RUBY-18345: Fix YAML scalars content retrieval when template is injected

Now the "get content" routine is made agnostic to its token-type contents
(cherry picked from commit 97c78baa r=IDEA-CR-12697)

(cherry picked from commit 88002d69)

plugins/yaml/src/org/jetbrains/yaml/psi/impl/YAMLBlockScalarImpl.java

 package org.jetbrains.yaml.psi.impl;
 
 import com.intellij.lang.ASTNode;
+import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.yaml.YAMLTokenTypes;
 import org.jetbrains.yaml.YAMLUtil;
 
@@ -43,23 +45,31 @@ public abstract class YAMLBlockScalarImpl extends YAMLScalarImpl {
 
     int thisLineStart = firstEol.getStartOffset() + 1;
     for (ASTNode child = firstEol.getTreeNext(); child != null; child = child.getTreeNext()) {
-      if (child.getElementType() == getContentType()) {
-        assert thisLineStart != -1;
-        result.add(TextRange.create(thisLineStart, child.getTextRange().getEndOffset()).shiftRight(-myStart));
-        thisLineStart = -1;
-      }
-      else if (child.getElementType() == YAMLTokenTypes.INDENT) {
+      final IElementType childType = child.getElementType();
+      final TextRange childRange = child.getTextRange();
+      
+      if (childType == YAMLTokenTypes.INDENT && isEol(child.getTreePrev())) {
         thisLineStart = child.getStartOffset() + Math.min(indent, child.getTextLength());
       }
-      if (child.getElementType() == YAMLTokenTypes.EOL) {
+      else if (childType == YAMLTokenTypes.EOL) {
         if (thisLineStart != -1) {
           result.add(TextRange.create(thisLineStart, child.getStartOffset()).shiftRight(-myStart));
         }
         thisLineStart = child.getStartOffset() + 1;
       }
+      else {
+        if (isEol(child.getTreeNext())) {
+          if (thisLineStart == -1) {
+            Logger.getInstance(YAMLBlockScalarImpl.class).warn("thisLineStart == -1: '" + getText() + "'", new Throwable());
+            continue;
+          }
+          result.add(TextRange.create(thisLineStart, childRange.getEndOffset()).shiftRight(-myStart));
+          thisLineStart = -1;
+        }
+      }
     }
     if (thisLineStart != -1 && thisLineStart != getTextRange().getEndOffset()) {
-          result.add(TextRange.create(thisLineStart, getTextRange().getEndOffset()).shiftRight(-myStart));
+       result.add(TextRange.create(thisLineStart, getTextRange().getEndOffset()).shiftRight(-myStart));
     }
 
     final int lastNonEmpty = ContainerUtil.lastIndexOf(result, range -> range.getLength() != 0);
@@ -79,4 +89,8 @@ public abstract class YAMLBlockScalarImpl extends YAMLScalarImpl {
     }
     return 0;
   }
+  
+  private static boolean isEol(@Nullable ASTNode node) {
+    return node != null && node.getElementType() == YAMLTokenTypes.EOL;
+  }
 }