[OE-core][PATCH] wic/engine: warn about old host debugfs for standalone directory copy

[Daniel Dragomir <daniel.dragomir@windriver.com>]

When wic is used in standalone mode, it relies on host tools such as
debugfs. For directory host->image copies into ext* partitions, wic
uses scripted debugfs "-f" input with multiple mkdir/write commands.

Older host debugfs versions (< 1.47) may behave unreliably in this
mode and can silently miss files. This does not affect builds using
debugfs from OE where the version is known to be sufficiently new.

Add a debugfs version check and emit a warning when an older host
debugfs is detected. The warning is shown once per run and does not
alter execution.

Signed-off-by: Daniel Dragomir <daniel.dragomir@windriver.com>
---
 scripts/lib/wic/engine.py | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/scripts/lib/wic/engine.py b/scripts/lib/wic/engine.py
index 565a0db38a..28a973f6c4 100644
--- a/scripts/lib/wic/engine.py
+++ b/scripts/lib/wic/engine.py
@@ -220,6 +220,42 @@ def wic_list(args, scripts_path):
 
     return False
 
+_DEBUGFS_VERSION = None
+_DEBUGFS_WARNED = False
+
+def debugfs_version_check(debugfs_path, min_ver=(1, 47, 0)):
+    global _DEBUGFS_VERSION, _DEBUGFS_WARNED
+
+    if _DEBUGFS_WARNED:
+        return
+
+    # Detect version once
+    if _DEBUGFS_VERSION is None:
+        out = ""
+        for flag in ("-V", "-v"):
+            try:
+                out = exec_cmd(f"{debugfs_path} {flag}")
+                break
+            except Exception:
+                continue
+
+        import re
+        m = re.search(r"(\d+)\.(\d+)\.(\d+)", out or "")
+        _DEBUGFS_VERSION = tuple(map(int, m.groups())) if m else None
+
+    ver = _DEBUGFS_VERSION
+
+    # Compare and warn once
+    if ver is not None and ver < min_ver:
+        logger.warning(
+            "debugfs %s detected (< 1.47): Directory copies into ext* partitions "
+            "via scripted debugfs (-f) may be unreliable. Consider using a newer "
+            "debugfs, for example via a native sysroot from a newer SDK.",
+            ".".join(map(str, ver)) if ver else "unknown"
+        )
+
+    _DEBUGFS_WARNED = True
+
 
 class Disk:
     def __init__(self, imagepath, native_sysroot, fstypes=('fat', 'ext')):
@@ -334,6 +370,7 @@ class Disk:
         if self.partitions[pnum].fstype.startswith('ext'):
             if isinstance(src, str): # host to image case
                 if os.path.isdir(src):
+                    debugfs_version_check(self.debugfs)
                     base = os.path.abspath(src)
                     base_parent = os.path.dirname(base)
                     cmds = []
-- 
2.25.1