tools: replace update-stubs.sh with a Go program

README.md

@@ -252,9 +252,9 @@ The library is organized in layers:
 
 The flasher includes pre-compiled bootloader stubs from [esp-flasher-stub](https://github.com/espressif/esp-flasher-stub) releases. To update stubs:
 
-1. Edit `STUB_VERSION` in `tools/update-stubs.sh` to the desired release version
+1. Edit `stubVersion` in `tools/update-stubs.go` to the desired release version
 2. Run `go generate ./pkg/espflasher/...` to download and embed the latest stubs
-3. The `go:generate` directive in `pkg/espflasher/stub.go` will invoke `tools/update-stubs.sh`
+3. The `go:generate` directive in `pkg/espflasher/stub.go` will invoke `tools/update-stubs.go`
 
 ## Protocol Reference
 

pkg/espflasher/stub.go

@@ -7,7 +7,7 @@ import (
 	"fmt"
 )
 
-//go:generate bash ../../tools/update-stubs.sh
+//go:generate go run ../../tools/update-stubs.go
 //go:embed stubs
 var stubFS embed.FS
 

tools/update-stubs.go

@@ -0,0 +1,71 @@
+// Command update-stubs downloads pre-compiled bootloader stubs from the
+// esp-flasher-stub GitHub releases and writes them to pkg/espflasher/stubs/.
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+)
+
+const (
+	stubVersion = "v0.5.1"
+	baseURL     = "https://github.com/espressif/esp-flasher-stub/releases/download/" + stubVersion
+)
+
+var chips = []string{
+	"esp8266",
+	"esp32",
+	"esp32s2",
+	"esp32s3",
+	"esp32c2",
+	"esp32c3",
+	"esp32c5",
+	"esp32c6",
+	"esp32h2",
+}
+
+func main() {
+	// Resolve the stubs directory relative to this tool's source file.
+	stubDir := filepath.Join("..", "pkg", "espflasher", "stubs")
+	if dir := os.Getenv("STUB_DIR"); dir != "" {
+		stubDir = dir
+	}
+
+	fmt.Printf("Downloading stubs from %s to %s\n", baseURL, stubDir)
+
+	for _, chip := range chips {
+		url := baseURL + "/" + chip + ".json"
+		dest := filepath.Join(stubDir, chip+".json")
+
+		if err := download(url, dest); err != nil {
+			fmt.Fprintf(os.Stderr, "error downloading %s: %v\n", chip, err)
+			os.Exit(1)
+		}
+	}
+
+	fmt.Printf("Successfully updated all %d stubs to %s\n", len(chips), stubVersion)
+}
+
+func download(url, dest string) error {
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("HTTP %s for %s", resp.Status, url)
+	}
+
+	f, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = io.Copy(f, resp.Body)
+	return err
+}