chore: bump Go to 1.26.3 and centralize CLI build in integration tests

- Bump go to 1.26.3 and update GoBaseImage accordingly
- Use go 1.25.0 for integration go test as lowest version for compatibility
- Move CLI build out of individual tests into shared buildOpenFeatureCLI
- Bump golangci-lint to v2.12.2 and fix linter issues
- Fix test/README.md and update new-generator.md

Signed-off-by: Roman Dmytrenko <rdmytrenko@gmail.com>

Author: erka

.github/workflows/pr-lint.yml

@@ -24,7 +24,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-go@v5
         with:
-          go-version-file: 'go.mod'
+          go-version-file: "go.mod"
       - name: Check Go formatting
         run: |
           unformatted=$(go fmt ./...)
@@ -48,4 +48,4 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v9
         with:
-          version: v2.7.1
+          version: v2.12.2

Makefile

@@ -19,6 +19,9 @@ help:
 	@echo "  fmt                      - Format Go code"
 	@echo "  ci                       - Run all CI checks locally (fmt, lint, test, verify-generate)"
 
+# Tool versions
+GOLANGCI_LINT_VERSION := v2.12.2
+
 # Build variables
 VERSION ?= $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 COMMIT ?= $(shell git rev-parse --short HEAD 2>/dev/null || echo "unknown")
@@ -105,7 +108,7 @@ lint:
 	@echo "Running golangci-lint..."
 	@if ! command -v golangci-lint &> /dev/null; then \
 		echo "Installing golangci-lint..."; \
-		go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.7.1; \
+		go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@$(GOLANGCI_LINT_VERSION); \
 	fi
 	@golangci-lint run
 	@echo "Linting completed successfully!"
@@ -115,7 +118,7 @@ lint-fix:
 	@echo "Running golangci-lint with auto-fix..."
 	@if ! command -v golangci-lint &> /dev/null; then \
 		echo "Installing golangci-lint..."; \
-		go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.7.1; \
+		go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@$(GOLANGCI_LINT_VERSION); \
 	fi
 	@golangci-lint run --fix
 	@echo "Linting with auto-fix completed successfully!"

go.mod

@@ -1,6 +1,6 @@
 module github.com/open-feature/cli
 
-go 1.25.0
+go 1.26.3
 
 require (
 	dagger.io/dagger v0.20.6

internal/generators/csharp/csharp.go

@@ -69,7 +69,7 @@ func toCSharpDict(value any) string {
 	for _, key := range keys {
 		val := assertedMap[key]
 
-		builder.WriteString(fmt.Sprintf(".Set(%q, %s)", key, formatNestedValue(val)))
+		fmt.Fprintf(&builder, ".Set(%q, %s)", key, formatNestedValue(val))
 	}
 	builder.WriteString(".Build())")
 

internal/generators/golang/golang.go

@@ -90,7 +90,7 @@ func toMapLiteral(value any) string {
 		}
 		val := assertedMap[key]
 
-		builder.WriteString(fmt.Sprintf(`%q: %s`, key, formatNestedValue(val)))
+		fmt.Fprintf(&builder, `%q: %s`, key, formatNestedValue(val))
 	}
 
 	builder.WriteString("}")

internal/generators/java/java.go

@@ -73,7 +73,7 @@ func toMapLiteral(value any) string {
 		}
 		val := assertedMap[key]
 
-		builder.WriteString(fmt.Sprintf("%q, %s", key, formatNestedValue(val)))
+		fmt.Fprintf(&builder, "%q, %s", key, formatNestedValue(val))
 	}
 	builder.WriteString(")")
 

internal/generators/python/python.go

@@ -98,7 +98,7 @@ func toPythonDict(value any) string {
 		}
 		val := assertedMap[key]
 
-		builder.WriteString(fmt.Sprintf(`%q: %s`, key, formatNestedValue(val)))
+		fmt.Fprintf(&builder, `%q: %s`, key, formatNestedValue(val))
 	}
 
 	builder.WriteString("}")

internal/manifest/compare.go

@@ -68,8 +68,7 @@ func getKnownFlagProperties() map[string]bool {
 
 	// Extract fields from BaseFlag struct
 	t := reflect.TypeFor[BaseFlag]()
-	for i := range t.NumField() {
-		field := t.Field(i)
+	for field := range t.Fields() {
 		jsonTag := field.Tag.Get("json")
 		if jsonTag != "" {
 			// Extract field name from json tag (e.g., "flagType,omitempty" -> "flagType")

internal/manifest/validate.go

@@ -199,12 +199,10 @@ func FormatValidationError(issues []ValidationError) string {
 		if flagType == "" {
 			flagType = "missing"
 		}
-		sb.WriteString(fmt.Sprintf(
-			"- flagType: %s\n  flagPath: %s\n  errors:\n    ~ %s\n  \tSuggestions:\n      \t- flagType: boolean\n      \t- defaultValue: true\n\n",
+		fmt.Fprintf(&sb, "- flagType: %s\n  flagPath: %s\n  errors:\n    ~ %s\n  \tSuggestions:\n      \t- flagType: boolean\n      \t- defaultValue: true\n\n",
 			flagType,
 			path,
-			strings.Join(entry.messages, "\n    ~ "),
-		))
+			strings.Join(entry.messages, "\n    ~ "))
 	}
 	return sb.String()
 }

renovate.json

@@ -5,9 +5,7 @@
     {
       "customType": "regex",
       "description": "Update the GoBaseImage constant when a newer golang Docker image is available",
-      "managerFilePatterns": [
-        "test/integration/integration.go"
-      ],
+      "managerFilePatterns": ["test/integration/integration.go"],
       "matchStrings": [
         "GoBaseImage = \"golang:(?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)-alpine\""
       ],
@@ -18,17 +16,32 @@
     {
       "customType": "regex",
       "description": "Update minimum Go version mentioned in README and CONTRIBUTING",
-      "managerFilePatterns": [
-        "README.md",
-        "CONTRIBUTING.md"
-      ],
+      "managerFilePatterns": ["README.md", "CONTRIBUTING.md"],
       "matchStrings": [
         "Go >= (?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)",
         "Go (?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?) or later"
       ],
       "depNameTemplate": "go",
       "datasourceTemplate": "golang-version",
       "extractVersionTemplate": "^(?<version>\\d+\\.\\d+)"
+    },
+    {
+      "customType": "regex",
+      "managerFilePatterns": ["Makefile"],
+      "matchStrings": [
+        "GOLANGCI_LINT_VERSION\\s*:?=\\s*(?<currentValue>v?\\d+\\.\\d+\\.\\d+)"
+      ],
+      "depNameTemplate": "golangci/golangci-lint",
+      "datasourceTemplate": "github-releases"
+    },
+    {
+      "customType": "regex",
+      "managerFilePatterns": [".github/workflows/pr-lint.yml"],
+      "matchStrings": [
+        "uses:\\s*golangci/golangci-lint-action@v\\d+[\\s\\S]*?version:\\s*(?<currentValue>v?\\d+\\.\\d+\\.\\d+)"
+      ],
+      "depNameTemplate": "golangci/golangci-lint",
+      "datasourceTemplate": "github-releases"
     }
   ],
   "packageRules": [
@@ -37,6 +50,10 @@
       "matchDatasources": ["docker", "golang-version"],
       "matchPackageNames": ["golang", "go"],
       "groupName": "go toolchain"
+    },
+    {
+      "matchDepNames": ["golangci/golangci-lint"],
+      "groupName": "golangci-lint"
     }
   ]
 }