kernel-doc: detect/prevent duplicate doc section names

I saw this problem recently.  With this kernel-doc:

 * Note: some important info
 *
 * Note: other important info

kernel-doc uses the "section name" (preceding the ':', like "Note") as a hash
key for storing the descriptive text ("blah important info").  It is (was)
possible to have duplicate (colliding) section names, without any kind of
warning or error.

kernel-doc happily used the latter descriptive text for all instances of
printing the <section-name> descriptive text and the former important info
was lost.

One way to "fix" this is to modify the kernel-doc comments, e.g.:

 * Note1: foo bar
 *
 * Note.2: blah zay

For now, kernel-doc will signal an error when it sees colliding section names
like this.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 7 deletions

diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 263d04ab2d94..99364a5e77f2 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -5,7 +5,7 @@ use strict;
 ## Copyright (c) 1998 Michael Zucchi, All Rights Reserved        ##
 ## Copyright (C) 2000, 1  Tim Waugh <twaugh@redhat.com>          ##
 ## Copyright (C) 2001  Simon Huggins                             ##
-## Copyright (C) 2005-2007  Randy Dunlap                         ##
+## Copyright (C) 2005-2008  Randy Dunlap                         ##
 ##                                                               ##
 ## #define enhancements by Armin Kuster <akuster@mvista.com>     ##
 ## Copyright (c) 2000 MontaVista Software, Inc.                  ##
@@ -366,6 +366,7 @@ foreach my $pattern (keys %highlights) {
 # dumps section contents to arrays/hashes intended for that purpose.
 #
 sub dump_section {
+    my $file = shift;
     my $name = shift;
     my $contents = join "\n", @_;
 
@@ -379,6 +380,10 @@ sub dump_section {
         $parameterdescs{$name} = $contents;
     } else {
 #       print STDERR "other section '$name' = '$contents'\n";
+        if (defined($sections{$name}) && ($sections{$name} ne "")) {
+                print STDERR "Error(${file}:$.): duplicate section name '$name'\n";
+                ++$errors;
+        }
         $sections{$name} = $contents;
         push @sectionlist, $name;
     }
@@ -388,6 +393,7 @@ sub dump_section {
 # dump DOC: section after checking that it should go out
 #
 sub dump_doc_section {
+    my $file = shift;
     my $name = shift;
     my $contents = join "\n", @_;
 
@@ -399,7 +405,7 @@ sub dump_doc_section {
         ( $function_only == 1 && defined($function_table{$name})) ||
         ( $function_only == 2 && !defined($function_table{$name})))
     {
-        dump_section $name, $contents;
+        dump_section($file, $name, $contents);
         output_blockhead({'sectionlist' => \@sectionlist,
                           'sections' => \%sections,
                           'module' => $modulename,
@@ -1923,7 +1929,7 @@ sub process_file($) {
                         print STDERR "Warning(${file}:$.): contents before sections\n";
                         ++$warnings;
                     }
-                    dump_section($section, xml_escape($contents));
+                    dump_section($file, $section, xml_escape($contents));
                     $section = $section_default;
                 }
 
@@ -1940,7 +1946,7 @@ sub process_file($) {
             } elsif (/$doc_end/) {
 
                 if ($contents ne "") {
-                    dump_section($section, xml_escape($contents));
+                    dump_section($file, $section, xml_escape($contents));
                     $section = $section_default;
                     $contents = "";
                 }
@@ -1954,7 +1960,7 @@ sub process_file($) {
                 # @parameter line to signify start of description
                 if ($1 eq "" &&
                         ($section =~ m/^@/ || $section eq $section_context)) {
-                    dump_section($section, xml_escape($contents));
+                    dump_section($file, $section, xml_escape($contents));
                     $section = $section_default;
                     $contents = "";
                 } else {
@@ -1974,7 +1980,7 @@ sub process_file($) {
         } elsif ($state == 4) {
                 # Documentation block
                 if (/$doc_block/) {
-                        dump_doc_section($section, xml_escape($contents));
+                        dump_doc_section($file, $section, xml_escape($contents));
                         $contents = "";
                         $function = "";
                         %constants = ();
@@ -1992,7 +1998,7 @@ sub process_file($) {
                 }
                 elsif (/$doc_end/)
                 {
-                        dump_doc_section($section, xml_escape($contents));
+                        dump_doc_section($file, $section, xml_escape($contents));
                         $contents = "";
                         $function = "";
                         %constants = ();