fixed PY-8581 Fill Paragraph should not corrupt indentation

PY-8937 fill paragraph works wrong on simple strings

python/src/com/jetbrains/python/actions/PyFillParagraphHandler.java

@@ -5,9 +5,12 @@ import com.intellij.openapi.util.Pair;
 import com.intellij.psi.PsiComment;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
+import com.intellij.psi.PsiWhiteSpace;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.jetbrains.python.PythonStringUtil;
+import com.jetbrains.python.psi.PyDocStringOwner;
 import com.jetbrains.python.psi.PyFile;
+import com.jetbrains.python.psi.PyStatementList;
 import com.jetbrains.python.psi.PyStringLiteralExpression;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -24,7 +27,19 @@ public class PyFillParagraphHandler extends ParagraphFillHandler {
     if (stringLiteralExpression != null) {
       final Pair<String,String> quotes =
         PythonStringUtil.getQuotes(stringLiteralExpression.getText());
-      return quotes != null? quotes.getFirst()+"\n" : "\"\n";
+      final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(stringLiteralExpression, PyDocStringOwner.class);
+      if (docStringOwner != null && stringLiteralExpression.equals(docStringOwner.getDocStringExpression())) {
+        final PyStatementList statementList = PsiTreeUtil.getParentOfType(stringLiteralExpression, PyStatementList.class);
+        final PsiElement whiteSpace = statementList.getPrevSibling();
+        String indent;
+        if (whiteSpace instanceof PsiWhiteSpace)
+          indent = whiteSpace.getText();
+        else
+          indent = "\n";
+        return quotes != null? quotes.getFirst()+ indent : "\"" + indent;
+      }
+      else
+        return quotes != null? quotes.getFirst() : "\"";
     }
     return element instanceof PsiComment? "# " : "";
   }
@@ -37,7 +52,19 @@ public class PyFillParagraphHandler extends ParagraphFillHandler {
     if (stringLiteralExpression != null) {
       final Pair<String,String> quotes =
         PythonStringUtil.getQuotes(stringLiteralExpression.getText());
-      return quotes != null? "\n" + quotes.getSecond() : "\n\"";
+      final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(stringLiteralExpression, PyDocStringOwner.class);
+      if (docStringOwner != null && stringLiteralExpression.equals(docStringOwner.getDocStringExpression())) {
+        final PyStatementList statementList = PsiTreeUtil.getParentOfType(stringLiteralExpression, PyStatementList.class);
+        final PsiElement whiteSpace = statementList.getPrevSibling();
+        String indent;
+        if (whiteSpace instanceof PsiWhiteSpace)
+          indent = whiteSpace.getText();
+        else
+          indent = "\n";
+        return quotes != null? indent + quotes.getSecond() : indent + "\"";
+      }
+      else
+        return quotes != null? quotes.getSecond() : "\"";
     }
     return "";
   }

python/testData/fillParagraph/docstring.py

@@ -0,0 +1,6 @@
+__author__ = 'ktisha'
+
+def foo():
+	"""
+	This is my docstring. <caret>There are many like it, but this one mine. My docstring is my best friend. it is my life. I must master it as I must master my life.
+	"""

python/testData/fillParagraph/docstring_after.py

@@ -0,0 +1,7 @@
+__author__ = 'ktisha'
+
+def foo():
+	"""
+	This is my docstring. There are many like it, but this one mine. My docstring is my best friend. it is my life. I
+	must master it as I must master my life.
+	"""

python/testData/fillParagraph/string.py

@@ -0,0 +1 @@
+p = "my new <caret>string blah blah blah ;j;dsjv sd;fj;dsjf;ds js;djgf ;jsg s;dgj; sjd;gj sd;gj ;sjg;j asdl j;sjdg; jasdgl j;sldjg ;jsd;gj "

python/testData/fillParagraph/string_after.py

@@ -0,0 +1,2 @@
+p = "my new string blah blah blah ;j;dsjv sd;fj;dsjf;ds js;djgf ;jsg s;dgj; sjd;gj sd;gj ;sjg;j asdl j;sjdg; jasdgl " \
+    "j;sldjg ;jsd;gj "

python/testSrc/com/jetbrains/python/PyFillParagraphTest.java

@@ -0,0 +1,37 @@
+package com.jetbrains.python;
+
+import com.intellij.codeInsight.editorActions.fillParagraph.FillParagraphAction;
+import com.intellij.ide.DataManager;
+import com.intellij.openapi.actionSystem.ActionManager;
+import com.intellij.openapi.actionSystem.AnActionEvent;
+import com.intellij.openapi.command.CommandProcessor;
+import com.jetbrains.python.fixtures.PyTestCase;
+
+/**
+ * User : ktisha
+ */
+public class PyFillParagraphTest extends PyTestCase {
+
+  public void testDocstring() {
+    doTest();
+  }
+
+  public void testString() {
+    doTest();
+  }
+
+  private void doTest() {
+    String baseName = "/fillParagraph/" + getTestName(true);
+    myFixture.configureByFile(baseName + ".py");
+    CommandProcessor.getInstance().executeCommand(myFixture.getProject(), new Runnable() {
+      @Override
+      public void run() {
+        FillParagraphAction action = new FillParagraphAction();
+        action.actionPerformed(new AnActionEvent(null, DataManager.getInstance().getDataContext(), "",
+                                                 action.getTemplatePresentation(),
+                                                 ActionManager.getInstance(), 0));
+      }
+    }, "", null);
+    myFixture.checkResultByFile(baseName + "_after.py", true);
+  }
+}