Add "description cut off" warning at end too

This has to be slightly more clever than the warning at the beginning to try and avoid weird markdown rendering (so it looks reasonably clean) but it isn't *too* horrible.

Author: tianon

push.pl

@@ -96,7 +96,9 @@ sub prompt_for_edit {
 		my $fullUrl = "$githubBase/$proposedFile";
 		my $shortTags = "-\tSee [\"Supported tags and respective \`Dockerfile\` links\" at $fullUrl]($fullUrl#supported-tags-and-respective-dockerfile-links)\n\n";
 		my $tagsNote = "**Note:** the description for this image is longer than the Hub length limit of $lengthLimit, so the \"Supported tags\" list has been trimmed to compensate.  See [docker/hub-beta-feedback#238](https://github.com/docker/hub-beta-feedback/issues/238) for more information.\n\n" . $shortTags;
-		my $genericNote = "**Note:** the description for this image is longer than the Hub length limit of $lengthLimit, so has been trimmed.  The full description can be found at [$fullUrl]($fullUrl).  See [docker/hub-beta-feedback#238](https://github.com/docker/hub-beta-feedback/issues/238) for more information.\n\n";
+		my $genericNote = "**Note:** the description for this image is longer than the Hub length limit of $lengthLimit, so has been trimmed.  The full description can be found at [$fullUrl]($fullUrl).  See [docker/hub-beta-feedback#238](https://github.com/docker/hub-beta-feedback/issues/238) for more information.";
+		my $startingNote = $genericNote . "\n\n";
+		my $endingNote = "\n\n...\n\n" . $genericNote;
 
 		$tagsNote = $shortTags if $alwaysShortTags;
 
@@ -110,7 +112,19 @@ sub prompt_for_edit {
 
 		if (length($trimmedText) > $lengthLimit) {
 			# ... if that doesn't do the trick, then do our older naïve description trimming
-			$trimmedText = $genericNote . substr $proposedText, 0, ($lengthLimit - length($genericNote));
+			$trimmedText = $startingNote . substr $proposedText, 0, ($lengthLimit - length($startingNote . $endingNote));
+
+			# adding the "ending note" (https://github.com/docker/hub-feedback/issues/2220) is a bit more complicated as we have to deal with cutting off markdown ~cleanly so it renders correctly
+			# TODO deal with "```foo" appropriately (so we don't drop our note in the middle of a code block) - the Hub's current markdown rendering (2022-04-07) does not auto-close a dangling block like this, so this isn't urgent
+			if ($trimmedText =~ m/\n$/) {
+				# if we already end with a newline, we should be fine to just trim newlines and add our ending note
+				$trimmedText =~ s/\n+$//;
+			}
+			else {
+				# otherwise, we need to get a little bit more creative and trim back to the last fully blank line (which we can reasonably assume is safe thanks to our markdownfmt)
+				$trimmedText =~ s/\n\n(.\n?)*$//;
+			}
+			$trimmedText .= $endingNote;
 		}
 
 		$proposedText = $trimmedText;