fix(store): handle nil end in cachekv/iterator (#12945)

Closes: #12661

Adds support for nil end semantics to iterators in cachekv store, addressing [this workaround](https://github.com/osmosis-labs/osmosis/blob/4176b287d48338870bfda3029bfa20a6e45ac126/osmoutils/store_helper.go#L37-L41).

Note that this has the effect of sorting the dirty cache into the BTree cache store in the bounds `[startIndex, end-of-cache-space]`

---

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- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
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Author: kocubinski

CHANGELOG.md

@@ -230,6 +230,7 @@ replace github.com/confio/ics23/go => github.com/cosmos/cosmos-sdk/ics23/go v0.8
 
 * (x/group) [#12888](https://github.com/cosmos/cosmos-sdk/pull/12888) Fix event propagation to the current context of `x/group` message execution `[]sdk.Result`.
 * (x/upgrade) [#12906](https://github.com/cosmos/cosmos-sdk/pull/12906) Fix upgrade failure by moving downgrade verification logic after store migration.
+* (store) [#12945](https://github.com/cosmos/cosmos-sdk/pull/12945) Fix nil end semantics in store/cachekv/iterator when iterating a dirty cache.
 
 ## [v0.46.0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.46.0) - 2022-07-26
 

store/cachekv/store.go

@@ -13,7 +13,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/store/tracekv"
 	"github.com/cosmos/cosmos-sdk/store/types"
 	"github.com/cosmos/cosmos-sdk/types/kv"
-	"github.com/tendermint/tendermint/libs/math"
 )
 
 // cValue represents a cached value.
@@ -279,7 +278,7 @@ const minSortSize = 1024
 // Constructs a slice of dirty items, to use w/ memIterator.
 func (store *Store) dirtyItems(start, end []byte) {
 	startStr, endStr := conv.UnsafeBytesToStr(start), conv.UnsafeBytesToStr(end)
-	if startStr > endStr {
+	if end != nil && startStr > endStr {
 		// Nothing to do here.
 		return
 	}
@@ -294,6 +293,7 @@ func (store *Store) dirtyItems(start, end []byte) {
 	// than just not having the cache.
 	if n < minSortSize {
 		for key := range store.unsortedCache {
+			// dbm.IsKeyInDomain is nil safe and returns true iff key is greater than start
 			if dbm.IsKeyInDomain(conv.UnsafeStrToBytes(key), start, end) {
 				cacheValue := store.cache[key]
 				unsorted = append(unsorted, &kv.Pair{Key: []byte(key), Value: cacheValue.value})
@@ -314,24 +314,18 @@ func (store *Store) dirtyItems(start, end []byte) {
 	// Now find the values within the domain
 	//  [start, end)
 	startIndex := findStartIndex(strL, startStr)
-	endIndex := findEndIndex(strL, endStr)
-
-	if endIndex < 0 {
-		endIndex = len(strL) - 1
-	}
 	if startIndex < 0 {
 		startIndex = 0
 	}
 
-	// Since we spent cycles to sort the values, we should process and remove a reasonable amount
-	// ensure start to end is at least minSortSize in size
-	// if below minSortSize, expand it to cover additional values
-	// this amortizes the cost of processing elements across multiple calls
-	if endIndex-startIndex < minSortSize {
-		endIndex = math.MinInt(startIndex+minSortSize, len(strL)-1)
-		if endIndex-startIndex < minSortSize {
-			startIndex = math.MaxInt(endIndex-minSortSize, 0)
-		}
+	var endIndex int
+	if end == nil {
+		endIndex = len(strL) - 1
+	} else {
+		endIndex = findEndIndex(strL, endStr)
+	}
+	if endIndex < 0 {
+		endIndex = len(strL) - 1
 	}
 
 	kvL := make([]*kv.Pair, 0)