Allow more than one version of the same software

In SlapOS we do in fact support/allow different versions for different
dependencies, so there isn't a reason why this should be disallowed.

nxdbom/__init__.py

@@ -83,7 +83,7 @@ def bom_software(installed_software_path): # -> {} (name,kind) -> PkgInfo
 
 
         info = PkgInfo(name, ver, kind, url)
-        bkey = (name, kind)
+        bkey = (name, kind, ver)
         if bkey in bom:
             assert bom[bkey] == info,  (bom[bkey], info)
         else:

nxdbom/nxdbom_test.py

@@ -455,6 +455,20 @@ url = http://snowball.tartarus.org/dist/libstemmer_c.tgz
 libstemmer_c                            http://snowball.tartarus.org/dist/libstemmer_c.tgz
 """)
 
+# two different versions of the same software are ok
+case1("""\
+[scons-0]
+recipe = slapos.recipe.build:download-unpacked
+url = https://prdownloads.sourceforge.net/scons/scons-local-2.3.0.tar.gz
+
+[scons-1]
+recipe = slapos.recipe.build:download-unpacked
+url = https://prdownloads.sourceforge.net/scons/scons-local-2.3.1.tar.gz
+""", """\
+scons-local                  2.3.0      https://prdownloads.sourceforge.net/scons/scons-local-2.3.0.tar.gz
+scons-local                  2.3.1      https://prdownloads.sourceforge.net/scons/scons-local-2.3.1.tar.gz
+""")
+
 
 @pytest.mark.parametrize('build,bomok', testv)
 def test_bom_software(tmpdir, build, bomok):