Display.withCrLf() is producing wrong line breaks on Windows #1557

[Evgeni-Kramerov]

Fixes issue #1557

Changes functions so line breaks display correctly in Windows.

Fixes #1557

[BeckerWdf]

can you please add the test-case provided in #1557

To Reproduce
See Test case

@test
public void testMixedLfAndCrflOnWindows() {
if (!SWT.getPlatform().equals("win32")) {
return;
}

  String act = Display.withCrLf("First Line \n second line \r\n third line");

  assertEquals("First Line \r\n second line \r\n third line", act);

}

[github-actions]

Test Results

   482 files   -  1     482 suites   - 1   8m 18s ⏱️ - 1m 37s
 4 060 tests  - 35   4 037 ✅  - 48   4 💤  - 3  3 ❌ ±0  16 🔥 +16 
16 138 runs   - 35  16 032 ✅  - 48  87 💤  - 3  3 ❌ ±0  16 🔥 +16 

For more details on these failures and errors, see this check.

Results for commit a2045d4. ± Comparison against base commit 435fe7e.

This pull request removes 35 tests.

org.eclipse.swt.graphics.ImageWin32Tests ‑ testImageShouldHaveDimesionAsPerZoomLevel
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testByteArrayTransfer
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testFileTransfer
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testHtmlTransfer
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromCopiedImage
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromImage
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromImageData
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromImageDataFromImage
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testRtfTransfer
org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testTextTransfer
…

[Christopher-Hermann]

There are failing test that are related to this change. Looks like some edge cases which results in out of bounds exception
String index out of range: -1
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.base/java.lang.StringLatin1.charAt(StringLatin1.java:48)
at java.base/java.lang.String.charAt(String.java:1517)
at org.eclipse.swt.widgets.Display.withCrLf(Display.java:5231)
at org.eclipse.swt.widgets.Text.setText(Text.java:2305)
at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_custom_CTabFolder.createTabFolder(Test_org_eclipse_swt_custom_CTabFolder.java:140)

[Christopher-Hermann]

I did not took a detailed look in the original coding, but according to ChatGTP, we could just use a regex to normalize the String. See the coding:

/**
     * Normalize line breaks in a string to Windows line breaks (\r\n)
     *
     * @param input The input string
     * @return The string with normalized line breaks
     */
    public static String normalizeLineBreaks(String input) {
        // Replace \r\n, \r, or \n with \r\n
        return input.replaceAll("(\r\n|\r|\n)", "\r\n");
    }

This seems pretty easy and clean. Maybe you can give it a try.