TokenNetworkRegistry proxy checks against secret_registry_address zero

[pirapira]

Fixes: #4882

Description

Please, describe what this PR does in detail:

• If it's a bug fix, detail the root cause of the bug and how this PR fixes it.

Before this PR, TokenNetworkRegistry sent a transaction even when secret_registry_address is zero, so the constructor of TokenNetwork would fail. After this PR, such transactions will not be sent. Moreover, when a sent transaction fails and secret_registry_address is zero, the proxy raises a RaidenUnrecoverableError because the proxy is probably talking to a wrong contract.

PR review check list

Quality check list that cannot be automatically verified.

• Safety
  • The changes respect the necessary conditions for safety (https://raiden-network-specification.readthedocs.io/en/latest/smart_contracts.html#protocol-values-constraints)
• Code quality
  • Error conditions are handled
  • Exceptions are propagated to the correct parent greenlet
  • Exceptions are correctly classified as recoverable or unrecoverable
• Compatibility
  • State changes are forward compatible
  • Transport messages are backwards and forward compatible
• Commits
  • Have good messages
  • Squashed unecessary commits
• If it's a bug fix:
  • Regression test for the bug
    • Properly covers the bug
    • If an integration test is used, it could not be written as a unit test
• Documentation
  • A new CLI flag was introduced, is there documentation that explains usage?
• Specs
  • If this is a protocol change, are the specs updated accordingly? If so, please link PR from the specs repo.
• Is it a user facing feature/bug fix?
  • Changelog entry has been added

[codecov]

Codecov Report

Merging #4883 into develop will increase coverage by 0.04%.
The diff coverage is 50%.

@@             Coverage Diff             @@
##           develop    #4883      +/-   ##
===========================================
+ Coverage    80.77%   80.81%   +0.04%     
===========================================
  Files          120      119       -1     
  Lines        14515    14461      -54     
  Branches      2238     2233       -5     
===========================================
- Hits         11724    11687      -37     
+ Misses        2133     2113      -20     
- Partials       658      661       +3

Impacted Files	Coverage Δ
raiden/network/proxies/token_network_registry.py	72.47% <50%> (-4.67%)	⬇️
raiden/network/rpc/middleware.py	57.89% <0%> (-42.11%)	⬇️
raiden/exceptions.py	96.61% <0%> (-3.39%)	⬇️
raiden/tasks.py	68.08% <0%> (-2.51%)	⬇️
raiden/raiden_service.py	90.6% <0%> (-1.95%)	⬇️
raiden/utils/echo_node.py	67.79% <0%> (-1.7%)	⬇️
raiden/log_config.py	87.61% <0%> (-1.58%)	⬇️
raiden/utils/runnable.py	88.23% <0%> (-1.13%)	⬇️
raiden/network/rpc/client.py	75.24% <0%> (-0.91%)	⬇️
... and 37 more

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[rakanalh]

According to the contracts:

https://github.com/raiden-network/raiden-contracts/blob/94f1428d2fad4719efffb26be3d7731d7bb3f3da/raiden_contracts/data/source/raiden/TokenNetworkRegistry.sol#L70-L105

There is no require/assert for the secret registry address when createERC20TokenNetwork is called.

The assert exists in the constructor of the contract which means that if that fails there would be no usable instance of the contracts.

I don't think this change in this PR is required.

[pirapira]

@rakanalh that function deploys TokenNetwork so you need to read the constructor of TokenNetwork as well. https://github.com/raiden-network/raiden-contracts/blob/94f1428d2fad4719efffb26be3d7731d7bb3f3da/raiden_contracts/data/source/raiden/TokenNetwork.sol#L229

When the require in TokenNetwork's constructor fails, TokenNetworkRegistry's createERC20TokenNetwork() function also fails.

[pirapira]

#4936 deals with the problem I was solving here.