Fix: Defaults for onChain Parameters to Prevent Halt on Not Set Values Expected to Exist

[gzukel]

Describe the Bug
A recent system upgrade encountered an issue where an emissions parameter was not set, leading to a halt of the binary. To prevent such occurrences, it is proposed that all parameters expected by the Chain should have default values unless explicitly set or overridden. This approach would ensure that the addition of new parameters does not cause a system panic due to missing state information, by instantiating a default value when the parameter is not present in the state. However, if the parameter is explicitly set, the system should utilize the specified value.

To Reproduce

• Conduct a system upgrade without setting a new emissions parameter that is expected to have a value. Thus, when the binary starts and tries to load the parameter from state it errors on json parsing because it expected a json key to exist where it didn't.
• Observe the resulting binary halt due to the absence of this parameter.

Expected Behavior
The system should automatically assign a default value to any new parameter that is not explicitly set in the state during an upgrade. This action would prevent the system from halting and ensure smooth operation, even when new parameters are introduced.

Screenshots/Logs

panic: UnmarshalJSON cannot decode empty bytes

goroutine 1 [running]:
github.com/cosmos/cosmos-sdk/x/params/types.Subspace.Get({{0x3dbd230, 0xc0014561d0}, 0xc000b81390, {0x3d8a470, 0xc001e42340}, {0x3d8a4c0, 0xc001e423f0}, {0xc00055c5a0, 0x9, 0x24}, ...}, ...)
	/root/go/pkg/mod/github.com/cosmos/[email protected]/x/params/types/subspace.go:110 +0x2c7
github.com/cosmos/cosmos-sdk/x/params/types.Subspace.GetParamSet({{0x3dbd230, 0xc0014561d0}, 0xc000b81390, {0x3d8a470, 0xc001e42340}, {0x3d8a4c0, 0xc001e423f0}, {0xc00055c5a0, 0x9, 0x24}, ...}, ...)
	/root/go/pkg/mod/github.com/cosmos/[email protected]/x/params/types/subspace.go:239 +0x106
github.com/zeta-chain/zetacore/x/emissions/keeper.Keeper.GetParams(...)
	/go/src/github.com/zeta-chain/node/x/emissions/keeper/params.go:10
github.com/zeta-chain/zetacore/x/emissions.BeginBlocker({{0x3da86b8, 0xc0000560b0}, {0x3dbdcb0, 0xc00364df00}, {{0xb, 0x0}, {0xc010d25e20, 0x10}, 0x1fa86a, {0x2b019d02, ...}, ...}, ...}, ...)
	/go/src/github.com/zeta-chain/node/x/emissions/abci.go:22 +0x2e8
github.com/zeta-chain/zetacore/x/emissions.AppModule.BeginBlock(...)
	/go/src/github.com/zeta-chain/node/x/emissions/module.go:172
github.com/cosmos/cosmos-sdk/types/module.(*Manager).BeginBlock(_, {{0x3da86b8, 0xc0000560b0}, {0x3dbdcb0, 0xc00364df00}, {{0xb, 0x0}, {0xc010d25e20, 0x10}, 0x1fa86a, ...}, ...}, ...)
	/root/go/pkg/mod/github.com/cosmos/[email protected]/types/module/module.go:484 +0x1bb
github.com/zeta-chain/zetacore/app.(*App).BeginBlocker(...)
	/go/src/github.com/zeta-chain/node/app/app.go:618
github.com/cosmos/cosmos-sdk/baseapp.(*BaseApp).BeginBlock(_, {{0xc001e32fa0, 0x20, 0x20}, {{0xb, 0x0}, {0xc010d25e20, 0x10}, 0x1fa86a, {0x2b019d02, ...}, ...}, ...})
	/root/go/pkg/mod/github.com/cosmos/[email protected]/baseapp/abci.go:183 +0x843
github.com/tendermint/tendermint/abci/client.(*localClient).BeginBlockSync(_, {{0xc001e32fa0, 0x20, 0x20}, {{0xb, 0x0}, {0xc010d25e20, 0x10}, 0x1fa86a, {0x2b019d02, ...}, ...}, ...})
	/root/go/pkg/mod/github.com/cometbft/[email protected]/abci/client/local_client.go:280 +0x118
github.com/tendermint/tendermint/proxy.(*appConnConsensus).BeginBlockSync(_, {{0xc001e32fa0, 0x20, 0x20}, {{0xb, 0x0}, {0xc010d25e20, 0x10}, 0x1fa86a, {0x2b019d02, ...}, ...}, ...})
	/root/go/pkg/mod/github.com/cometbft/[email protected]/proxy/app_conn.go:81 +0x55
github.com/tendermint/tendermint/state.execBlockOnProxyApp({0x3daa130?, 0xc0058c0180}, {0x3db44c0, 0xc0018d4460}, 0xc001792000, {0x3dbf248, 0xc082724018}, 0x1fa869?)
	/root/go/pkg/mod/github.com/cometbft/[email protected]/state/execution.go:307 +0x51d
github.com/tendermint/tendermint/state.(*BlockExecutor).ApplyBlock(_, {{{0xb, 0x0}, {0xc0018d06b8, 0x7}}, {0xc0018d06f0, 0x10}, 0x1, 0x1fa869, {{0xc0446a20a0, ...}, ...}, ...}, ...)
	/root/go/pkg/mod/github.com/cometbft/[email protected]/state/execution.go:140 +0x171
github.com/tendermint/tendermint/consensus.(*Handshaker).replayBlock(_, {{{0xb, 0x0}, {0xc0018d06b8, 0x7}}, {0xc0018d06f0, 0x10}, 0x1, 0x1fa869, {{0xc0446a20a0, ...}, ...}, ...}, ...)
	/root/go/pkg/mod/github.com/cometbft/[email protected]/consensus/replay.go:503 +0x23c
github.com/tendermint/tendermint/consensus.(*Handshaker).ReplayBlocks(_, {{{0xb, 0x0}, {0xc0018d06b8, 0x7}}, {0xc0018d06f0, 0x10}, 0x1, 0x1fa869, {{0xc0446a20a0, ...}, ...}, ...}, ...)
	/root/go/pkg/mod/github.com/cometbft/[email protected]/consensus/replay.go:416 +0x7ae
github.com/tendermint/tendermint/consensus.(*Handshaker).Handshake(0xc01139cf90, {0x3dc1610, 0xc001b72ea0})
	/root/go/pkg/mod/github.com/cometbft/[email protected]/consensus/replay.go:268 +0x3d4
github.com/tendermint/tendermint/node.doHandshake({_, _}, {{{0xb, 0x0}, {0xc0018d06b8, 0x7}}, {0xc0018d06f0, 0x10}, 0x1, 0x1fa869, ...}, ...)
	/root/go/pkg/mod/github.com/cometbft/[email protected]/node/node.go:329 +0x1b8
github.com/tendermint/tendermint/node.NewNode(0xc000da32c0, {0x3da0600, 0xc001b63860}, 0xc001c68230, {0x3d80880, 0xc04296a480}, 0x1?, 0x5736700?, 0xc001c68470, {0x3daa130, ...}, ...)
	/root/go/pkg/mod/github.com/cometbft/[email protected]/node/node.go:779 +0x597
github.com/zeta-chain/zetacore/server.startInProcess(_, {{0x0, 0x0, 0x0}, {0x3dd4ac0, 0xc001b39b60}, 0x0, {0xc001b702c0, 0x10}, {0x3dc6458, ...}, ...}, ...)
	/go/src/github.com/zeta-chain/node/server/start.go:380 +0xf47
github.com/zeta-chain/zetacore/server.StartCmd.func2(0xc001a42f00?, {0xc001b394a0?, 0x0?, 0x3?})
	/go/src/github.com/zeta-chain/node/server/start.go:164 +0x2a5
github.com/spf13/cobra.(*Command).execute(0xc001a42f00, {0xc001b39410, 0x3, 0x3})
	/root/go/pkg/mod/github.com/spf13/[email protected]/command.go:940 +0x862
github.com/spf13/cobra.(*Command).ExecuteC(0xc001782c00)
	/root/go/pkg/mod/github.com/spf13/[email protected]/command.go:1068 +0x3bd
github.com/spf13/cobra.(*Command).Execute(...)
	/root/go/pkg/mod/github.com/spf13/[email protected]/command.go:992
github.com/spf13/cobra.(*Command).ExecuteContext(...)
	/root/go/pkg/mod/github.com/spf13/[email protected]/command.go:985
github.com/cosmos/cosmos-sdk/server/cmd.Execute(0x26bd600?, {0x0, 0x0}, {0xc001485460, 0x1a})
	/root/go/pkg/mod/github.com/cosmos/[email protected]/server/cmd/execute.go:36 +0x20f
main.main()
	/go/src/github.com/zeta-chain/node/cmd/zetacored/main.go:19 +0x35

Environment (please complete the following information):
ALL

[lumtis]

FYI We already defined default parameters. The issue is the param module that panic when reading a key for a value that has not been previously set. Preventing the panic prevents the chain halt: #1864