add ci linting and fix existing lint errors

.github/workflows/go.yml

@@ -40,11 +40,16 @@ jobs:
       - name: Test
         run: |
           go test ./... -race
-      
+
       - name: Coverage
         run: |
           make coverage-diff
-
+
+      - name: Lint
+        uses: golangci/golangci-lint-action@08e2f20817b15149a52b5b3ebe7de50aff2ba8c5
+        with:
+          args: --timeout=5m
+
   vulncheck:
     name: Vulnerability Check
     runs-on: ubuntu-latest
@@ -56,12 +61,12 @@ jobs:
 
       - name: Check out code into the Go module directory
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-  
+
       - name: go mod package cache
         uses: actions/cache@1bd1e32a3bdc45362d1e726936510720a7c30a57 # v4.2.0
         with:
           path: ~/go/pkg/mod
           key: ${{ runner.os }}-go-122-${{ hashFiles('tests/go.mod') }}
 
-      - name: govulncheck 
-        uses: golang/govulncheck-action@7da72f730e37eeaad891fcff0a532d27ed737cd4 # v1
+      - name: govulncheck
+        uses: golang/govulncheck-action@7da72f730e37eeaad891fcff0a532d27ed737cd4 # v1

CHANGELOG.md

@@ -10,6 +10,8 @@ Canonical reference for changes, improvements, and bugfixes for mql.
 * feat: add support for table column mapping by @dlclark in [[PR](https://github.com/hashicorp/mql/pull/45)]
 * feat: add support for table column name from struct tags @terminalfi in [[PR](https://github.com/hashicorp/mql/pull/50)]
 * chore: update deps by @jimlambrt in [[PR](https://github.com/hashicorp/mql/pull/54)]
+* ci: run linter during PR build in [[PR](https://github.com/hashicorp/mql/pull/52)]
+* chore: fix various lint issues in [[PR](https://github.com/hashicorp/mql/pull/52)]
 
 ## 0.1.4 (2024/05/14)
 

expr.go

@@ -166,9 +166,8 @@ func (l *logicalExpr) String() string {
 // root will return the root of the expr tree
 func root(lExpr *logicalExpr, raw string) (expr, error) {
 	const op = "mql.root"
-	switch {
 	// intentionally not checking raw, since can be an empty string
-	case lExpr == nil:
+	if lExpr == nil {
 		return nil, fmt.Errorf("%s: %w (missing expression)", op, ErrInvalidParameter)
 	}
 	logicalOp := lExpr.logicalOp

lex.go

@@ -123,24 +123,24 @@ WriteToBuf:
 	// keep reading runes into the buffer until we encounter eof or the final delimiter.
 	for {
 		r = l.read()
-		switch {
-		case r == eof:
+		switch r {
+		case eof:
 			break WriteToBuf
-		case r == backslash:
+		case backslash:
 			nextR := l.read()
-			switch {
-			case nextR == eof:
+			switch nextR {
+			case eof:
 				tokenBuf.WriteRune(r)
 				return nil, fmt.Errorf("%s: %w in %q", op, ErrInvalidTrailingBackslash, tokenBuf.String())
-			case nextR == backslash:
+			case backslash:
 				tokenBuf.WriteRune(nextR)
-			case nextR == delimiter:
+			case delimiter:
 				tokenBuf.WriteRune(nextR)
 			default:
 				tokenBuf.WriteRune(r)
 				tokenBuf.WriteRune(nextR)
 			}
-		case r == delimiter: // end of the quoted string we're scanning
+		case delimiter: // end of the quoted string we're scanning
 			finalDelimiter = true
 			break WriteToBuf
 		default: // otherwise, write the rune into the keyword buffer
@@ -160,7 +160,7 @@ WriteToBuf:
 // orToken, andToken, containsToken
 func lexSymbolState(l *lexer) (lexStateFunc, error) {
 	const op = "mql.lexSymbolState"
-	panicIfNil(l, "lexSymbolState", "lexer")
+	panicIfNil(l, op, "lexer")
 	defer l.current.clear()
 
 ReadRunes:

parser.go

@@ -184,10 +184,10 @@ func (p *parser) parseComparisonExpr() (expr, error) {
 		case cmpExpr.value == nil && (p.currentToken.Type != stringToken && p.currentToken.Type != numberToken && p.currentToken.Type != symbolToken):
 			return nil, fmt.Errorf("%s: %w %q in: %q", op, ErrUnexpectedToken, p.currentToken.Value, p.raw)
 		case cmpExpr.value == nil:
-			switch {
-			case p.currentToken.Type == symbolToken:
+			switch p.currentToken.Type {
+			case symbolToken:
 				return nil, fmt.Errorf("%s: %w %s == %s (expected: %s or %s) in %q", op, ErrInvalidComparisonValueType, p.currentToken.Type, p.currentToken.Value, stringToken, numberToken, p.raw)
-			case p.currentToken.Type == stringToken, p.currentToken.Type == numberToken:
+			case stringToken, numberToken:
 				s := p.currentToken.Value
 				cmpExpr.value = &s
 			default:

validate.go

@@ -32,7 +32,7 @@ func fieldValidators(model reflect.Value, opt ...Option) (map[string]validator,
 		model.Kind() == reflect.Pointer && model.Elem().Kind() != reflect.Struct:
 		return nil, fmt.Errorf("%s: model must be a struct or a pointer to a struct: %w", op, ErrInvalidParameter)
 	}
-	var m reflect.Value = model
+	m := model
 	if m.Kind() != reflect.Struct {
 		m = model.Elem()
 	}