Merge branch 'ab/gitweb-abbrev-links'

In addition to purely abbreviated commit object names, "gitweb"
learned to turn "git describe" output (e.g. v2.9.3-599-g2376d31787)
into clickable links in its output.

* ab/gitweb-abbrev-links:
  gitweb: link to "git describe"'d commits in log messages
  gitweb: link to 7-char+ SHA-1s, not only 8-char+
  gitweb: fix a typo in a comment

gitweb/gitweb.perl

@@ -1616,7 +1616,7 @@ sub esc_path {
 	return $str;
 }
 
-# Sanitize for use in XHTML + application/xml+xhtm (valid XML 1.0)
+# Sanitize for use in XHTML + application/xml+xhtml (valid XML 1.0)
 sub sanitize {
 	my $str = shift;
 
@@ -2036,10 +2036,24 @@ sub format_log_line_html {
 	my $line = shift;
 
 	$line = esc_html($line, -nbsp=>1);
-	$line =~ s{\b([0-9a-fA-F]{8,40})\b}{
+	$line =~ s{
+        \b
+        (
+            # The output of "git describe", e.g. v2.10.0-297-gf6727b0
+            # or hadoop-20160921-113441-20-g094fb7d
+            (?<!-) # see strbuf_check_tag_ref(). Tags can't start with -
+            [A-Za-z0-9.-]+
+            (?!\.) # refs can't end with ".", see check_refname_format()
+            -g[0-9a-fA-F]{7,40}
+            |
+            # Just a normal looking Git SHA1
+            [0-9a-fA-F]{7,40}
+        )
+        \b
+    }{
 		$cgi->a({-href => href(action=>"object", hash=>$1),
 					-class => "text"}, $1);
-	}eg;
+	}egx;
 
 	return $line;
 }