Don't crash on URLs with %20 inside

Without the fix configparser complains about bad interpolation:

    configparser.InterpolationSyntaxError: '%' must be followed by '%' or '(', found: '%20Latest%20Stable/2.0.10/zabbix-2.0.10.tar.gz'

nxdbom/__init__.py

@@ -78,14 +78,14 @@ def bom_software(installed_software_path): # -> {} name -> PkgInfo
         recipe = part['recipe']
 
         if recipe == 'slapos.recipe.cmmi':
-            addbom(part['url'], '')       # XXX detect kind?
+            addbom(geturl(part), '')    # XXX detect kind?
 
         elif recipe == 'slapos.recipe.build':
             # slapos.recipe.build is often used in creative ways to actually
             # run python code during the build. Let's detect this via lack of
             # `url`, but be careful and explicitly list name of such sections
             # not to miss a normal part.
-            url = part.get('url', None)
+            url = geturl(part, None)
             if url is None:
                 # [gcc] is generic section to either use system gcc, or install one via slapos
                 # the one installed via slapos will come in its own section
@@ -102,7 +102,7 @@ def bom_software(installed_software_path): # -> {} name -> PkgInfo
         elif recipe == 'slapos.recipe.build:download':
             # slapos.recipe.build:download is often used to download .conf files, but sometimes it is used to download e.g. binaries
             # skip the part, if we can detect that downloaded item is a configuration file
-            url = part['url']
+            url = geturl(part)
             if isconf(url):
                 continue
 
@@ -111,9 +111,9 @@ def bom_software(installed_software_path): # -> {} name -> PkgInfo
 
 
         elif recipe.startswith('slapos.recipe.template'):
-            url = part.get('url', None)
+            url = geturl(part, None)
             if url is not None:
-                if isconf(part['url']):
+                if isconf(url):
                     continue
                 # NOTE binary is not expected with slapos.recipe.template
                 raise ValueError('%s uses %s with url that does not look like a .conf file: %s' % (s, recipe, url))
@@ -151,6 +151,17 @@ def bom_software(installed_software_path): # -> {} name -> PkgInfo
     return bom
 
 
+# geturl returns value of part:url
+_missing = object()
+def geturl(part, default=_missing):
+    url = part.get('url', raw=True)     # raw because e.g. .../ZABBIX%20Latest%20Stable/...
+    if url is None:
+        if default is not _missing:
+            return default
+        raise KeyError('section %s has no url' % part)
+    return url
+
+
 def bom_node(XXX):
     1/0
     # TODO bom_node should:

nxdbom/nxdbom_test.py

@@ -104,6 +104,15 @@ lxml                         4.9.1      https://pypi.org/project/lxml/4.9.1/
 pycurl                       7.43.0     https://pypi.org/project/pycurl/7.43.0/
 """)
 
+# %20 in URL
+case1("""\
+[zabbix-agent]
+recipe = slapos.recipe.cmmi
+url = http://downloads.sourceforge.net/project/zabbix/ZABBIX%20Latest%20Stable/2.0.10/zabbix-2.0.10.tar.gz
+""", """\
+zabbix                       2.0.10     http://downloads.sourceforge.net/project/zabbix/ZABBIX%20Latest%20Stable/2.0.10/zabbix-2.0.10.tar.gz
+""")
+
 
 @pytest.mark.parametrize('build,bomok', testv)
 def test_bom_software(tmpdir, build, bomok):