Re: Odd, is it not? mkdir 'e:\' cannot be undone by rmdir 'e:\' ...

[Ken Brown <kbrown@cornell.edu>]

On 9/20/2019 5:11 AM, Houder wrote:
> As I said already, the snippet should NOT be executed in general. Perhaps
> it is another left-over from old times that should have been deleted.

You're absolutely right.  Prior to commit b0717aae0, the code looked like this:

       if (strncmp (path, "\\\\.\\", 4))
	{
	  /* Windows ignores trailing dots and spaces in the last path
	     component, and ignores exactly one trailing dot in inner
	     path components. */
	  char *tail = NULL;
           [...]
	  if (!tail || tail == path)
	    /* nothing */;
	  else if (tail[-1] != '\\')
	    {
	      *tail = '\0';
	      strip_tail = true;
	    }
	  else
	    {
	      error = ENOENT;
	      return;
	    }
	}

Note the use of a *local* tail variable.  It's a pointer into path, as you can 
see by looking at the part I omitted.

In commit b0717aae0, Corinna intended to disable this code, but she 
inadvertently disabled only part of it.  Here's the relevant part of that commit:

@@ -1170,6 +1225,7 @@ out:
      {
        if (strncmp (path, "\\\\.\\", 4))
         {
+#if 0
           /* Windows ignores trailing dots and spaces in the last path
              component, and ignores exactly one trailing dot in inner
              path components. */
@@ -1190,7 +1246,7 @@ out:
                   tail = NULL;
                 }
             }
-
+#endif
           if (!tail || tail == path)
             /* nothing */;
           else if (tail[-1] != '\\')

In particular, the declaration of the local tail variable is in the disabled 
code, so the cruft at the end is referring to the other tail, which points into 
path_copy.

[A later commit removed the disabled code.]

I'll fix this and then look at your patches to mkdir and rmdir.  It would be 
very helpful if you would write these as a patch series with cover letter, using 
git format-patch, and send them to the cygwin-patches list.

Ken

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