Careful when using chdir inside a dirEntries loop

[Jonathan M Davis]

On 2011-06-09 15:20, Andrej Mitrovic wrote:
> Here's a little buggy code which most often throws an exception:
> 
> foreach (string entry; dirEntries(curdir, SpanMode.shallow))
> {
> if (entry.isdir)
> {
> foreach (string subentry; dirEntries(entry, SpanMode.shallow))
> {
> if (subentry.isdir)
> {
> chdir(rel2abs(subentry));
> }
> }
> }
> }
> 
> Usually throws something like:
> std.file.FileException at std\file.d(1124): .\foo\bar.d: The system cannot
> find the path specified.
> 
> The problem is, chdir will modify curdir and dirEntries doesn't store
> 'curdir' internally as an absolute address.
> 
> The way to work around this is to call rel2abs as soon as possible when
> using 'curdir' (the first line changed):
> 
> foreach (string entry; dirEntries(rel2abs(curdir), SpanMode.shallow))
> {
> if (entry.isdir)
> {
> foreach (string subentry; dirEntries(entry, SpanMode.shallow))
> {
> if (subentry.isdir)
> {
> chdir(rel2abs(subentry));
> }
> }
> }
> }
> 
> I've had a use for code like this because where I was invoking a batch file
> which was always relative to the current subdirectory. But anyways, I just
> thought I'd throw it out in case anyone else runs into this.

I'm not sure if that's a valid bug or not. It could easily be a case of "just 
don't do that," or it could be that dirEntries needs to be improved. Open a 
bug report on it so that it's at least recorded and known. Then we can decide 
the best course of action to take with it.

- Jonathan M Davis