update default cache dir

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/mholt/archiver/v4 v4.0.0-alpha.8
 	github.com/posener/complete v1.2.3
 	github.com/rogpeppe/go-internal v1.10.0
+	github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06
 	github.com/santhosh-tekuri/jsonschema/v5 v5.3.0
 	github.com/stretchr/testify v1.7.1
 	github.com/willabides/kongplete v0.3.0

go.sum

@@ -167,6 +167,8 @@ github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFR
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd/go.mod h1:hPqNNc0+uJM6H+SuU8sEs5K5IQeKccPqeSjfgcKGgPk=
+github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06 h1:OkMGxebDjyw0ULyrTYWeN0UNCCkmCWfjPnIA2W6oviI=
+github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06/go.mod h1:+ePHsJ1keEjQtpvf9HHw0f4ZeJ0TLRsxhunSI2hYJSs=
 github.com/santhosh-tekuri/jsonschema/v5 v5.3.0 h1:uIkTLo0AGRc8l7h5l9r+GcYi9qfVPt6lD4/bhmzfiKo=
 github.com/santhosh-tekuri/jsonschema/v5 v5.3.0/go.mod h1:FKdcjfQW6rpZSnxxUvEA5H/cDPdvJ/SZJQLWWXWGrZ0=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

internal/bindown/config.go

@@ -656,14 +656,48 @@ func NewConfig(ctx context.Context, cfgSrc string, noDefaultDirs bool) (*Config,
 		return cfg, nil
 	}
 	if cfg.Cache == "" {
-		cfg.Cache = filepath.Join(filepath.Dir(cfgSrc), ".cache")
+		cfg.Cache, err = findCacheDir(filepath.Dir(cfgSrc))
+		if err != nil {
+			return nil, err
+		}
 	}
 	if cfg.InstallDir == "" {
 		cfg.InstallDir = filepath.Join(filepath.Dir(cfgSrc), "bin")
 	}
 	return cfg, nil
 }
 
+// findCacheDir decides between .bindown and .cache for the cache directory to use when
+// none is specified. This is necessary because v4 mistakenly made .cache the default.
+// We want to use .bindown, but will revert to .cache if it is in .gitignore and .bindown
+// does not exist.
+func findCacheDir(cfgDir string) (string, error) {
+	// if .bindown exists, use it
+	bindownDir := filepath.Join(cfgDir, ".bindown")
+	info, err := os.Stat(bindownDir)
+	if err != nil && !os.IsNotExist(err) {
+		return "", err
+	}
+	if err == nil && info.IsDir() {
+		return bindownDir, nil
+	}
+	// if .cache is ignored by .gitignore, use it
+	cacheDir := filepath.Join(cfgDir, ".cache")
+	// When a dir is ignored with a trailing slash, we need to check if a file in that dir is ignored.
+	for _, dir := range []string{cacheDir, filepath.Join(cacheDir, "downloads")} {
+		var ignored bool
+		ignored, err = fileIsGitignored(dir)
+		if err != nil {
+			return "", err
+		}
+		if ignored {
+			return cacheDir, nil
+		}
+	}
+	// default to .bindown
+	return bindownDir, nil
+}
+
 func configFromHTTP(ctx context.Context, src string) (*Config, error) {
 	req, err := http.NewRequestWithContext(ctx, "GET", src, http.NoBody)
 	if err != nil {

internal/bindown/util.go

@@ -15,6 +15,7 @@ import (
 	"text/template"
 
 	"github.com/Masterminds/semver/v3"
+	ignore "github.com/sabhiram/go-gitignore"
 	"golang.org/x/exp/maps"
 	"golang.org/x/exp/slices"
 	"gopkg.in/yaml.v3"
@@ -228,3 +229,65 @@ func Unique[V comparable](vals, buf []V) []V {
 	}
 	return buf
 }
+
+// fileIsGitignored returns true if the file is ignored by a .gitignore file in the same directory or any parent
+// directory from the same git repo.
+func fileIsGitignored(filename string) (bool, error) {
+	dir := filepath.Dir(filename)
+	repoBase, err := gitRepo(dir)
+	if err != nil {
+		return false, err
+	}
+	if repoBase == "" {
+		return false, nil
+	}
+	for {
+		ignoreFile := filepath.Join(dir, ".gitignore")
+		var info os.FileInfo
+		info, err = os.Stat(ignoreFile)
+		if err != nil {
+			if !os.IsNotExist(err) {
+				return false, err
+			}
+		} else if info.Mode().Type().IsRegular() {
+			var ig *ignore.GitIgnore
+			ig, err = ignore.CompileIgnoreFile(ignoreFile)
+			if err != nil {
+				return false, err
+			}
+			var relFile string
+			relFile, err = filepath.Rel(dir, filename)
+			if err != nil {
+				return false, err
+			}
+			if ig.MatchesPath(relFile) {
+				return true, nil
+			}
+		}
+		if dir == repoBase {
+			break
+		}
+		dir = filepath.Dir(dir)
+	}
+	return false, nil
+}
+
+// gitRepo returns the path of the base git repo for a dir. Returns ""
+// if dir is not in a git repo.
+// Does not use git commands. Just checks for .git directory.
+func gitRepo(dir string) (string, error) {
+	dir = filepath.Clean(dir)
+	info, err := os.Stat(filepath.Join(dir, ".git"))
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return "", err
+		}
+	} else if info.IsDir() {
+		return dir, nil
+	}
+	parent := filepath.Dir(dir)
+	if parent == dir {
+		return "", nil
+	}
+	return gitRepo(parent)
+}