Fix Issues of golangci-lint (#37)

* Add golangci-lint config file, and fix lint issues.

Signed-off-by: txaty <[email protected]>

.golangci.yml

@@ -0,0 +1,150 @@
+linters-settings:
+  gci:
+    local-prefixes: github.com/txaty/go-merkletree
+  dupl:
+    threshold: 100
+  errorlint:
+    errorf: true
+  errcheck:
+    check-type-assertions: true
+    check-blank: true
+  exhaustive:
+    check-generated: false
+    default-signifies-exhaustive: false
+  funlen:
+    lines: 65
+    statements: 40
+  gocognit:
+    min-complexity: 15
+  gocyclo:
+    min-complexity: 10
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - dupImport
+      - unnecessaryBlock
+  gofumpt:
+    extra-rules: true
+  gomnd:
+    settings:
+      mnd:
+        checks:
+          - argument
+          - case
+          - condition
+          - operation
+          - return
+  govet:
+    check-shadowing: true
+  misspell:
+    locale: US
+  nestif:
+    min-complexity: 4
+  nolintlint:
+    require-explanation: true
+    require-specific: true
+
+linters:
+  disable-all: true
+  enable:
+    - asasalint
+    - asciicheck
+    - bidichk
+    - bodyclose
+    - containedctx
+    - contextcheck
+    - cyclop
+    - decorder
+    - depguard
+    - dogsled
+    - dupl
+    - durationcheck
+    - errcheck
+    - errorlint
+    - exhaustive
+    - exportloopref
+    - forbidigo
+    - funlen
+    - gci
+    - gochecknoglobals
+    - gochecknoinits
+    - gocognit
+    - goconst
+    - gocritic
+    - gocyclo
+    - godot
+    - godox
+    - goerr113
+    - gofmt
+    - gofumpt
+    - goimports
+    - gomnd
+    - gomodguard
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - makezero
+    - misspell
+    - nakedret
+    - nestif
+    - nlreturn
+    - noctx
+    - nolintlint
+    - paralleltest
+    - predeclared
+    - revive
+    - rowserrcheck
+    - sloglint
+    - sqlclosecheck
+    - staticcheck
+    - stylecheck
+    - tparallel
+    - thelper
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - wastedassign
+    - wsl
+    - whitespace
+    - goheader
+    - prealloc
+    - wrapcheck
+    - zerologlint
+
+disable:
+  - testpackage
+
+issues:
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - cyclop
+        - depguard
+        - dupl
+        - forbidigo
+        - funlen
+        - gocognit
+        - gocritic
+        - gocyclo
+        - goerr113
+        - gosec
+        - nestif
+        - nlreturn
+        - paralleltest
+        - unparam
+        - wsl
+
+run:
+  skip-dirs:
+    - docs

default_hash.go

@@ -25,14 +25,17 @@ package merkletree
 import "crypto/sha256"
 
 // sha256Digest is the reusable digest for DefaultHashFunc.
-// It is used to avoid creating a new hash digest for every call to DefaultHashFunc.
+// It is used to avoid creating a new hash digest for every call to DefaultHashFunc and reduce memory allocations.
+//
+//nolint:gochecknoglobals // Ignoring this linting error as this has to be a global variable.
 var sha256Digest = sha256.New()
 
 // DefaultHashFunc is the default hash function used when no user-specified hash function is provided.
 // It implements the SHA256 hash function and reuses sha256Digest to reduce memory allocations.
 func DefaultHashFunc(data []byte) ([]byte, error) {
 	defer sha256Digest.Reset()
 	sha256Digest.Write(data)
+
 	return sha256Digest.Sum(make([]byte, 0, sha256Digest.Size())), nil
 }
 
@@ -42,5 +45,6 @@ func DefaultHashFunc(data []byte) ([]byte, error) {
 func DefaultHashFuncParallel(data []byte) ([]byte, error) {
 	digest := sha256.New()
 	digest.Write(data)
+
 	return digest.Sum(make([]byte, 0, digest.Size())), nil
 }

leaf.go

@@ -22,7 +22,11 @@
 
 package merkletree
 
-import "golang.org/x/sync/errgroup"
+import (
+	"fmt"
+
+	"golang.org/x/sync/errgroup"
+)
 
 // computeLeafNodes compute the leaf nodes from the data blocks.
 func (m *MerkleTree) computeLeafNodes(blocks []DataBlock) ([][]byte, error) {
@@ -32,11 +36,13 @@ func (m *MerkleTree) computeLeafNodes(blocks []DataBlock) ([][]byte, error) {
 		disableLeafHashing = m.DisableLeafHashing
 		err                error
 	)
+
 	for i := 0; i < m.NumLeaves; i++ {
 		if leaves[i], err = dataBlockToLeaf(blocks[i], hashFunc, disableLeafHashing); err != nil {
 			return nil, err
 		}
 	}
+
 	return leaves, nil
 }
 
@@ -50,22 +56,28 @@ func (m *MerkleTree) computeLeafNodesParallel(blocks []DataBlock) ([][]byte, err
 		disableLeafHashing = m.DisableLeafHashing
 		eg                 = new(errgroup.Group)
 	)
+
 	numRoutines = min(numRoutines, lenLeaves)
+
 	for startIdx := 0; startIdx < numRoutines; startIdx++ {
 		startIdx := startIdx
+
 		eg.Go(func() error {
 			var err error
 			for i := startIdx; i < lenLeaves; i += numRoutines {
 				if leaves[i], err = dataBlockToLeaf(blocks[i], hashFunc, disableLeafHashing); err != nil {
 					return err
 				}
 			}
+
 			return nil
 		})
 	}
+
 	if err := eg.Wait(); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("computeLeafNodesParallel: %w", err)
 	}
+
 	return leaves, nil
 }
 
@@ -74,13 +86,16 @@ func (m *MerkleTree) computeLeafNodesParallel(blocks []DataBlock) ([][]byte, err
 func dataBlockToLeaf(block DataBlock, hashFunc TypeHashFunc, disableLeafHashing bool) ([]byte, error) {
 	blockBytes, err := block.Serialize()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("dataBlockToLeaf: %w", err)
 	}
+
 	if disableLeafHashing {
 		// copy the value so that the original byte slice is not modified
 		leaf := make([]byte, len(blockBytes))
 		copy(leaf, blockBytes)
+
 		return leaf, nil
 	}
+
 	return hashFunc(blockBytes)
 }