added PY-1445 Inspection to highlight docstrings using single quotes

python/src/com/jetbrains/python/PyBundle.properties

@@ -69,6 +69,9 @@ QFIX.unresolved.reference.add.future=Add 'from __future__ import with_statement'
 # RemoveUnnecessaryBackslashQuickFix
 QFIX.remove.unnecessary.backslash=Remove unnecessary backslash in expression
 
+# ConvertDocstringQuickFix
+QFIX.convert.single.quoted.docstring=Convert docstring to the triple double-quoted string form
+
 # Intentions: INTN
 INTN.Family.convert.import.unqualify=Convert 'import module' to 'from module import'
 INTN.Family.convert.import.qualify=Convert 'from module import' to 'import module'
@@ -357,6 +360,10 @@ INSP.NAME.compatibility=Code compatibility inspection
 # PyUnnecessaryBackslashInspection
 INSP.NAME.unnecessary.backslash=Unnecessary backslash
 
+# PySingleQuotedDocstringInspection
+INSP.NAME.single.quoted.docstring=Single quoted docstring
+
+
 # Refactoring
 # introduce
 refactoring.introduce.name.error=Incorrect name

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

@@ -0,0 +1,53 @@
+package com.jetbrains.python.actions;
+
+import com.intellij.codeInspection.LocalQuickFix;
+import com.intellij.codeInspection.ProblemDescriptor;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
+import com.jetbrains.python.PyBundle;
+import com.jetbrains.python.psi.LanguageLevel;
+import com.jetbrains.python.psi.PyElementGenerator;
+import com.jetbrains.python.psi.PyExpressionStatement;
+import com.jetbrains.python.psi.PyStringLiteralExpression;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: catherine
+ *
+ * QuickFix to convert docstrings to the common form according to PEP-257
+ * For consistency, always use """triple double quotes""" around docstrings.
+ */
+public class ConvertDocstringQuickFix implements LocalQuickFix {
+
+  public ConvertDocstringQuickFix() {
+  }
+
+  @NotNull
+  public String getName() {
+    return PyBundle.message("QFIX.convert.single.quoted.docstring");
+  }
+
+  @NotNull
+  public String getFamilyName() {
+    return PyBundle.message("INSP.GROUP.python");
+  }
+
+  public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+    PsiElement expression = descriptor.getPsiElement();
+    if (expression instanceof PyStringLiteralExpression) {
+      PyElementGenerator elementGenerator = PyElementGenerator.getInstance(project);
+
+      String content = expression.getText();
+      if (content.startsWith("'''") ) {
+        content = content.substring(3, content.length()-3);
+      } else {
+        content = content.substring(1, content.length()-1);
+      }
+
+      PyStringLiteralExpression newString = (PyStringLiteralExpression)elementGenerator.createFromText(LanguageLevel.forElement(expression),
+                                PyExpressionStatement.class,"\"\"\"" + content + "\"\"\"").getExpression();
+      expression.replace(newString);
+    }
+  }
+
+}

python/src/com/jetbrains/python/inspections/PySingleQuotedDocstringInspection.java

@@ -0,0 +1,50 @@
+package com.jetbrains.python.inspections;
+
+import com.intellij.codeInspection.ProblemsHolder;
+import com.intellij.psi.PsiElementVisitor;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.jetbrains.python.PyBundle;
+import com.jetbrains.python.actions.ConvertDocstringQuickFix;
+import com.jetbrains.python.psi.PyDocStringOwner;
+import com.jetbrains.python.psi.PyStringLiteralExpression;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: catherine
+ *
+ * Inspection to detect docstrings not using triple double-quoted string
+ */
+public class PySingleQuotedDocstringInspection extends PyInspection {
+
+  @Nls
+  @NotNull
+  @Override
+  public String getDisplayName() {
+    return PyBundle.message("INSP.NAME.single.quoted.docstring");
+  }
+
+  @NotNull
+  @Override
+  public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder, boolean isOnTheFly) {
+    return new Visitor(holder);
+  }
+
+  private static class Visitor extends PyInspectionVisitor {
+    public Visitor(final ProblemsHolder holder) {
+      super(holder);
+    }
+
+    @Override
+    public void visitPyStringLiteralExpression(final PyStringLiteralExpression string) {
+      String stringText = string.getText();
+      final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(string, PyDocStringOwner.class);
+      if (docStringOwner != null) {
+        if (docStringOwner.getDocStringExpression() == string)  {
+          if (!stringText.startsWith("\"\"\"") && !stringText.endsWith("\"\"\""))
+            registerProblem(string, "Triple double-quoted strings should be used for docstrings.", new ConvertDocstringQuickFix());
+        }
+      }
+    }
+  }
+}

python/src/com/jetbrains/python/inspections/PythonInspectionToolProvider.java

@@ -55,6 +55,7 @@ public class PythonInspectionToolProvider implements InspectionToolProvider {
       PyCompatibilityInspection.class,
       PyListCreationInspection.class,
       PyUnnecessaryBackslashInspection.class,
+      PySingleQuotedDocstringInspection.class,
     };
   }
 }

python/testData/inspections/ConvertSingleQuotedDocstring.py

@@ -0,0 +1,4 @@
+def foo():
+  <warning descr="Triple double-quoted strings should be used for docstrings."><caret>'''foo first line docstring
+  second line of docstring'''</warning>
+  pass

python/testData/inspections/ConvertSingleQuotedDocstring_after.py

@@ -0,0 +1,4 @@
+def foo():
+  """foo first line docstring
+  second line of docstring"""
+  pass

python/testData/inspections/PySingleQuotedDocstringInspection/test.py

@@ -0,0 +1,17 @@
+<warning descr="Triple double-quoted strings should be used for docstrings.">'''package docstring'''</warning>
+
+def foo():
+  <warning descr="Triple double-quoted strings should be used for docstrings.">"foo docstring"</warning>
+  pass
+
+class Klass:
+  <warning descr="Triple double-quoted strings should be used for docstrings.">'class docstring\
+  second line'</warning>
+  pass
+
+def bar():
+  """ bar docstring """
+  pass
+
+a = '''some string'''
+'''another string'''

python/testSrc/com/jetbrains/python/PyQuickFixTest.java

@@ -220,6 +220,11 @@ public class PyQuickFixTest extends PyLightFixtureTestCase {
                      PyBundle.message("QFIX.list.creation"), true, true);
   }
 
+  public void testConvertSingleQuotedDocstring() {                      //PY-1445
+    doInspectionTest("ConvertSingleQuotedDocstring.py", PySingleQuotedDocstringInspection.class,
+                     PyBundle.message("QFIX.convert.single.quoted.docstring"), true, true);
+  }
+
   public void testUnnecessaryBackslash() {
     String[] testFiles = new String[]{"UnnecessaryBackslash.py"};
     myFixture.enableInspections(PyUnnecessaryBackslashInspection.class);

python/testSrc/com/jetbrains/python/PythonInspectionsTest.java

@@ -308,4 +308,8 @@ public class PythonInspectionsTest extends PyLightFixtureTestCase {
     setLanguageLevel(LanguageLevel.PYTHON27);
     doHighlightingTest(PyUnnecessaryBackslashInspection.class);
   }
+
+  public void testPySingleQuotedDocstringInspection() {    //PY-1445
+    doHighlightingTest(PySingleQuotedDocstringInspection.class);
+  }
 }