Lua: improve handling of empty caption, body by `from_simple_table`

Create truly empty table caption and body when these are empty in the
simple table.

Fixes: #7776

2 files changed, 29 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Lua/Module/Utils.hs b/src/Text/Pandoc/Lua/Module/Utils.hs
index eabb2b532..02307cf7a 100644
--- a/src/Text/Pandoc/Lua/Module/Utils.hs
+++ b/src/Text/Pandoc/Lua/Module/Utils.hs
@@ -197,10 +197,10 @@ from_simple_table :: SimpleTable -> LuaE PandocError NumResults
 from_simple_table (SimpleTable capt aligns widths head' body) = do
   Lua.push $ Table
     nullAttr
-    (Caption Nothing [Plain capt])
+    (Caption Nothing [Plain capt | not (null capt)])
     (zipWith (\a w -> (a, toColWidth w)) aligns widths)
     (TableHead nullAttr [blockListToRow head' | not (null head') ])
-    [TableBody nullAttr 0 [] $ map blockListToRow body]
+    [TableBody nullAttr 0 [] $ map blockListToRow body | not (null body)]
     (TableFoot nullAttr [])
   return (NumResults 1)
   where
diff --git a/test/lua/module/pandoc-utils.lua b/test/lua/module/pandoc-utils.lua
index 0475e96ec..4cf2c84a7 100644
--- a/test/lua/module/pandoc-utils.lua
+++ b/test/lua/module/pandoc-utils.lua
@@ -302,5 +302,32 @@ return {
       -- reversible
       assert.are_same(simple_table, utils.to_simple_table(tbl))
     end),
+    test('empty caption', function ()
+      local simple_table = pandoc.SimpleTable(
+        {},
+        {pandoc.AlignDefault},
+        {0},
+        {{pandoc.Plain 'a'}},
+        {{{pandoc.Plain 'b'}}}
+      )
+      local tbl = utils.from_simple_table(simple_table)
+      assert.are_equal(
+        pandoc.Blocks{},
+        tbl.caption.long
+      )
+      assert.is_nil(tbl.caption.short)
+    end),
+    test('empty body', function ()
+      local simple_table = pandoc.SimpleTable(
+        pandoc.Inlines('a nice caption'),
+        {pandoc.AlignDefault},
+        {0},
+        {{pandoc.Plain 'a'}},
+        {}
+      )
+      local tbl = utils.from_simple_table(simple_table)
+      tbl.bodies:map(print)
+      assert.are_same(pandoc.List(), tbl.bodies)
+    end),
   }
 }