Description of problem:

In dependency resolution, Subscription uniqueness is currently based on the subscribed package name. If two Subscriptions in a namespace subscribe to the same package, they are treated as a single Subscription internally, resulting in some surprising behaviors.

Version-Release number of selected component (if applicable): 4.6

How reproducible: Always

Steps to Reproduce:
1. Subscribe to an operator:

$ cat << EOF | kubectl create -f-
apiVersion: v1
kind: Namespace
metadata:
  name: test-namespace
---
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: test-operatorgroup
  namespace: test-namespace
spec:
  targetNamespaces:
  - test-namespace
---
apiVersion: operators.coreos.com/v1alpha1
kind: CatalogSource
metadata:
  name: test-catalog
  namespace: test-namespace
spec:
  displayName: Community Operators
  image: quay.io/operatorhubio/catalog:latest
  sourceType: grpc
---
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: test-subscription-stable
  namespace: test-namespace
spec:
  name: redis-operator
  source: test-catalog
  sourceNamespace: test-namespace
  channel: stable
  startingCSV: redis-operator.v0.4.0
EOF

namespace/test-namespace created
operatorgroup.operators.coreos.com/test-operatorgroup created
catalogsource.operators.coreos.com/test-catalog created
subscription.operators.coreos.com/test-subscription-stable created

2. Wait for the operator to be installed:

$ kubectl -n test-namespace get csv -w

NAME                    DISPLAY          VERSION   REPLACES                PHASE
redis-operator.v0.4.0   Redis Operator   0.4.0     redis-operator.v0.3.0   
redis-operator.v0.4.0   Redis Operator   0.4.0     redis-operator.v0.3.0   Pending
redis-operator.v0.4.0   Redis Operator   0.4.0     redis-operator.v0.3.0   InstallReady
redis-operator.v0.4.0   Redis Operator   0.4.0     redis-operator.v0.3.0   Installing
redis-operator.v0.4.0   Redis Operator   0.4.0     redis-operator.v0.3.0   Installing
redis-operator.v0.4.0   Redis Operator   0.4.0     redis-operator.v0.3.0   Succeeded

3. Create a conflicting subscription to the same package:

$ cat << EOF | kubectl create -f-
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: test-subscription-alpha
  namespace: test-namespace
spec:
  name: redis-operator
  source: test-catalog
  sourceNamespace: test-namespace
  channel: alpha
  startingCSV: redis-operator.v0.0.1
EOF

subscription.operators.coreos.com/test-subscription-alpha created

Expected results:

Resolution should warn about a conflict between the installed v0.4.0 CSV and the requested v0.0.1 operator from the same package, something like this:

$ kubectl logs -n openshift-operator-lifecycle-manager deploy/catalog-operator | grep ResolutionFailed | tail -1

I0223 18:08:32.095488       1 event.go:282] Event(v1.ObjectReference{Kind:"Namespace", Namespace:"", Name:"test-namespace", UID:"59f61254-01b3-4309-9ecc-3ff29f1d979f", APIVersion:"v1", ResourceVersion:"851", FieldPath:""}): type: 'Warning' reason: 'ResolutionFailed' constraints not satisfiable: subscription test-subscription-stable requires @existing/test-namespace//redis-operator.v0.4.0, subscription test-subscription-stable exists, subscription test-subscription-alpha requires test-catalog/test-namespace/alpha/redis-operator.v0.0.1, subscription test-subscription-alpha exists, @existing/test-namespace//redis-operator.v0.4.0 and test-catalog/test-namespace/alpha/redis-operator.v0.0.1 originate from package redis-operator

Actual results:

The conflict between the two subscriptions is not indicated in the catalog-operator log. There may be some warnings that occur before the CatalogSource becomes available. Those would not indicate that there are two subscriptions to the redis-operator package, and may look something like this:

$ kubectl logs -n openshift-operator-lifecycle-manager deploy/catalog-operator | grep ResolutionFailed | tail -1

I0223 18:03:02.611310       1 event.go:282] Event(v1.ObjectReference{Kind:"Namespace", Namespace:"", Name:"test-namespace", UID:"27194bfe-65ee-4d24-86b0-6384fb6fb1a6", APIVersion:"v1", ResourceVersion:"855", FieldPath:""}): type: 'Warning' reason: 'ResolutionFailed' constraints not satisfiable: no operators found matching the subscription criteria for redis-operator, a subscription to package redis-operator exists in the namespace