Re: [PATCH] Kill regexp.h

[Zack Weinberg <zackw at panix dot com>]

On 07/15/2015 09:12 AM, Carlos O'Donell wrote:
> On 07/14/2015 08:20 PM, Zack Weinberg wrote:
>>> At a high level your patch looks OK, it makes sense to deprecate
>>> these interfaces, but I think we should to do this in two stages.
>>> Add warnings and then remove.
>>
>> Hm. If we do that then I would feel obliged to fix the bugs in the
>> header in phase one. I'm not sure that's worth doing...
> 
> Worth is certainly in the eye of the beholder. How would you feel if
> you were a user of this interface?

So thinking about this a bit more, would you take this patch for 2.22?
All it does is add #warning directives and correct the RETURN .vs. ERROR
thing (leaving the memory-allocation issue reported in Debian).

---
	* regexp.h: Add unconditional #warning stating that this header
	will be removed soon.  Revise banner comment to match.
	(compile): Consistently use ERROR instead of RETURN to report
	errors (partial fix for bz#18681).
	* regexp.c: Don't include regexp.h.
---
 NEWS          |  6 ++++++
 misc/regexp.c |  8 ++++----
 misc/regexp.h | 30 +++++++++++++++++-------------
 3 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/NEWS b/NEWS
index f91edc7..d9cf4a7 100644
--- a/NEWS
+++ b/NEWS
@@ -71,6 +71,12 @@ Version 2.22
   compliance. The new implementation fixes the following long-standing
   issues: BZ#6544, BZ#11216, BZ#12836, BZ#13151, BZ#13152, and
BZ#14292. The
   old implementation is still present for use be by existing binaries.
+
+* The header <regexp.h> is deprecated, and will be removed in a future
+  release.  (It was removed from POSIX long ago, and it has bugs we cannot
+  easily fix.  See BZ#18681 for more details.)  We suspect that no one has
+  used this header in many years, but if you have code that does use it,
+  you will need to update it to use <regex.h> instead.
 
 Version 2.21

diff --git a/misc/regexp.c b/misc/regexp.c
index 3b83203..d389804 100644
--- a/misc/regexp.c
+++ b/misc/regexp.c
@@ -17,8 +17,10 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */

-#define __DO_NOT_DEFINE_COMPILE
-#include <regexp.h>
+/* We don't include regexp.h here because of the macros it requires, and
+   because it now contains an unconditional #warning. */
+
+#include <regex.h>

 /* Define the variables used for the interface.  */
 char *loc1;
@@ -32,7 +34,6 @@ char *locs;
    found in the buffer starting at EXPBUF.  `loc1' will return the
    first character matched and `loc2' points to the next unmatched
    character.  */
-extern int __step (const char *string, const char *expbuf);
 int
 __step (const char *string, const char *expbuf)
 {
@@ -55,7 +56,6 @@ weak_alias (__step, step)
 /* Match the beginning of STRING with the compiled regular expression
    in EXPBUF.  If the match is successful `loc2' will contain the
    position of the first unmatched character.  */
-extern int __advance (const char *string, const char *expbuf);
 int
 __advance (const char *string, const char *expbuf)
 {
diff --git a/misc/regexp.h b/misc/regexp.h
index 3fc0bc5..f8eefe4 100644
--- a/misc/regexp.h
+++ b/misc/regexp.h
@@ -19,14 +19,18 @@
 #ifndef _REGEXP_H
 #define _REGEXP_H	1

-/* The contents of this header file was first standardized in X/Open
+/* The contents of this header file were first standardized in X/Open
    System Interface and Headers Issue 2, originally coming from SysV.
-   In issue 4, version 2, it is marked as TO BE WITDRAWN, and it has
-   been withdrawn in SUSv3.
+   In issue 4, version 2, it was marked as TO BE WITHDRAWN, and it was
+   duly withdrawn in issue 6.

-   This code shouldn't be used in any newly written code.  It is
-   included only for compatibility reasons.  Use the POSIX definition
-   in <regex.h> for portable applications and a reasonable interface.  */
+   This header is provided only for backward compatibility, and it will
+   be removed in the next release of GNU libc.  New code should use
+   <regex.h> instead.  */
+
+#warning "regexp.h is obsolete and buggy."
+#warning "It will be removed in the next release of GNU libc."
+#warning "Please update your code to use regex.h instead (no trailing
'p')."

 #include <features.h>
 #include <alloca.h>
@@ -182,19 +186,19 @@ compile (char *__restrict instring, char
*__restrict expbuf,
       case REG_ERPAREN:
       default:
 	/* There is no matching error code.  */
-	RETURN (36);
+	ERROR (36);
       case REG_ESUBREG:
-	RETURN (25);
+	ERROR (25);
       case REG_EBRACK:
-	RETURN (49);
+	ERROR (49);
       case REG_EPAREN:
-	RETURN (42);
+	ERROR (42);
       case REG_EBRACE:
-	RETURN (44);
+	ERROR (44);
       case REG_BADBR:
-	RETURN (46);
+	ERROR (46);
       case REG_ERANGE:
-	RETURN (11);
+	ERROR (11);
       case REG_ESPACE:
       case REG_ESIZE:
 	ERROR (50);
-- 
2.1.4

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