docs: final review of light client developer guide (backport #3081) (#…

…3130)

* docs: final review of light client developer guide (#3081)

Co-authored-by: crodriguezvega <[email protected]>
(cherry picked from commit fdadae5)

* fixed alignment

* fixed alignment

---------

Co-authored-by: tmsdkeys <[email protected]>
Co-authored-by: Carlos Rodriguez <[email protected]>

docs/.vuepress/config.js

@@ -348,49 +348,44 @@ module.exports = {
                   path: "/ibc/light-clients/overview.html",
                 },
                 {
-                  title: "ClientState",
+                  title: "Client State interface",
                   directory: false,
                   path: "/ibc/light-clients/client-state.html",
                 },
                 {
-                  title: "ConsensusState",
+                  title: "Consensus State interface",
                   directory: false,
                   path: "/ibc/light-clients/consensus-state.html",
                 },
                 {
-                  title: "Setup",
-                  directory: false,
-                  path: "/ibc/light-clients/setup.html",
-                },
-                {
-                  title: "Updates Handling",
+                  title: "Handling Updates and Misbehaviour",
                   directory: false,
-                  path: "/ibc/light-clients/update.html",
+                  path: "/ibc/light-clients/updates-and-misbehaviour.html",
                 },
                 {
-                  title: "Misbehaviour Handling",
+                  title: "Handling Upgrades",
                   directory: false,
-                  path: "/ibc/light-clients/misbehaviour.html",
+                  path: "/ibc/light-clients/upgrades.html",
                 },
                 {
                   title: "Existence/Non-Existence Proofs",
                   directory: false,
                   path: "/ibc/light-clients/proofs.html",
                 },
                 {
-                  title: "Upgrades Handling",
+                  title: "Handling Proposals",
                   directory: false,
-                  path: "/ibc/light-clients/upgrade.html",
+                  path: "/ibc/light-clients/proposals.html",
                 },
                 {
-                  title: "Proposal Handling",
+                  title: "Handling Genesis",
                   directory: false,
-                  path: "/ibc/light-clients/proposal.html",
+                  path: "/ibc/light-clients/genesis.html",
                 },
                 {
-                  title: "Genesis Handling",
+                  title: "Setup",
                   directory: false,
-                  path: "/ibc/light-clients/genesis.html",
+                  path: "/ibc/light-clients/setup.html",
                 },
               ]
             },

docs/architecture/adr-001-coin-source-tracing.md

@@ -114,7 +114,7 @@ trace the token back to the originating chain, as specified on ICS20.
 
 The new proposed format will be the following:
 
-```golang
+```go
 ibcDenom = "ibc/" + hash(trace path + "/" + base denom)
 ```
 
@@ -133,7 +133,7 @@ message DenomTrace {
 
 The `IBCDenom` function constructs the `Coin` denomination used when creating the ICS20 fungible token packet data:
 
-```golang
+```go
 // Hash returns the hex bytes of the SHA256 hash of the DenomTrace fields using the following formula:
 //
 // hash = sha256(tracePath + "/" + baseDenom)
@@ -157,7 +157,7 @@ In order to retrieve the trace information from an IBC denomination, a lookup ta
 added to the `ibc-transfer` module. These values need to also be persisted between upgrades, meaning
 that a new `[]DenomTrace` `GenesisState` field state needs to be added to the module:
 
-```golang
+```go
 // GetDenomTrace retrieves the full identifiers trace and base denomination from the store.
 func (k Keeper) GetDenomTrace(ctx Context, denomTraceHash []byte) (DenomTrace, bool) {
   store := ctx.KVStore(k.storeKey)
@@ -188,14 +188,14 @@ func (k Keeper) SetDenomTrace(ctx Context, denomTrace DenomTrace) {
 The `MsgTransfer` will validate that the `Coin` denomination from the `Token` field contains a valid
 hash, if the trace info is provided, or that the base denominations matches:
 
-```golang
+```go
 func (msg MsgTransfer) ValidateBasic() error {
   // ...
   return ValidateIBCDenom(msg.Token.Denom)
 }
 ```
 
-```golang
+```go
 // ValidateIBCDenom validates that the given denomination is either:
 //
 //  - A valid base denomination (eg: 'uatom')
@@ -226,7 +226,7 @@ The denomination trace info only needs to be updated when token is received:
 - Receiver is **source** chain: The receiver created the token and must have the trace lookup already stored (if necessary _ie_ native token case wouldn't need a lookup).
 - Receiver is **not source** chain: Store the received info. For example, during step 1, when chain `B` receives `transfer/channelToA/denom`.
 
-```golang
+```go
 // SendTransfer
 // ...
 
@@ -245,7 +245,7 @@ if types.SenderChainIsSource(sourcePort, sourceChannel, fullDenomPath) {
 //...
 ```
 
-```golang
+```go
 // DenomPathFromHash returns the full denomination path prefix from an ibc denom with a hash
 // component.
 func (k Keeper) DenomPathFromHash(ctx sdk.Context, denom string) (string, error) {
@@ -266,7 +266,7 @@ func (k Keeper) DenomPathFromHash(ctx sdk.Context, denom string) (string, error)
 ```
 
 
-```golang
+```go
 // OnRecvPacket
 // ...
 
@@ -322,7 +322,7 @@ return k.bankKeeper.SendCoinsFromModuleToAccount(
 )
 ```
 
-```golang
+```go
 func NewDenomTraceFromRawDenom(denom string) DenomTrace{
   denomSplit := strings.Split(denom, "/")
   trace := ""

docs/dev/go-style-guide.md

@@ -71,7 +71,7 @@ Perhaps more key for code readability than good commenting is having the right s
 - Use [goimports](https://godoc.org/golang.org/x/tools/cmd/goimports).
 - Separate imports into blocks: one for the standard lib, one for external libs and one for application libs. For example:
 
-	```golang
+	```go
 	import (
 		// standard library imports
 		"fmt"
@@ -105,7 +105,7 @@ Perhaps more key for code readability than good commenting is having the right s
 - Panic is appropriate when an internal invariant of a system is broken, while all other cases (in particular, incorrect or invalid usage) should return errors.
 - Error messages should be formatted as following:
 
-	```golang
+	```go
 	sdkerrors.Wrapf(
 		<most specific error type possible>,
 		"<optional text description ended by colon and space>expected %s, got %s",

docs/ibc/integration.md

@@ -16,7 +16,7 @@ Integrating the IBC module to your SDK-based application is straighforward. The
 
 - Add required modules to the `module.BasicManager`
 - Define additional `Keeper` fields for the new modules on the `App` type
-- Add the module's `StoreKeys` and initialize their `Keepers`
+- Add the module's `StoreKey`s and initialize their `Keeper`s
 - Set up corresponding routers and routes for the `ibc` module
 - Add the modules to the module `Manager`
 - Add modules to `Begin/EndBlockers` and `InitGenesis`
@@ -28,10 +28,10 @@ The first step is to add the following modules to the `BasicManager`: `x/capabil
 and `x/ibc-transfer`. After that, we need to grant `Minter` and `Burner` permissions to
 the `ibc-transfer` `ModuleAccount` to mint and burn relayed tokens.
 
-### Integrating Light Clients
+### Integrating light clients
 
 > Note that from v7 onwards, all light clients have to be explicitly registered in a chain's app.go and follow the steps listed below. 
-  This is in contrast to earlier versions of ibc-go when 07-tendermint and 06-solomachine were added out of the box.
+  This is in contrast to earlier versions of ibc-go when `07-tendermint` and `06-solomachine` were added out of the box.
 
 All light clients must be registered with `module.BasicManager` in a chain's app.go file.
 
@@ -40,9 +40,9 @@ The following code example shows how to register the existing `ibctm.AppModuleBa
 ```diff
 
 import (
-    ...
-+    ibctm "github.com/cosmos/ibc-go/v6/modules/light-clients/07-tendermint"
-    ...
+  ...
++ ibctm "github.com/cosmos/ibc-go/v6/modules/light-clients/07-tendermint"
+  ...
 )
 
 // app.go
@@ -55,14 +55,15 @@ var (
     transfer.AppModuleBasic{}, // i.e ibc-transfer module
 
     // register light clients on IBC
-+    ibctm.AppModuleBasic{},
++   ibctm.AppModuleBasic{},
   )
 
   // module account permissions
   maccPerms = map[string][]string{
     // other module accounts permissions
     // ...
     ibctransfertypes.ModuleName:    {authtypes.Minter, authtypes.Burner},
+  }
 )
 ```
 

docs/ibc/light-clients/client-state.md

@@ -4,7 +4,7 @@ order: 2
 
 # Implementing the `ClientState` interface
 
-Learn how to implement the [`ClientState`](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/exported/client.go#L40) interface.
+Learn how to implement the [`ClientState`](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/exported/client.go#L40) interface. This list of methods described here does not include all methods of the interface. Some methods are explained in detail in the relevant sections of the guide.
 
 ## `ClientType` method
 
@@ -18,27 +18,27 @@ The format is created as follows: `ClientType-{N}` where `{N}` is the unique glo
 ## `Validate` method
 
 `Validate` should validate every client state field and should return an error if any value is invalid. The light client
-implementer is in charge of determining which checks are required. See the [tendermint light client implementation](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/light-clients/07-tendermint/types/client_state.go#L101) as a reference.
+implementer is in charge of determining which checks are required. See the [Tendermint light client implementation](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/light-clients/07-tendermint/types/client_state.go#L101) as a reference.
 
 ## `Status` method
 
 `Status` must return the status of the client.
 
 - An `Active` status indicates that clients are allowed to process packets.
-- A `Frozen` status indicates that a client is not allowed to be used.
-- An `Expired` status indicates that a client is not allowed to be used.
+- A `Frozen` status indicates that misbehaviour was detected in the counterparty chain and the client is not allowed to be used.
+- An `Expired` status indicates that a client is not allowed to be used because it was not updated for longer than the trusting period.
 - An `Unknown` status indicates that there was an error in determining the status of a client.
 
-All possible Status types can be found [here](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/exported/client.go#L26-L36).
+All possible `Status` types can be found [here](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/exported/client.go#L26-L36).
 
-This field is returned by the gRPC [QueryClientStatusResponse](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/02-client/types/query.pb.go#L665) endpoint.
+This field is returned in the response of the gRPC [`ibc.core.client.v1.Query/ClientStatus`](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/02-client/types/query.pb.go#L665) endpoint.
 
 ## `ZeroCustomFields` method
 
 `ZeroCustomFields` should return a copy of the light client with all client customizable fields with their zero value. It should not mutate the fields of the light client.
 This method is used when [scheduling upgrades](https://github.com/cosmos/ibc-go/blob/v6.0.0/modules/core/02-client/keeper/proposal.go#L89). Upgrades are used to upgrade chain specific fields. 
-In the tendermint case, this may be the chainID or the unbonding period.
-For more information about client upgrades see [the developer guide](../upgrades/developer-guide.md).
+In the tendermint case, this may be the chain ID or the unbonding period.
+For more information about client upgrades see the [Handling upgrades](./upgrades.md) section.
 
 ## `GetTimestampAtHeight` method
 
@@ -54,22 +54,22 @@ Clients may also store any necessary client-specific metadata.
 
 ## `VerifyMembership` method
 
-`VerifyMembership` must verify the existence of a value at a given CommitmentPath at the specified height. For more information about membership proofs
-see [the proof docs](./proofs.md).
+`VerifyMembership` must verify the existence of a value at a given commitment path at the specified height. For more information about membership proofs
+see the [Existence and non-existence proofs section](./proofs.md).
 
 ## `VerifyNonMembership` method
 
-`VerifyNonMembership` must verify the absence of a value at a given CommitmentPath at a specified height. For more information about non membership proofs
-see [the proof docs](./proofs.md).
+`VerifyNonMembership` must verify the absence of a value at a given commitment path at a specified height. For more information about non-membership proofs
+see the [Existence and non-existence proofs section](./proofs.md).
 
 ## `VerifyClientMessage` method
 
-VerifyClientMessage must verify a ClientMessage. A ClientMessage could be a Header, Misbehaviour, or batch update.
-It must handle each type of ClientMessage appropriately. Calls to CheckForMisbehaviour, UpdateState, and UpdateStateOnMisbehaviour
-will assume that the content of the ClientMessage has been verified and can be trusted. An error should be returned
+`VerifyClientMessage` must verify a `ClientMessage`. A `ClientMessage` could be a `Header`, `Misbehaviour`, or batch update.
+It must handle each type of `ClientMessage` appropriately. Calls to `CheckForMisbehaviour`, `UpdateState`, and `UpdateStateOnMisbehaviour`
+will assume that the content of the `ClientMessage` has been verified and can be trusted. An error should be returned
 if the ClientMessage fails to verify.
 
 ## `CheckForMisbehaviour` method
 
-Checks for evidence of a misbehaviour in Header or Misbehaviour type. It assumes the ClientMessage
+Checks for evidence of a misbehaviour in `Header` or `Misbehaviour` type. It assumes the `ClientMessage`
 has already been verified.

docs/ibc/light-clients/consensus-state.md

@@ -4,7 +4,9 @@ order: 3
 
 # Implementing the `ConsensusState` interface
 
-A `ConsensusState` is the snapshot of the counterparty chain that an IBC client uses to verify proofs (e.g. a block). The further development of multiple types of IBC light clients and the difficulties presented by this generalization problem (see [ADR-006](https://github.com/cosmos/ibc-go/blob/main/docs/architecture/adr-006-02-client-refactor.md) for more information about this historical context) led to the design decision of each client keeping track of and set its own `ClientState` and `ConsensusState`, as well as the simplification of client `ConsensusState` updates through the generalized `ClientMessage` interface.
+A `ConsensusState` is the snapshot of the counterparty chain, that an IBC client uses to verify proofs (e.g. a block). 
+
+The further development of multiple types of IBC light clients and the difficulties presented by this generalization problem (see [ADR-006](https://github.com/cosmos/ibc-go/blob/main/docs/architecture/adr-006-02-client-refactor.md) for more information about this historical context) led to the design decision of each client keeping track of and set its own `ClientState` and `ConsensusState`, as well as the simplification of client `ConsensusState` updates through the generalized `ClientMessage` interface.
 
 The below [`ConsensusState`](https://github.com/cosmos/ibc-go/blob/main/modules/core/exported/client.go#L134) interface is a generalized interface for the types of information a `ConsensusState` could contain. For a reference `ConsensusState` implementation, please see the [Tendermint light client `ConsensusState`](https://github.com/cosmos/ibc-go/blob/main/modules/light-clients/07-tendermint/consensus_state.go).
 

docs/ibc/light-clients/genesis.md

@@ -1,18 +1,18 @@
 <!--
-order: 10
+order: 8
 -->
 
-# Genesis Metadata
+# Genesis metadata
 
 Learn how to implement the `ExportMetadata` interface {synopsis}
 
-## Pre-requisite Readings
+## Pre-requisite readings
 
 - [Cosmos SDK module genesis](https://docs.cosmos.network/v0.47/building-modules/genesis) {prereq}
 
 `ClientState` instances are provided their own isolated and namespaced client store upon initialisation. `ClientState` implementations may choose to store any amount of arbitrary metadata in order to verify counterparty consensus state and perform light client updates correctly. 
 
-The `ExportMetadata` method of the `ClientState` interface provides light client modules with the ability to persist metadata in genesis exports. 
+The `ExportMetadata` method of the [`ClientState` interface](https://github.com/cosmos/ibc-go/blob/e650be91614ced7be687c30eb42714787a3bbc59/modules/core/exported/client.go) provides light client modules with the ability to persist metadata in genesis exports. 
 
 ```go
 ExportMetadata(clientStore sdk.KVStore) []GenesisMetadata
@@ -22,14 +22,15 @@ ExportMetadata(clientStore sdk.KVStore) []GenesisMetadata
 
 ```go
 type GenesisMetadata interface {
-	// return store key that contains metadata without clientID-prefix
-	GetKey() []byte
-	// returns metadata value
-	GetValue() []byte
+  // return store key that contains metadata without clientID-prefix
+  GetKey() []byte
+  // returns metadata value
+  GetValue() []byte
 }
 ```
 
-This allows `ClientState` instances to retrieve and export any number of key-value pairs which are maintained within the store in their raw `[]byte` form. 
+This allows `ClientState` instances to retrieve and export any number of key-value pairs which are maintained within the store in their raw `[]byte` form.
+
 When a chain is started with a `genesis.json` file which contains `ClientState` metadata (for example, when performing manual upgrades using an exported `genesis.json`) the `02-client` submodule of core IBC will handle setting the key-value pairs within their respective client stores. [See `02-client` `InitGenesis`](https://github.com/cosmos/ibc-go/blob/02-client-refactor-beta1/modules/core/02-client/genesis.go#L18-L22).
 
-Please refer to the [`07-tendermint` implementation](https://github.com/cosmos/ibc-go/blob/02-client-refactor-beta1/modules/light-clients/07-tendermint/genesis.go#L12) as an example.
+Please refer to the [Tendermint light client implementation](https://github.com/cosmos/ibc-go/blob/02-client-refactor-beta1/modules/light-clients/07-tendermint/genesis.go#L12) for an example.