IDEA-92081 Reformat causes syntax error when "Ensure margin not exceeded"

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

@@ -1,6 +1,10 @@
 package com.jetbrains.python.formatter;
 
+import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.editor.GenericLineWrapPositionStrategy;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.util.text.CharArrayUtil;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * @author yole
@@ -22,4 +26,22 @@ public class PyLineWrapPositionStrategy extends GenericLineWrapPositionStrategy
     // Symbols to wrap before
     addRule(new Rule('.', WrapCondition.BEFORE));
   }
+
+  @Override
+  protected boolean canUseOffset(@NotNull Document document, int offset, boolean virtual) {
+    if (virtual) {
+      return true;
+    }
+    CharSequence text = document.getCharsSequence();
+    char c = text.charAt(offset);
+    if (!StringUtil.isWhiteSpace(c)) {
+      return true;
+    }
+
+    int i = CharArrayUtil.shiftBackward(text, offset, " \t");
+    if (i < 2) {
+      return true;
+    }
+    return text.charAt(i - 2) != 'd' || text.charAt(i - 1) != 'e' || text.charAt(i) != 'f';
+  }
 }

python/testData/formatter/wrapDefinitionWithLongLine.py

@@ -0,0 +1,2 @@
+def my_function_name_which_is_rather_long:
+    pass

python/testData/formatter/wrapDefinitionWithLongLine_after.py

@@ -0,0 +1,2 @@
+def my_function_name_which_is_rather_long:
+    pass

python/testSrc/com/jetbrains/python/PyFormatterTest.java

@@ -207,6 +207,12 @@ public class PyFormatterTest extends PyTestCase {
     assertEquals(expected, reformatted.getText());
   }
 
+  public void testWrapDefinitionWithLongLine() { // IDEA-92081
+    settings().RIGHT_MARGIN = 30;
+    settings().WRAP_LONG_LINES = true;
+    doTest();
+  }
+  
   private void doTest() {
     myFixture.configureByFile("formatter/" + getTestName(true) + ".py");
     ApplicationManager.getApplication().runWriteAction(new Runnable() {