From 969cec9322dcccf369fdb9334e98ec741d7d600e Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@users.mediawiki.org>
Date: Fri, 30 Sep 2011 22:50:48 +0000
Subject: [PATCH] * (bug 12130) Initial newlines are now preserved correctly
 during editing

HTML browsers strip the first newline from the literal contents of a <textarea>, but keep any additional newlines beyond that.

Prepending an extra newline in Html::textarea() when the contained text started with a newline makes our output basically look like this:

<textarea>             <-- (this added newline is ignored)
                       <-- (any original newline here is preserved)
blah blah</textarea>

This seems to consistently resolve the stripping of single initial newlines from every edit operation as seen on bug 12130; as noted on comments there <https://bugzilla.wikimedia.org/show_bug.cgi?id=12130#c17> this had deleterious effects on Wikisource, where transcription/proofreading tends to involve breaking up lots of little pages, which may have a significant newline at the start of a page boundary.

Text that didn't have initial newlines won't see any difference in the HTML output.

Followup to test cases in r98576, which confirm that supported browsers consistently have this behavior.
---
 includes/Html.php | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/includes/Html.php b/includes/Html.php
index 48cef6f6dd..e778c72ee7 100644
--- a/includes/Html.php
+++ b/includes/Html.php
@@ -685,7 +685,16 @@ class Html {
 			}
 		}
 
-		return self::element( 'textarea', $attribs, $value );
+		if (substr($value, 0, 1) == "\n") {
+			// Workaround for bug 12130: browsers eat the initial newline
+			// assuming that it's just for show, but they do keep the later
+			// newlines, which we may want to preserve during editing.
+			// Prepending a single newline
+			$spacedValue = "\n" . $value;
+		} else {
+			$spacedValue = $value;
+		}
+		return self::element( 'textarea', $attribs, $spacedValue );
 	}
 
 	/**
-- 
2.20.1