Fix reporting of multiple detected eggs

It was failing with

                        if len(eggv) > 1:
    >                       raise ValueError('egg %s is present multiple times: %s' % (egg, eggv))
    E                       NameError: name 'egg' is not defined

I hit this for real when trying to build multiple SRs on the same Theia.

nxdbom/__init__.py

@@ -212,7 +212,8 @@ def bom_software(installed_software_path): # -> {} (name,kind) -> PkgInfo
                 if len(eggv) == 0:
                     raise ValueError('egg %s not found' % eggname)
                 if len(eggv) > 1:
-                    raise ValueError('egg %s is present multiple times: %s' % (egg, eggv))
+                    eggv.sort()
+                    raise ValueError('egg %s is present multiple times: %s' % (eggname, eggv))
                 addbom(eggv[0], 'egg')
 
         elif recipe == 'slapos.recipe.build:gitclone':

nxdbom/nxdbom_test.py

@@ -389,6 +389,19 @@ bbb                          3.4        https://pypi.org/project/bbb/3.4/
 ccc                          5.6.7      https://pypi.org/project/ccc/5.6.7/
 """)
 
+# multiple eggs are rejected
+# TODO try to improve zc.recipe.egg to emit information into .installed.cfg instead of us scanning the filesystem
+case1("""
+[ccc]
+recipe = zc.recipe.egg
+_d = /ROOT/develop-eggs
+_e = /ROOT/eggs
+eggs = setuptools
+-- /ROOT/eggs/setuptools-44.1.1-py3.7.egg --
+-- /ROOT/eggs/setuptools-44.1.1-py3.9.egg --
+""",
+ValueError("egg setuptools is present multiple times: ['setuptools-44.1.1-py3.7.egg', 'setuptools-44.1.1-py3.9.egg']"))
+
 # libreoffice
 case1("""\
 [libreoffice-bin]
@@ -422,8 +435,13 @@ def test_bom_software(tmpdir, build, bomok):
         with open(f, 'w') as _:
             _.write(data)
 
-    bom = nxdbom.bom_software(tmpdir)
-    assert nxdbom.fmt_bom(bom) == bomok
+    if isinstance(bomok, Exception):
+        with pytest.raises(type(bomok)) as e:
+            nxdbom.bom_software(tmpdir)
+        assert str(e.value) == str(bomok)
+    else:
+        bom = nxdbom.bom_software(tmpdir)
+        assert nxdbom.fmt_bom(bom) == bomok
 
 
 # loading non-existing .installed.cfg -> error