refactor: streamline flattening logic and improve variable naming in tests & upgrade golangci-lint to V2

fix: update Go setup to use version from go.mod and enable latest check

fix: ensure Go setup action is correctly specified in CI workflow

fix: correct golangci-lint configuration file extension from .yml to .yaml

Author: developerkunal

.github/workflows/ci.yml

@@ -14,7 +14,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
+          go-version-file: go.mod
+          check-latest: true
       - name: Build
         run: make build
       - name: Test
@@ -27,11 +28,10 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
-      - name: Install golangci-lint
-        run: |
-          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.64.8
-      - name: Check golangci-lint version
-        run: golangci-lint --version
-      - name: Lint
-        run: make lint
+          go-version-file: go.mod
+          check-latest: true
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@4afd733a84b1f43292c63897423277bb7f4313a9 # pin@8.0.0
+        with:
+          version: latest
+          args: -v -c .golangci.yaml

.golangci.yaml

@@ -1,122 +1,135 @@
-# GolangCI-Lint v2.x configuration (clean, no deprecated options)
-# See: https://golangci-lint.run/usage/configuration/
-
-linters-settings:
-  gocyclo:
-    min-complexity: 15
-  dupl:
-    threshold: 100
-  errcheck:
-    check-type-assertions: true
-  staticcheck:
-    checks: [all]
-  revive:
-    confidence: 0.8
-    severity: warning
-    rules:
-      - name: var-naming
-      - name: indent-error-flow
-      - name: error-naming
-      - name: if-return
-      - name: import-shadowing
-      - name: range-val-address
-      - name: time-naming
-      - name: unexported-return
-      - name: unused-parameter
-      - name: unused-receiver
-      - name: var-declaration
-      - name: exported
-      - name: blank-imports
-      - name: context-as-argument
-      - name: context-keys-type
-      - name: error-strings
-      - name: error-return
-      - name: errorf
-      - name: function-length
-  gofmt:
-    simplify: true
-  misspell:
-    locale: US
-
+version: "2"
 run:
-  timeout: 5m
-  tests: true
-  issues-exit-code: 1
   modules-download-mode: readonly
+  issues-exit-code: 1
+  tests: true
   allow-parallel-runners: true
-
-issues:
-  exclude-dirs:
-    - dist
-    - vendor
-    - .git
-    - .github
-    - .vscode
-    - .idea
-    - node_modules
-    - testdata
-  exclude-files:
-    - ".*_gen.go$"
-    - ".*_mock.go$"
-  exclude-rules:
-    # Exclude test files from certain linting rules
-    - path: ".*_test\\.go$"
-      linters:
-        - dupl
-        - gocyclo
-        - revive
-    # Allow longer functions in tests
-    - path: ".*_test\\.go$"
-      text: "function-length"
-    # Allow high cyclomatic complexity in tests
-    - path: ".*_test\\.go$"
-      text: "cyclomatic complexity"
-
 linters:
   enable:
-    - govet
-    - errcheck
-    - staticcheck
-    - revive
-    - gofmt
-    - misspell
-    - gocyclo
     - dupl
+    - gocyclo
+    - misspell
+    - revive
   disable:
-    - godox
-    - lll
-    - funlen
-    - wsl
+    - asasalint
+    - bodyclose
+    - cyclop
+    - depguard
     - dogsled
+    - exhaustive
+    - forbidigo
+    - funlen
+    - gocognit
     - goconst
     - gocritic
+    - godox
+    - goheader
+    - goprintffuncname
     - gosec
-    - depguard
-    - unparam
+    - lll
     - nakedret
-    - prealloc
-    - exhaustive
     - nestif
-    - goprintffuncname
-    - gocognit
-    - cyclop
-    - bodyclose
-    - asasalint
     - nlreturn
     - noctx
-    - rowserrcheck
-    - stylecheck
-    - typecheck
-    - unused
-    - whitespace
-    - wrapcheck
-    - forbidigo
-    - gci
-    - goheader
     - nolintlint
     - paralleltest
+    - prealloc
+    - rowserrcheck
     - testpackage
     - thelper
     - tparallel
     - unconvert
+    - unparam
+    - unused
     - wastedassign
+    - whitespace
+    - wrapcheck
+    - wsl
+  settings:
+    dupl:
+      threshold: 100
+    errcheck:
+      check-type-assertions: true
+    gocyclo:
+      min-complexity: 15
+    misspell:
+      locale: US
+    revive:
+      confidence: 0.8
+      severity: warning
+      rules:
+        - name: var-naming
+        - name: indent-error-flow
+        - name: error-naming
+        - name: if-return
+        - name: import-shadowing
+        - name: range-val-address
+        - name: time-naming
+        - name: unexported-return
+        - name: unused-parameter
+        - name: unused-receiver
+        - name: var-declaration
+        - name: exported
+        - name: blank-imports
+        - name: context-as-argument
+        - name: context-keys-type
+        - name: error-strings
+        - name: error-return
+        - name: errorf
+        - name: function-length
+    staticcheck:
+      checks:
+        - all
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    rules:
+      - linters:
+          - dupl
+          - gocyclo
+          - revive
+        path: .*_test\.go$
+      - path: .*_test\.go$
+        text: function-length
+      - path: .*_test\.go$
+        text: cyclomatic complexity
+    paths:
+      - .*_gen.go$
+      - .*_mock.go$
+      - dist
+      - vendor
+      - .git
+      - .github
+      - .vscode
+      - .idea
+      - node_modules
+      - testdata
+      - third_party$
+      - builtin$
+      - examples$
+formatters:
+  enable:
+    - gofmt
+  settings:
+    gofmt:
+      simplify: true
+  exclusions:
+    generated: lax
+    paths:
+      - .*_gen.go$
+      - .*_mock.go$
+      - dist
+      - vendor
+      - .git
+      - .github
+      - .vscode
+      - .idea
+      - node_modules
+      - testdata
+      - third_party$
+      - builtin$
+      - examples$

internal/transform/flatten.go

@@ -80,16 +80,10 @@ func processDocumentFlattening(doc, root *yaml.Node, path string, opts FlattenOp
 	// Track component references before flattening to identify unused ones later
 	componentsBefore := extractComponentRefs(root)
 
-	changed := false
-
 	// First pass: flatten oneOf/anyOf/allOf with single refs
-	if processComponentsFlattening(root, path, result, &changed) {
-		changed = true
-	}
-
-	if processPathsFlattening(root, path, result, &changed) {
-		changed = true
-	}
+	changed := false
+	processComponentsFlattening(root, path, result, &changed)
+	processPathsFlattening(root, path, result, &changed)
 
 	// Second pass: flatten reference chains (optional, more aggressive)
 	if opts.FlattenResponses {
@@ -130,18 +124,16 @@ func flattenReferenceChains(root *yaml.Node, filePath string, result *FlattenRes
 	if len(refMap) == 0 {
 		return false
 	}
-
-	localChanged := false
-
 	// Flatten reference chains in components/schemas
-	if flattenSchemaReferences(root, refMap, filePath, result) {
-		localChanged = true
-	}
+	// Capture the result of the first flattening operation
+	schemaChanged := flattenSchemaReferences(root, refMap, filePath, result)
 
 	// Flatten reference chains in paths
-	if flattenPathReferences(root, refMap, filePath, result) {
-		localChanged = true
-	}
+	// Capture the result of the second flattening operation
+	pathChanged := flattenPathReferences(root, refMap, filePath, result)
+
+	// Combine the results: localChanged is true if either operation made a change
+	localChanged := schemaChanged || pathChanged
 
 	if localChanged {
 		*changed = true

internal/transform/flatten_test.go

@@ -159,12 +159,12 @@ paths:
 		t.Fatal("content is not a map[string]interface{}")
 	}
 
-	applicationJson, ok := content["application/json"].(map[string]interface{})
+	applicationJSON, ok := content["application/json"].(map[string]interface{})
 	if !ok {
 		t.Fatal("application/json is not a map[string]interface{}")
 	}
 
-	schema, ok := applicationJson["schema"].(map[string]interface{})
+	schema, ok := applicationJSON["schema"].(map[string]interface{})
 	if !ok {
 		t.Fatal("schema is not a map[string]interface{}")
 	}
@@ -441,12 +441,12 @@ paths:
 		t.Fatal("content is not a map[string]interface{}")
 	}
 
-	appJson, ok := content["application/json"].(map[string]interface{})
+	appJSON, ok := content["application/json"].(map[string]interface{})
 	if !ok {
 		t.Fatal("application/json is not a map[string]interface{}")
 	}
 
-	schema, ok := appJson["schema"].(map[string]interface{})
+	schema, ok := appJSON["schema"].(map[string]interface{})
 	if !ok {
 		t.Fatal("schema is not a map[string]interface{}")
 	}