From 51fc7782472cdfb1905aa48f405c0f192ba6c373 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ale=C5=A1=20Mat=C4=9Bj?= <amatej@redhat.com>
Date: Wed, 27 Sep 2023 08:27:58 +0200
Subject: [PATCH] xml parsing: fix a crash on valid xml with but no comps

On input like:
```
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE variants PUBLIC "-//Red Hat, Inc.//DTD Variants info//EN" "variants.dtd">
<variants>
</variants>
```
the document is parsed but there is no `comps_doc` so we cannot work
with it.

Also adds a unit test.
---
 libcomps/src/comps_parse.c          | 6 +++---
 libcomps/src/python/tests/__test.py | 9 +++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/libcomps/src/comps_parse.c b/libcomps/src/comps_parse.c
index 18133a2..7b4bf3c 100644
--- a/libcomps/src/comps_parse.c
+++ b/libcomps/src/comps_parse.c
@@ -176,21 +176,21 @@ int comps_parse_validate_dtd(char *filename, char *dtd_file) {
 }
 
 void __comps_after_parse(COMPS_Parsed *parsed) {
-    if (parsed->doctype_name) {
+    if (parsed->doctype_name && parsed->comps_doc) {
         COMPS_OBJECT_DESTROY(parsed->comps_doc->doctype_name);
         parsed->comps_doc->doctype_name = (COMPS_Str*)
                                   COMPS_OBJECT_INCREF(parsed->doctype_name);
     } else {
         //parsed->comps_doc->doctype_name = comps_str(comps_default_doctype_name);
     }
-    if (parsed->doctype_sysid) {
+    if (parsed->doctype_sysid && parsed->comps_doc) {
         COMPS_OBJECT_DESTROY(parsed->comps_doc->doctype_sysid);
         parsed->comps_doc->doctype_sysid = (COMPS_Str*)
                                   COMPS_OBJECT_INCREF(parsed->doctype_sysid);
     } else {
         //parsed->comps_doc->doctype_sysid = comps_str(comps_default_doctype_sysid);
     }
-    if (parsed->doctype_pubid) {
+    if (parsed->doctype_pubid && parsed->comps_doc) {
         COMPS_OBJECT_DESTROY(parsed->comps_doc->doctype_pubid);
         parsed->comps_doc->doctype_pubid = (COMPS_Str*)
                                   COMPS_OBJECT_INCREF(parsed->doctype_pubid);
diff --git a/libcomps/src/python/tests/__test.py b/libcomps/src/python/tests/__test.py
index ba4b349..18200c5 100644
--- a/libcomps/src/python/tests/__test.py
+++ b/libcomps/src/python/tests/__test.py
@@ -743,6 +743,15 @@ def test_xml(self):
         # return code 1 is non fatal error
         self.assertTrue(ret == 1, comps5.get_last_errors())
 
+        VALID_XML_HEADER_NO_COMPS = """<?xml version="1.0" encoding="UTF-8"?>
+        <!DOCTYPE variants PUBLIC "-//Red Hat, Inc.//DTD Variants info//EN" "variants.dtd">
+        <variants>
+        </variants>"""
+        comps6 = libcomps.Comps()
+        ret = comps6.fromxml_str(str(VALID_XML_HEADER_NO_COMPS))
+        # return code 1 is non fatal error
+        self.assertTrue(ret == 1, comps6.get_last_errors())
+
 
     #@unittest.skip("")
     def test_fedora(self):