--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2011-12-25  Jim Meyering  <meyering@redhat.com>
+
+	gitlog-to-changelog: do not clump multi-paragraph entries
+	Identical header lines (date,name,email+coauthors) are suppressed,
+	thus putting all entries with those same characteristics under
+	a single header.  However, when a log entry consists of two or
+	more paragraphs, it may not be clear where it starts and ends.
+	This change makes it so that such an entry is always separated
+	from others by a header line, even when that header would
+	otherwise be suppressed.
+	* build-aux/gitlog-to-changelog: Implement the above.
+	Inspired by a related request from Stefano Lattarini in
+	http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/29456
+
 2011-12-25  Paul Eggert  <eggert@cs.ucla.edu>
 
 	announce-gen: fix `cmd' typo in diagnostic

--- a/build-aux/gitlog-to-changelog
+++ b/build-aux/gitlog-to-changelog
@@ -3,7 +3,7 @@
     if 0;
 # Convert git log output to ChangeLog format.
 
-my $VERSION = '2011-11-02 07:53'; # UTC
+my $VERSION = '2011-12-24 18:51'; # UTC
 # The definition above must lie within the first 8 lines in order
 # for the Emacs time-stamp write hook (at end) to update it.
 # If you change this file with Emacs, please let the write hook
@@ -199,6 +199,7 @@
     or die ("$ME: failed to run `". quoted_cmd (@cmd) ."': $!\n"
             . "(Is your Git too old?  Version 1.5.1 or later is required.)\n");
 
+  my $prev_multi_paragraph;
   my $prev_date_line = '';
   my @prev_coauthors = ();
   while (1)
@@ -248,12 +249,25 @@
       $author_line =~ /^(\d+)  (.*>)$/
         or die "$ME:$.: Invalid line "
           . "(expected date/author/email):\n$author_line\n";
+      my $date_line = sprintf "%s  $2\n", strftime ("%F", localtime ($1));
 
-      my $date_line = sprintf "%s  $2\n", strftime ("%F", localtime ($1));
+      my @coauthors = grep /^Co-authored-by:.*$/, @line;
+      # Omit "Co-authored-by..." and "Signed-off-by..." lines.
+      @line = grep !/^Signed-off-by: .*>$/, @line;
+      @line = grep !/^Co-authored-by: /, @line;
+
+      # Remove leading and trailing blank lines.
+      if (@line)
+        {
+          while ($line[0] =~ /^\s*$/) { shift @line; }
+          while ($line[$#line] =~ /^\s*$/) { pop @line; }
+        }
+
+      # Record whether there are two or more paragraphs.
+      my $multi_paragraph = grep /^\s*$/, @line;
 
       # Format 'Co-authored-by: A U Thor <email@example.com>' lines in
       # standard multi-author ChangeLog format.
-      my @coauthors = grep /^Co-authored-by:.*$/, @line;
       for (@coauthors)
         {
           s/^Co-authored-by:\s*/\t    /;
@@ -264,9 +278,13 @@
               . substr ($_, 5) . "\n";
         }
 
-      # If this header would be the same as the previous date/name/email/
-      # coauthors header, then arrange not to print it.
-      if ($date_line ne $prev_date_line or "@coauthors" ne "@prev_coauthors")
+      # If this header would be different from the previous date/name/email/
+      # coauthors header, or if this or the previous entry consists of two
+      # or more paragraphs, then print the header.
+      if ($date_line ne $prev_date_line
+          or "@coauthors" ne "@prev_coauthors"
+          or $multi_paragraph
+          or $prev_multi_paragraph)
         {
           $prev_date_line eq ''
             or print "\n";
@@ -276,17 +294,7 @@
         }
       $prev_date_line = $date_line;
       @prev_coauthors = @coauthors;
-
-      # Omit "Co-authored-by..." and "Signed-off-by..." lines.
-      @line = grep !/^Signed-off-by: .*>$/, @line;
-      @line = grep !/^Co-authored-by: /, @line;
-
-      # Remove leading and trailing blank lines.
-      if (@line)
-        {
-          while ($line[0] =~ /^\s*$/) { shift @line; }
-          while ($line[$#line] =~ /^\s*$/) { pop @line; }
-        }
+      $prev_multi_paragraph = $multi_paragraph;
 
       # If there were any lines
       if (@line == 0)