[editor] IDEA-273139 Smart enter should work for host language in single-line injections

GitOrigin-RevId: b7b1c6992b1afa545b96d79bf75ed8a4ea5f3469

java/java-tests/testData/codeInsight/completeStatement/InInjection.java

@@ -0,0 +1,5 @@
+import java.util.regex.Pattern;
+
+public class InInjection {
+  static final Pattern p = Pattern.compile("\\d+<caret>")
+}

java/java-tests/testData/codeInsight/completeStatement/InInjection_after.java

@@ -0,0 +1,5 @@
+import java.util.regex.Pattern;
+
+public class InInjection {
+    static final Pattern p = Pattern.compile("\\d+");
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/CompleteStatementTest.java

@@ -191,6 +191,7 @@ public class CompleteStatementTest extends EditorActionTestCase {
   public void testOverloadedMethodOneOrThree2() { doTest(); }
   public void testOverloadedMethodOneOrThree3() { doTest(); }
   public void testMissingComma() { doTest(); }
+  public void testInInjection() { doTest(); }
 
   private void doTestBracesNextLineStyle() {
     myJavaSettings.BRACE_STYLE = CommonCodeStyleSettings.NEXT_LINE;

platform/lang-impl/src/com/intellij/codeInsight/editorActions/smartEnter/SmartEnterAction.java

@@ -6,6 +6,7 @@ import com.intellij.codeInsight.editorActions.enter.EnterAfterUnmatchedBraceHand
 import com.intellij.codeInsight.lookup.LookupManager;
 import com.intellij.codeInsight.template.impl.TemplateManagerImpl;
 import com.intellij.codeInsight.template.impl.TemplateState;
+import com.intellij.injected.editor.EditorWindow;
 import com.intellij.lang.Language;
 import com.intellij.openapi.actionSystem.CommonDataKeys;
 import com.intellij.openapi.actionSystem.DataContext;
@@ -32,6 +33,10 @@ public class SmartEnterAction extends EditorAction {
   private static class Handler extends EditorWriteActionHandler.ForEachCaret {
     @Override
     public boolean isEnabledForCaret(@NotNull Editor editor, @NotNull Caret caret, DataContext dataContext) {
+      if (editor.isOneLineMode() && editor instanceof EditorWindow) {
+        // One-line injection: prefer for host instead
+        return false;
+      }
       return getEnterHandler().isEnabled(editor, caret, dataContext);
     }