fix(tools): allow to save stdout and stderr if the exec command fails

Currently, if a command run by the exec command returns an error
code, its stdout and stderr are not saved. It could be beneficial to
store at least the stderr if requested. Additionally, avoid creating
output files when there is no content and also store the stderr
of the failed command to diag.log.

Signed-off-by: Frantisek Hrbata <[email protected]>

tools/idf_py_actions/diag_ext.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 import atexit
 import difflib
@@ -583,17 +583,18 @@ def cmd_exec(args: Dict, step: Dict, recipe: Dict) -> None:
 
     if p.returncode:
         warn(f'Exec command "{cmd}" failed with exit code {p.returncode}')
-        return
+        if p.stderr:
+            dbg(f'stderr: "{p.stderr}"')
 
-    if stdout:
+    if stdout and p.stdout:
         try:
             stdout_path.parent.mkdir(parents=True, exist_ok=True)
             with open(stdout_path, 'a' if append else 'w') as f:
                 f.write(p.stdout)
         except Exception:
             warn(f'Cannot write exec command "{cmd}" stdout to "{stdout}"')
 
-    if stderr:
+    if stderr and p.stderr:
         try:
             stderr_path.parent.mkdir(parents=True, exist_ok=True)
             with open(stderr_path, 'a' if append else 'w') as f: