feat: print exceptions to stderr (ESPTOOL-731)

espefuse/__init__.py

@@ -20,6 +20,7 @@
 import espefuse.efuse.esp32s3beta2 as esp32s3beta2_efuse
 
 import esptool
+from esptool.loader import REDIRECT_ERRORS
 
 DefChip = namedtuple("DefChip", ["chip_name", "efuse_lib", "chip_class"])
 
@@ -294,7 +295,10 @@ def _main():
     try:
         main()
     except esptool.FatalError as e:
-        print("\nA fatal error occurred: %s" % e)
+        print(
+            "\nA fatal error occurred: %s" % e,
+            file=sys.stderr if REDIRECT_ERRORS else sys.stdout,
+        )
         sys.exit(2)
 
 

espsecure/__init__.py

@@ -23,6 +23,7 @@
 import ecdsa
 
 import esptool
+from esptool.loader import REDIRECT_ERRORS
 
 SIG_BLOCK_MAGIC = 0xE7
 
@@ -1810,15 +1811,19 @@ def _main():
     try:
         main()
     except esptool.FatalError as e:
-        print("\nA fatal error occurred: %s" % e)
+        print(
+            "\nA fatal error occurred: %s" % e,
+            file=sys.stderr if REDIRECT_ERRORS else sys.stdout,
+        )
         sys.exit(2)
     except ValueError as e:
         try:
             if [arg for arg in e.args if "Could not deserialize key data." in arg]:
                 print(
                     "Note: This error originates from the cryptography module. "
                     "It is likely not a problem with espsecure, "
-                    "please make sure you are using a compatible OpenSSL backend."
+                    "please make sure you are using a compatible OpenSSL backend.",
+                    file=sys.stderr if REDIRECT_ERRORS else sys.stdout,
                 )
         finally:
             raise

esptool/__init__.py

@@ -65,7 +65,12 @@
     write_mem,
 )
 from esptool.config import load_config_file
-from esptool.loader import DEFAULT_CONNECT_ATTEMPTS, ESPLoader, list_ports
+from esptool.loader import (
+    DEFAULT_CONNECT_ATTEMPTS,
+    ESPLoader,
+    REDIRECT_ERRORS,
+    list_ports,
+)
 from esptool.targets import CHIP_DEFS, CHIP_LIST, ESP32ROM
 from esptool.util import (
     FatalError,
@@ -1072,23 +1077,30 @@ def _main():
     try:
         main()
     except FatalError as e:
-        print(f"\nA fatal error occurred: {e}")
+        print(
+            f"\nA fatal error occurred: {e}",
+            file=sys.stderr if REDIRECT_ERRORS else sys.stdout,
+        )
         sys.exit(2)
     except serial.serialutil.SerialException as e:
-        print(f"\nA serial exception error occurred: {e}")
+        file = sys.stderr if REDIRECT_ERRORS else sys.stdout
+        print(f"\nA serial exception error occurred: {e}", file=file)
         print(
             "Note: This error originates from pySerial. "
             "It is likely not a problem with esptool, "
-            "but with the hardware connection or drivers."
+            "but with the hardware connection or drivers.",
+            file=file,
         )
         print(
             "For troubleshooting steps visit: "
-            "https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html"
+            "https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html",  # noqa: E501
+            file=file,
         )
         sys.exit(1)
     except StopIteration:
-        print(traceback.format_exc())
-        print("A fatal error occurred: The chip stopped responding.")
+        file = sys.stderr if REDIRECT_ERRORS else sys.stdout
+        print(traceback.format_exc(), file=file)
+        print("A fatal error occurred: The chip stopped responding.", file=file)
         sys.exit(2)
 
 

esptool/loader.py

@@ -96,6 +96,8 @@
 DEFAULT_CONNECT_ATTEMPTS = cfg.getint("connect_attempts", 7)
 # Number of times to try writing a data block
 WRITE_BLOCK_ATTEMPTS = cfg.getint("write_block_attempts", 3)
+# Redirect errors to stderr
+REDIRECT_ERRORS = cfg.getboolean("redirect_errors", False)
 
 STUBS_DIR = os.path.join(os.path.dirname(__file__), "targets", "stub_flasher")
 

flasher_stub/esptool_test_stub.py

@@ -32,5 +32,8 @@
     try:
         esptool.main()
     except esptool.FatalError as e:
-        print("\nA fatal error occurred: %s" % e)
+        print(
+            "\nA fatal error occurred: %s" % e,
+            file=sys.stderr if globals()["redirect_errors"] else sys.stdout,
+        )
         sys.exit(2)

flasher_stub/wrap_stub.py

@@ -13,8 +13,10 @@
 import os.path
 import sys
 
-sys.path.append("..")
 import esptool  # noqa: E402
+from esptool.loader import REDIRECT_ERRORS
+
+sys.path.append("..")
 
 THIS_DIR = os.path.dirname(__file__)
 BUILD_DIR = os.path.join(THIS_DIR, "build")
@@ -52,7 +54,7 @@ def wrap_stub(elf_file):
             stub.get("data_start", 0),
             stub["entry"],
         ),
-        file=sys.stderr,
+        file=sys.stderr if REDIRECT_ERRORS else sys.stdout,
     )
 
     return stub