PY-12008 Use another type of block for binary expressions

in order to the structure of nested binary expressions during
formatting. For instance, "x and y or z" and "x or y and z" should
be formatted the same regardless of the precedence of individual
operations.

python/src/com/jetbrains/python/formatter/PyBinaryExpressionBlock.java

@@ -0,0 +1,57 @@
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.jetbrains.python.formatter;
+
+import com.intellij.formatting.Alignment;
+import com.intellij.formatting.Indent;
+import com.intellij.formatting.Wrap;
+import com.intellij.lang.ASTNode;
+import com.jetbrains.python.PyElementTypes;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author Mikhail Golubev
+ */
+public class PyBinaryExpressionBlock extends PyBlock {
+
+  private List<ASTNode> myChildrenNodes = new ArrayList<>();
+
+  public PyBinaryExpressionBlock(@Nullable PyBlock parent,
+                                 @NotNull ASTNode node,
+                                 @Nullable Alignment alignment,
+                                 @NotNull Indent indent,
+                                 @Nullable Wrap wrap,
+                                 @NotNull PyBlockContext context) {
+    super(parent, node, alignment, indent, wrap, context);
+    assert node.getElementType() == PyElementTypes.BINARY_EXPRESSION;
+
+    myChildrenNodes = collectChildren();
+  }
+
+  @NotNull
+  private List<ASTNode> collectChildren() {
+    List<ASTNode> result = new ArrayList<>();
+    collectChildren(myNode, result);
+    return result;
+  }
+
+  private void collectChildren(@NotNull ASTNode node, @NotNull List<ASTNode> result) {
+    if (node.getElementType() == PyElementTypes.BINARY_EXPRESSION) {
+      for (ASTNode child : node.getChildren(null)) {
+        collectChildren(child, result);
+      }
+    }
+    else if (node != this) {
+      result.add(node);
+    }
+  }
+
+  @NotNull
+  @Override
+  protected Iterable<ASTNode> getSubBlockNodes() {
+    return myChildrenNodes;
+  }
+}

python/src/com/jetbrains/python/formatter/PyBlock.java

@@ -81,10 +81,23 @@ public class PyBlock implements ASTBlock {
   public static final Key<Boolean> IMPORT_GROUP_BEGIN = Key.create("com.jetbrains.python.formatter.importGroupBegin");
   private static final boolean ALIGN_IF_CONDITION_WITHOUT_PARENTHESES = false;
 
+  @NotNull
+  public static PyBlock createBlock(@Nullable PyBlock parent,
+                                    @NotNull ASTNode node,
+                                    @Nullable Alignment alignment,
+                                    @NotNull Indent indent,
+                                    @Nullable Wrap wrap,
+                                    @NotNull PyBlockContext context) {
+    if (node.getElementType() == PyElementTypes.BINARY_EXPRESSION) {
+      return new PyBinaryExpressionBlock(parent, node, alignment, indent, wrap, context);
+    }
+    return new PyBlock(parent, node, alignment, indent, wrap, context);
+  }
+
   private final PyBlock myParent;
   private final Alignment myAlignment;
   private final Indent myIndent;
-  private final ASTNode myNode;
+  protected final ASTNode myNode;
   private final Wrap myWrap;
   private final PyBlockContext myContext;
   private List<PyBlock> mySubBlocks = null;
@@ -97,12 +110,12 @@ public class PyBlock implements ASTBlock {
   private Wrap myDictWrapping = null;
   private Wrap myFromImportWrapping = null;
 
-  public PyBlock(@Nullable PyBlock parent,
-                 @NotNull ASTNode node,
-                 @Nullable Alignment alignment,
-                 @NotNull Indent indent,
-                 @Nullable Wrap wrap,
-                 @NotNull PyBlockContext context) {
+  protected PyBlock(@Nullable PyBlock parent,
+                    @NotNull ASTNode node,
+                    @Nullable Alignment alignment,
+                    @NotNull Indent indent,
+                    @Nullable Wrap wrap,
+                    @NotNull PyBlockContext context) {
     myParent = parent;
     myAlignment = alignment;
     myIndent = indent;
@@ -163,7 +176,7 @@ public class PyBlock implements ASTBlock {
   @NotNull
   private Map<ASTNode, PyBlock> buildSubBlocks() {
     final Map<ASTNode, PyBlock> blocks = new LinkedHashMap<>();
-    for (ASTNode child = myNode.getFirstChildNode(); child != null; child = child.getTreeNext()) {
+    for (ASTNode child: getSubBlockNodes()) {
 
       final IElementType childType = child.getElementType();
 
@@ -178,6 +191,11 @@ public class PyBlock implements ASTBlock {
     return Collections.unmodifiableMap(blocks);
   }
 
+  @NotNull
+  protected Iterable<ASTNode> getSubBlockNodes() {
+    return Arrays.asList(myNode.getChildren(null));
+  }
+
   @NotNull
   private PyBlock buildSubBlock(@NotNull ASTNode child) {
     final IElementType parentType = myNode.getElementType();
@@ -405,7 +423,7 @@ public class PyBlock implements ASTBlock {
       prev = prev.getTreePrev();
     }
 
-    return new PyBlock(this, child, childAlignment, childIndent, childWrap, myContext);
+    return createBlock(this, child, childAlignment, childIndent, childWrap, myContext);
   }
 
   private static boolean isParenthesisedIfCondition(@NotNull ASTNode node) {

python/src/com/jetbrains/python/formatter/PythonFormattingModelBuilder.java

@@ -51,7 +51,7 @@ public class PythonFormattingModelBuilder implements FormattingModelBuilderEx, C
       printAST(fileNode, 0);
     }
     final PyBlockContext context = new PyBlockContext(settings, createSpacingBuilder(settings), mode);
-    final PyBlock block = new PyBlock(null, element.getNode(), null, Indent.getNoneIndent(), null, context);
+    final PyBlock block = PyBlock.createBlock(null, element.getNode(), null, Indent.getNoneIndent(), null, context);
     if (DUMP_FORMATTING_AST) {
       FormattingModelDumper.dumpFormattingModel(block, 2, System.out);
     }

python/testData/formatter/multilineElifCondition_after.py

@@ -1,5 +1,5 @@
 if foo and \
-   bar == 42:
+        bar == 42:
     pass
 elif foo and \
      bar: