Add optional 'onerror' argument to os.walk(), to control error
handling.
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index dd492bb..074d332 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -1054,7 +1054,8 @@
Availability: Macintosh, \UNIX, Windows.
\end{funcdesc}
-\begin{funcdesc}{walk}{top\optional{, topdown\code{=True}}}
+\begin{funcdesc}{walk}{top\optional{, topdown\code{=True}
+ \optional{, onerror\code{=None}}}}
\index{directory!walking}
\index{directory!traversal}
\function{walk()} generates the file names in a directory tree, by
@@ -1087,6 +1088,13 @@
false is ineffective, because in bottom-up mode the directories in
\var{dirnames} are generated before \var{dirnames} itself is generated.
+By default errors from the \code{os.listdir()} call are ignored. If
+optional argument \var{onerror} is specified, it should be a function;
+it will be called with one argument, an os.error instance. It can
+report the error to continue with the walk, or raise the exception
+to abort the walk. Note that the filename is available as the
+\code{filename} attribute of the exception object.
+
\begin{notice}
If you pass a relative pathname, don't change the current working
directory between resumptions of \function{walk()}. \function{walk()}
diff --git a/Lib/os.py b/Lib/os.py
index 69d1a44..e493ad0 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -203,7 +203,7 @@
__all__.extend(["makedirs", "removedirs", "renames"])
-def walk(top, topdown=True):
+def walk(top, topdown=True, onerror=None):
"""Directory tree generator.
For each directory in the directory tree rooted at top (including top
@@ -232,6 +232,13 @@
dirnames have already been generated by the time dirnames itself is
generated.
+ By default errors from the os.listdir() call are ignored. If
+ optional arg 'onerror' is specified, it should be a function; it
+ will be called with one argument, an os.error instance. It can
+ report the error to continue with the walk, or raise the exception
+ to abort the walk. Note that the filename is available as the
+ filename attribute of the exception object.
+
Caution: if you pass a relative pathname for top, don't change the
current working directory between resumptions of walk. walk never
changes the current directory, and assumes that the client doesn't
@@ -259,7 +266,9 @@
# Note that listdir and error are globals in this module due
# to earlier import-*.
names = listdir(top)
- except error:
+ except error, err:
+ if onerror is not None:
+ onerror(err)
return
dirs, nondirs = [], []
@@ -274,7 +283,7 @@
for name in dirs:
path = join(top, name)
if not islink(path):
- for x in walk(path, topdown):
+ for x in walk(path, topdown, onerror):
yield x
if not topdown:
yield top, dirs, nondirs
diff --git a/Misc/NEWS b/Misc/NEWS
index d8a95a2..26b543b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -38,6 +38,9 @@
Library
-------
+- Added optional 'onerror' argument to os.walk(), to control error
+ handling.
+
- inspect.is{method|data}descriptor was added, to allow pydoc display
__doc__ of data descriptors.