Show a warning when using wrong executable

This commit updates the 'wdcli' command to show a warning when using the
wrong executable.

internal/fsx/copy.go

@@ -12,7 +12,7 @@ var ErrCopySameFile = errors.New("src and dst must be different files")
 // CopyFile copies a file from src to dst.
 // When dst and src are the same file, returns ErrCopySameFile.
 func CopyFile(dst, src string) error {
-	if src == dst {
+	if SameFile(src, dst) {
 		return ErrCopySameFile
 	}
 
@@ -51,7 +51,7 @@ func CopyDirectory(dst, src string, onCopy func(dst, src string)) error {
 	// TODO: Allow copying in parallel? Maybe with a mutex?
 
 	// sanity checks
-	if src == dst {
+	if SameFile(src, dst) {
 		return ErrCopySameFile
 	}
 	if !IsDirectory(dst) {

internal/fsx/same.go

@@ -0,0 +1,87 @@
+package fsx
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// SameFile checks if path1 and path2 refer to the same file.
+// If both files exist, they are compared using [os.SameFile].
+// If both files do not exist, the paths are first compared syntactically and then via recursion on [filepath.Dir].
+func SameFile(path1, path2 string) bool {
+
+	// initial attempt: check if directly
+	same, certain := couldBeSameFile(path1, path2)
+	if certain {
+		return same
+	}
+
+	// second attempt: find the directory names and base paths
+	d1, n1 := filepath.Dir(path1), filepath.Base(path1)
+	d2, n2 := filepath.Dir(path2), filepath.Base(path2)
+
+	// if we have different file names (and they don't exist)
+	// we don't need to continue
+	if n1 != n2 {
+		return false
+	}
+
+	// compare the base names!
+	{
+		same, _ := couldBeSameFile(d1, d2)
+		return same
+	}
+}
+
+// couldBeSameFile checks if path1 might be the same as path2.
+//
+// If both files exist, compares using [os.SameFile].
+// Otherwise compares absolute paths using string comparison.
+//
+// same indicates if they might be the same file.
+// authorative indiciates if the result is authorative.
+func couldBeSameFile(path1, path2 string) (same, authorative bool) {
+	{
+		// stat both files
+		info1, err1 := os.Stat(path1)
+		info2, err2 := os.Stat(path2)
+
+		// both files exist => check using os.SameFile
+		// the result is always authorative
+		if err1 == nil && err2 == nil {
+			same = os.SameFile(info1, info2)
+			authorative = true
+			return
+		}
+
+		// only 1 file errored => they could be different
+		if (err1 == nil) != (err2 == nil) {
+			return
+		}
+
+		// only 1 file does not exist => they could be different
+		if os.IsNotExist(err1) != os.IsNotExist(err2) {
+			return
+		}
+	}
+
+	{
+		// resolve paths absolutely
+		rpath1, err1 := filepath.Abs(path1)
+		rpath2, err2 := filepath.Abs(path2)
+
+		// if either path could not be resolved absolutely
+		// fallback to just using clean!
+		if err1 != nil {
+			rpath1 = filepath.Clean(path1)
+		}
+		if err2 != nil {
+			rpath2 = filepath.Clean(path2)
+		}
+
+		// compare using strings
+		same = rpath1 == rpath2
+		authorative = same // positive result is authorative!
+		return
+	}
+}

internal/fsx/touch.go

@@ -5,7 +5,11 @@ import (
 	"time"
 )
 
-// Touch touches a file
+// Touch touches a file.
+// It is similar to the unix 'touch' command.
+//
+// If the file does not exist exists, it is created using [os.Create].
+// If the file does exist, it's access and modification times are updated to the current time.
 func Touch(path string) error {
 	_, err := os.Stat(path)
 	switch {

internal/fsx/type.go

@@ -1,17 +1,23 @@
+// Package fsx provides convenient abstractions to work with the filesystem.
 package fsx
 
-import "os"
+import (
+	"os"
+)
 
+// Exists checks if the given path exists
 func Exists(path string) bool {
 	_, err := os.Stat(path)
 	return err == nil
 }
 
+// IsDirectory checks if the provided path exists and is a directory
 func IsDirectory(path string) bool {
 	info, err := os.Stat(path)
 	return err == nil && info.Mode().IsDir()
 }
 
+// IsFile checks if the provided path exists and is a regular file
 func IsFile(path string) bool {
 	info, err := os.Stat(path)
 	return err == nil && info.Mode().IsRegular()

internal/stack/installable.go

@@ -12,7 +12,7 @@ import (
 )
 
 // Installable represents a Stack that can be automatically installed from a set of resources
-// See the Install() method.
+// See the [Install] method.
 type Installable struct {
 	Stack