[gtk-doc] mkdb: only output object_index.sgml if not empty

[Stefan Sauer <stefkost src gnome org>]

commit 51e19ce72c11241c8dd81812631e5f20b3de645e
Author: Stefan Sauer <ensonic users sf net>
Date:   Sun Sep 8 21:42:57 2019 +0200

    mkdb: only output object_index.sgml if not empty
    
    Only output the index if the library provices gobjects. We already do this
    for the tree_index.sgml.

 NEWS            |  4 ++++
 gtkdoc/mkdb.py  | 18 +++++++++---------
 tests/sanity.sh | 24 +++++++++++++-----------
 3 files changed, 26 insertions(+), 20 deletions(-)
---
diff --git a/NEWS b/NEWS
index 9778c7e..41b80f9 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,10 @@ GTK-Doc 1.32.1  (Aug 15 2019)
 
 Dev version
 
+This version does not generate object_index.sgml if the library contains no
+gobjects.
+
+
 GTK-Doc 1.32  (Aug 15 2019)
 ===============
 
diff --git a/gtkdoc/mkdb.py b/gtkdoc/mkdb.py
index 9d910cb..9404452 100644
--- a/gtkdoc/mkdb.py
+++ b/gtkdoc/mkdb.py
@@ -341,7 +341,7 @@ def Run(options):
         logging.info('namespace prefix ="%s"', NAME_SPACE)
 
         OutputObjectTree(obj_tree)
-        OutputObjectList()
+        OutputObjectList(Objects)
 
         OutputIndex("api-index-full", IndexEntriesFull)
         OutputIndex("api-index-deprecated", IndexEntriesDeprecated)
@@ -354,10 +354,15 @@ def Run(options):
     logging.info("All files created: %d", changed)
 
 
-def OutputObjectList():
+def OutputObjectList(obj_list):
     """This outputs the alphabetical list of objects, in a columned table."""
     # FIXME: Currently this also outputs ancestor objects which may not actually
     # be in this module.
+
+    # TODO(ensonic): consider not writing this unconditionally
+    if not obj_list:
+        return
+
     cols = 3
 
     # FIXME: use .xml
@@ -386,13 +391,8 @@ def OutputObjectList():
             OUTPUT.write("</row>\n")
         count += 1
 
-    if count == 0:
-        # emit an empty row, since empty tables are invalid
-        OUTPUT.write("<row><entry> </entry></row>\n")
-
-    else:
-        if count % cols > 0:
-            OUTPUT.write("</row>\n")
+    if count % cols > 0:
+        OUTPUT.write("</row>\n")
 
     OUTPUT.write('''</tbody></tgroup></informaltable>\n''')
     OUTPUT.close()
diff --git a/tests/sanity.sh b/tests/sanity.sh
index 8c1f2a8..68db064 100755
--- a/tests/sanity.sh
+++ b/tests/sanity.sh
@@ -56,17 +56,19 @@ if test $nok -gt 0 ; then failed=`expr $failed + 1`; fi
 tested=`expr $tested + 1`
 
 
-# check validity of generated sgml files
-nok=0
-for file in $dir/$suite/docs/xml/*.sgml; do
-  xmllint --noout --noent $file
-  if test $? != 0 ; then
-    echo 1>&2 "sgml validity check failed for $file"
-    nok=`expr $nok + 1`;
-  fi
-done
-if test $nok -gt 0 ; then failed=`expr $failed + 1`; fi
-tested=`expr $tested + 1`
+# check validity of generated sgml files (if any)
+if ls $dir/$suite/docs/xml/*.sgml 1> /dev/null 2>&1; then
+  nok=0
+  for file in $dir/$suite/docs/xml/*.sgml; do
+    xmllint --noout --noent $file
+    if test $? != 0 ; then
+      echo 1>&2 "sgml validity check failed for $file"
+      nok=`expr $nok + 1`;
+    fi
+  done
+  if test $nok -gt 0 ; then failed=`expr $failed + 1`; fi
+  tested=`expr $tested + 1`
+fi
 
 # check validity of devhelp2 files
 nok=0