Fix incorrect vendored detections (#36508)

Fixes: https://github.com/go-gitea/gitea/issues/22618

`go-enry`'s `IsVendor` function marks git paths (`.gitignore`,
`.gitattributes`, `.gitmodules`), github/gitea paths (`.github/`,
`.gitea/`) as "vendored" for GitHub Linguist language statistics. This
causes these files to incorrectly display the "Vendored" tag in diff
views.

Override `go-enry`'s detection for these specific cases while preserving
its behavior for actual vendor directories.

---------

Signed-off-by: silverwind <me@silverwind.io>
Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: silverwind <115237+silverwind@users.noreply.github.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

AGENTS.md

@@ -1,7 +1,10 @@
 # Instructions for agents
 
 - Use `make help` to find available development targets
-- Before committing go code changes, run `make fmt`
+- Use the latest Golang stable release when working on Go code
+- Use the latest Node.js LTS release when working on TypeScript code
+- Before committing `.go` changes, run `make fmt` to format, and run `make lint-go` to lint
+- Before committing `.ts` changes, run `make lint-js` to lint
 - Before committing `go.mod` changes, run `make tidy`
 - Before committing new `.go` files, add the current year into the copyright header
-- Before committing files, removed any trailing whitespace
+- Before committing any files, remove all trailing whitespace from source code lines

modules/analyze/vendor.go

@@ -4,10 +4,28 @@
 package analyze
 
 import (
+	"path"
+	"strings"
+
 	"github.com/go-enry/go-enry/v2"
 )
 
-// IsVendor returns whether or not path is a vendor path.
-func IsVendor(path string) bool {
-	return enry.IsVendor(path)
+// IsVendor returns whether the path is a vendor path.
+// It uses go-enry's IsVendor function but overrides its detection for certain
+// special cases that shouldn't be marked as vendored in the diff view.
+func IsVendor(treePath string) bool {
+	if !enry.IsVendor(treePath) {
+		return false
+	}
+
+	// Override detection for single files
+	basename := path.Base(treePath)
+	switch basename {
+	case ".gitignore", ".gitattributes", ".gitmodules":
+		return false
+	}
+	if strings.HasPrefix(treePath, ".github/") || strings.HasPrefix(treePath, ".gitea/") {
+		return false
+	}
+	return true
 }

modules/analyze/vendor_test.go

@@ -14,6 +14,7 @@ func TestIsVendor(t *testing.T) {
 		path string
 		want bool
 	}{
+		// Original go-enry test cases
 		{"cache/", true},
 		{"random/cache/", true},
 		{"cache", false},
@@ -34,6 +35,14 @@ func TestIsVendor(t *testing.T) {
 		{"a/docs/_build/", true},
 		{"a/dasdocs/_build-vsdoc.js", true},
 		{"a/dasdocs/_build-vsdoc.j", false},
+
+		// Override: Git/GitHub/Gitea-related paths should NOT be detected as vendored
+		{".gitignore", false},
+		{".gitattributes", false},
+		{".gitmodules", false},
+		{"src/.gitignore", false},
+		{".github/workflows/ci.yml", false},
+		{".gitea/workflows/ci.yml", false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.path, func(t *testing.T) {