Treat pre-existing dependency issues as warnings (exit code 0)

When we notice a pre-existing dependency issue, it seems strange
to exit non-zero, since the update being tested didn't break
anything new. Let's just treat it more like a warning. Let's exit
0 in this case as there's no 'warning' exit code; the pipelines
can use the JSON output to report an INFO or WARN result.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

src/rmdepcheck/shared.py

@@ -316,14 +316,6 @@ def parse_display_exit(
             else:
                 format_rc_errors(newrc, form="strip")
         exitcode += 2
-    if preexisting:
-        if dojson:
-            jsonout["installability_preexisting"] = [list(err) for err in preexisting]
-        else:
-            print("")
-            print("Pre-existing dependency problems in the tested packages themselves:")
-            format_rc_errors(preexisting)
-        exitcode += 4
     if fixederrors:
         if dojson:
             jsonout["fixederrors"] = [list(err) for err in fixederrors]
@@ -331,6 +323,13 @@ def parse_display_exit(
             print("")
             print(f"Dependencies of other packages that would be FIXED by {iut}:")
             format_rc_errors(fixederrors)
+    if preexisting:
+        if dojson:
+            jsonout["installability_preexisting"] = [list(err) for err in preexisting]
+        else:
+            print("")
+            print("Warning: pre-existing dependency problems in the tested packages themselves:")
+            format_rc_errors(preexisting)
     if dojson:
         json.dump(jsonout, sys.stdout, indent=4)
         sys.stdout.write("\n")

tests/test_rmdepcheck.py

@@ -421,7 +421,7 @@ class TestE2E:
             sys.argv.insert(1, "--json")
         with pytest.raises(SystemExit) as excinfo:
             repos.main()
-        assert excinfo.value.code == 4
+        assert excinfo.value.code == 0
         captured = capsys.readouterr()
         if output == "human":
             fname = "test_e2e_unfixed.txt"

tests/testdata/test_e2e_unfixed.txt

@@ -1,4 +1,4 @@
 
-Pre-existing dependency problems in the tested packages themselves:
+Warning: pre-existing dependency problems in the tested packages themselves:
 package: ddd-3.0-1.x86_64 from file://{REPOS}/unfixed
   ccc = 3.0