @@ private CompoundWrap wrappedInClass(String className, String imports, List<Wrap>
         return new CompoundWrap(elems.toArray());
     }
 
-    OuterWrap wrapInClass(Set<Key> except, Collection<Snippet> plus,
+    OuterWrap wrapInClass(Set<Key> except, Collection<Snippet> plus, List<String> additionalExtraImports,
             List<Snippet> snippets, List<Wrap> wraps) {
         List<String> extraImports =
                 plus.stream()
                     .map(psi -> psi.importLine(state))
                     .toList();
-        String imports = state.maps.packageAndImportsExcept(except, extraImports);
+        String imports = state.maps.packageAndImportsExcept(except, extraImports) +
+                         additionalExtraImports.stream().collect(Collectors.joining("\n", "\n", ""));
         // className is unique to the set of snippets and their version (seq)
         String className = REPL_CLASS_PREFIX + snippets.stream()
                 .sorted((sn1, sn2) -> sn1.key().index() - sn2.key().index())

src/jdk.jshell/share/classes/jdk/jshell/Snippet.java

@@ -279,6 +279,13 @@ public enum SubKind {
          */
         VAR_DECLARATION_WITH_INITIALIZER_SUBKIND(Kind.VAR, true, true),
 
+        /**
+         * An binding variable.
+         * {@code SubKind} of {@link Kind#VAR}.
+         * @since 27
+         */
+        VAR_BINDING_SUBKIND(Kind.VAR, true, true),
+
         /**
          * An expression whose value has been stored in a temporary variable. A
          * {@code SubKind} of {@link Kind#VAR}.
@@ -768,4 +775,9 @@ boolean isExecutable() {
         return subkind.isExecutable();
     }
 
+    List<ExtraImport> getExtraImports() {
+        return List.of();
+    }
+
+    record ExtraImport(Snippet from, String name) {}
 }

src/jdk.jshell/share/classes/jdk/jshell/Unit.java

@@ -179,7 +179,10 @@ void setWrap(Collection<Unit> exceptUnit, Collection<Unit> plusUnfiltered) {
                     .map(u -> u.activeGuts)
                     .toList();
             // Set the outer wrap for this snippet
-            si.setOuterWrap(state.outerMap.wrapInClass(except, plus, snippets, wraps));
+            List<String> additionalExtraImports = units.stream().flatMap(u -> u.snippet().getExtraImports().stream())
+                    .map(ei -> "import static " + ei.from().classFullName() + "." + ei.name() + "_;")
+                    .toList();
+            si.setOuterWrap(state.outerMap.wrapInClass(except, plus, additionalExtraImports, snippets, wraps));
             state.debug(DBG_WRAP, "++setWrap() %s\n%s\n",
                     si, si.outerWrap().wrapped());
         }

src/jdk.jshell/share/classes/jdk/jshell/VarSnippet.java

@@ -26,6 +26,7 @@
 package jdk.jshell;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Set;
 import jdk.jshell.Key.VarKey;
 
@@ -61,16 +62,19 @@ public class VarSnippet extends DeclarationSnippet {
 
     final String fieldName;
 
+    private final List<ExtraImport> extraImports;
+
      VarSnippet(VarKey key, String userSource, Wrap guts,
             String name, String fieldName, SubKind subkind, String typeName, String fullTypeName,
             Set<String> additionalStaticImportNames, Collection<String> declareReferences,
-            DiagList syntheticDiags) {
+            DiagList syntheticDiags, List<ExtraImport> extraImports) {
         super(key, userSource, guts, name, subkind, null, declareReferences,
                 null, syntheticDiags);
         this.typeName = typeName;
         this.fullTypeName = fullTypeName;
         this.additionalStaticImportNames = additionalStaticImportNames;
         this.fieldName = fieldName;
+        this.extraImports = extraImports;
     }
 
     String fieldName() {
@@ -92,4 +96,9 @@ String importLine(JShell state) {
         return imports.toString();
     }
 
+    @Override
+    List<ExtraImport> getExtraImports() {
+        return extraImports;
+    }
+
 }

src/jdk.jshell/share/classes/jdk/jshell/Wrap.java

@@ -184,15 +184,17 @@ private static int countLines(String s, int from, int toEx) {
         return cnt;
     }
 
-    public static Wrap enhancedLocalVariableDeclWrap(String compileSource, List<BindingInfo> bindings) {
+    public static Wrap primaryEnhancedLocalVariableDeclWrap(String compileSource, List<BindingInfo> bindings) {
         List<Wrap> members = new ArrayList<>();
         List<String> methodsForAssigningBindings = new ArrayList<>(bindings.size());
 
         // public static Type bindingName;
+        String suffix = "";
         for (var b : bindings) {
             members.add(new CompoundWrap(
-                    "     public static\n    ", b.declareTypeName(), " ", b.bindingName(), ";\n"
+                    "     public static\n    ", b.declareTypeName(), " ", b.bindingName() + suffix, ";\n"
             ));
+            suffix = "_";
         }
 
         // public static Type $setBindingMethodName(Type $v) { return bindingName = $v; }
@@ -202,8 +204,8 @@ public static Wrap enhancedLocalVariableDeclWrap(String compileSource, List<Bind
             String methodName = setBindingMethodName + "$" + i;
             methodsForAssigningBindings.add(methodName);
             members.add(new CompoundWrap(
-                    "   private static ", bi.declareTypeName(), " ", methodName, "(", bi.declareTypeName(), " $v", ") { \n",
-                         "        return ", bi.bindingName(), " = $v", ";\n",
+                    "   private static ", bi.declareTypeName(), " ", methodName, "(", bi.declareTypeName(), " " + bi.bindingName() + "__", ") { \n",
+                         "        return ", bi.bindingName() + (i == 0 ? "" : "_"), " = " + bi.bindingName() + "__", ";\n",
                          "}\n"));
         }
 
@@ -228,6 +230,19 @@ public static Wrap enhancedLocalVariableDeclWrap(String compileSource, List<Bind
         return new CompoundWrap(members.toArray());
     }
 
+    public static Wrap secondaryEnhancedLocalVariableDeclWrap(String compileSource, BindingInfo binding) {
+        List<Wrap> members = new ArrayList<>();
+
+        // public static Type bindingName;
+        members.add(new CompoundWrap(
+                "     public static\n    ", binding.declareTypeName(), " ", binding.bindingName(), ";\n"
+        ));
+
+        members.add(new DoitMethodWrap(new CompoundWrap(" return " + binding.bindingName() + " = " + binding.bindingName() + "_;")));
+
+        return new CompoundWrap(members.toArray());
+    }
+
     public static final class Range {
         final int begin;
         final int end; // exclusive