Re: grep . /; echo $?

[Julian Foad]

Charles Levert wrote:

> The following changed the logic slightly,
> mostly so that read() errors on directories are
> always ignored (not just when the user asked
> for suppression), and that only the messages be
> suppressed for non-directories (but not the >1
> exit code).
>
> ] Working file: grep/src/grep.c
> ] ----------------------------
> ] revision 1.51
> ] date: 2001/02/08 16:12:10;  author: alainm;  state: Exp;  lines: +22 -12
> ] Exit status fix.
> ] ----------------------------
> ] No ChangeLog entry.

Huh.  That's a useful log message - not.  In fact, that change contains what I 
believe is the bug that caused directory read errors to be ignored, two further 
bugs, and an unrelated change.  Good grief!


+/* Like error, but suppress the diagnostic if requested.  */
+static void
+suppressible_error (char const *mesg, int errnum)
+{
+  if (! suppress_errors)
+    error (mesg, errnum);
+  errseen = 1;
+}

(One of the further bugs is that "errseen" is only set for suppressible errors: 
that line was moved out of the general "error" function.  This seems to have 
been subsequently fixed.)


-      if (! (is_EISDIR (errno, file) && suppress_errors))
-        error (filename, errno);
+      if (! is_EISDIR (errno, file))
+        suppressible_error (filename, errno);

The above change was made twice, and it causes directory errors to be always 
completely ignored, which I don't believe was the intent.

The other bug I see is in function grepfile().  After the change, if we're 
suppressing error messages, skipping a directory now sets "errseen".


> I didn't find anything around those dates on
> the mailing list (bug-gnu-utils, back then).

Thanks for doing this research.

It looks like we now have enough context to determine which aspects of the 
behaviour are bugs.

- Julian