[hoanle0126]

Moved from appium/appium-uiautomator2-server#800 for appium/appium-uiautomator2-server#686.

Cause

In SendKeysToElement.setText, text.endsWith("\\n") checks for a trailing literal two-character sequence \n ('\\' followed by 'n'). However, text.replaceFirst("\\n$", "") passes \n$ as a regular expression to String.replaceFirst, which matches an actual LF character (0x0A) rather than the literal \n sequence. As a result, the trailing \n characters remain in text when element.setText(text) is called, while pressEnter is also set to true.

Using text.replaceFirst("\\\\n$", "") escapes the backslash for the regex engine so the trailing literal \n sequence matched by text.endsWith("\\n") is stripped before element.setText(text) and getUiDevice().pressEnter() are executed.

Before / After Reproduction (appium/appium-uiautomator2-server#686 via Java client)

• Environment: Appium 2 with uiautomator2 driver, Java client (io.appium:java-client), target EditText element.
• Java client call:

  WebElement input = driver.findElement(AppiumBy.id("io.appium.android.apis:id/edit"));
  input.sendKeys("aa\\n");

• Before this change:
  • text.endsWith("\\n") evaluates to true (pressEnter = true).
  • text.replaceFirst("\\n$", "") does not match literal \n, leaving text as "aa\\n".
  • element.setText("aa\\n") sets the literal text aa\n into the EditText field, and getUiDevice().pressEnter() is then invoked on top of that.
• After this change:
  • text.replaceFirst("\\\\n$", "") strips the trailing literal \n, leaving text as "aa".
  • element.setText("aa") sets aa into the EditText field, and getUiDevice().pressEnter() sends the Enter key event.
• Actual LF ("aa\n") and append paths (replace=false or replace=null):
  • When model.text ends with an actual LF ("aa\n"), text.endsWith("\\n") is false, so text is passed unchanged ("aa\n") to element.setText without triggering an extra getUiDevice().pressEnter().
  • When model.replace is false or omitted (null), text has its trailing "\\n" stripped first ("aa"), is appended to currentText ("existing_aa"), written via element.setText("existing_aa"), and followed by getUiDevice().pressEnter().

Unit Test Verification (Before vs. After)

Test command:

npm run test:android --workspace appium-uiautomator2-server
# (runs ./gradlew :vendor-xpath2:jar && ./gradlew testServerDebugUnitTest)

• Before fix (text.replaceFirst("\\n$", "")):

  JUnit version 4.13.2
  ..E.E.E.E.
  There were 4 failures:
  1) shouldStripTrailingEscapedNewlineWhenAppendingWithReplaceOmitted(io.appium.uiautomator2.handler.SendKeysToElementTests)
  org.junit.ComparisonFailure: expected:<existing_aa[]> but was:<existing_aa[\n]>
  2) shouldStripTrailingEscapedNewlineAndPressEnter(io.appium.uiautomator2.handler.SendKeysToElementTests)
  org.junit.ComparisonFailure: expected:<aa[]> but was:<aa[\n]>
  3) shouldOnlyStripTrailingEscapedNewlineWhenMultiplePresent(io.appium.uiautomator2.handler.SendKeysToElementTests)
  org.junit.ComparisonFailure: expected:<aa\nbb[]> but was:<aa\nbb[\n]>
  4) shouldStripTrailingEscapedNewlineWhenAppendingWithReplaceFalse(io.appium.uiautomator2.handler.SendKeysToElementTests)
  org.junit.ComparisonFailure: expected:<existing_aa[]> but was:<existing_aa[\n]>
  
  FAILURES!!!
  Tests run: 6,  Failures: 4
  

• After fix (text.replaceFirst("\\\\n$", "")):

  JUnit version 4.13.2
  ......
  OK (6 tests)