replace dot with idseparator in generated ID (PR #2744)

3 files changed, 7 insertions, 7 deletions

diff --git a/lib/asciidoctor.rb b/lib/asciidoctor.rb
index bf8a992f..d089179f 100644
--- a/lib/asciidoctor.rb
+++ b/lib/asciidoctor.rb
@@ -655,7 +655,7 @@ module Asciidoctor
     # Matches invalid ID characters in a section title.
     #
     # NOTE uppercase chars not included since expression is only run on a lowercase string
-    InvalidSectionIdCharsRx = /<[^>]+>|&(?:[a-z][a-z]+\d{0,2}|#\d\d\d{0,4}|#x[\da-f][\da-f][\da-f]{0,3});|[^ #{CC_WORD}-]+?/
+    InvalidSectionIdCharsRx = /<[^>]+>|&(?:[a-z][a-z]+\d{0,2}|#\d\d\d{0,4}|#x[\da-f][\da-f][\da-f]{0,3});|[^ #{CC_WORD}\-.]+?/
 
     ## Lists
 
diff --git a/lib/asciidoctor/section.rb b/lib/asciidoctor/section.rb
index f1baab94..5ff15d9c 100644
--- a/lib/asciidoctor/section.rb
+++ b/lib/asciidoctor/section.rb
@@ -198,10 +198,10 @@ class Section < AbstractBlock
     pre = attrs['idprefix'] || '_'
     if (sep = attrs['idseparator'])
       if sep.length == 1 || (!(no_sep = sep.empty?) && (sep = attrs['idseparator'] = sep.chr))
-        sep_sub = sep == '-' ? ' -' : %( #{sep}-)
+        sep_sub = sep == '-' || sep == '.' ? ' .-' : %( #{sep}.-)
       end
     else
-      sep, sep_sub = '_', ' _-'
+      sep, sep_sub = '_', ' _.-'
     end
     gen_id = %(#{pre}#{title.downcase.gsub InvalidSectionIdCharsRx, ''})
     if no_sep
diff --git a/test/sections_test.rb b/test/sections_test.rb
index 5fde1109..34791b19 100644
--- a/test/sections_test.rb
+++ b/test/sections_test.rb
@@ -46,9 +46,9 @@ context 'Sections' do
       assert_equal '_state_of_the_art_design', sec.id
     end
 
-    test 'synthetic id drops dots' do
+    test 'synthetic id replaces dots with separator' do
       sec = block_from_string("== Section 1.1.1")
-      assert_equal '_section_111', sec.id
+      assert_equal '_section_1_1_1', sec.id
     end
 
     test 'synthetic id prefix can be customized' do
@@ -76,9 +76,9 @@ context 'Sections' do
       assert_equal '_state-of-the-art-design', sec.id
     end
 
-    test 'synthetic id separator can be dot' do
+    test 'synthetic id separator can be dot and dots are preserved' do
       sec = block_from_string(":idseparator: .\n\n== Version 5.0.1")
-      assert_equal '_version.501', sec.id
+      assert_equal '_version.5.0.1', sec.id
     end
 
     test 'synthetic id separator can only be one character' do