Zsh Mailing List Archive
Messages sorted by: Reverse Date, Date, Thread, Author

PATCH: local exports

It seems to be agreed that not having local parameters exportable is a
bug.  This is an attempt to fix it.  It works, so far as I've tried, for
both normal and special parameters (with or without the -h option).  The
exported value should now be consistent (modulo any other problems with
exporting variables irrespective of their being local or not) with the
in-shell value, which seems to me the only sensible way of doing this.

I'm sure this needs more testing.  I removed some special cases that
prevented exports of locals in various places in the code, but it's
possible there are some others hanging around.

I made `typeset +g -x' respect the explicit `+g', and I allowed `local' to
take `-x' without forcing on `-g' --- I take it this is uncontroversial.
This was necessary to get around the -g-with--x kludge.  Ksh 88 doesn't
have that and its `typeset -x' behaves more or less like `typeset +g -x'.
However, apparently ksh 88 leaves the global value in the environment
together with the local; zsh now deletes it, which seems to correspond to
the user's intention at the expense of a fairly minor inefficiency.

I hope there's nothing to excite controversy in this patch.


On the other matter of handling the combination of localness and
exportedness: I haven't touched this, since I'd probably get it wrong.
Having confused myself over this, I've come to these conclusions:

1 - We don't actually need the -g-kludge for typeset -x any more; it
doesn't correspond to ksh 88 (see above), wasn't present or documented in
zsh until one of the current development series, and isn't consistent with
the behaviour of the remaining flags.

2 - `export' in any case behaves like it does in ksh, though in zsh's case
that means the effect of `typeset -xg', as currently documented.  The zsh
behaviour was always as now, I believe.  The ksh 88 behaviour makes
`export' and `typeset -x' behave differently, too, but it's undocumented.

3 - In fact, none of this interaction between exportedness and globalness
seems to be documented in the ksh 88 manual page.

4 - Therefore it's hard to see the use of an option or different emulation
settings, but it's possible I've missed some other issue.  We're agreed the
old behaviour was broken, so we don't want to emulate that.  If an option
for ksh compatibility is required, the base zsh behaviour should be as
clean as possible, i.e. no unexpected combinations (even if documented).

4 - Consequently I think we can remove the -g => -xg kludge in either case.
But I didn't quite follow why it was there.  If it was simply a workaround
for the -x being ignored otherwise, then maybe we can simply get rid of it
and put an end to the matter.


Index: Doc/Zsh/builtins.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/builtins.yo,v
retrieving revision 1.2
diff -u -r1.2 builtins.yo
--- Doc/Zsh/builtins.yo	2000/04/01 20:43:44	1.2
+++ Doc/Zsh/builtins.yo	2000/04/13 13:26:28
@@ -595,9 +595,10 @@
 endsitem()
 )
 findex(local)
-item(tt(local) [ {tt(PLUS())|tt(-)}tt(AEFLRUZahilrtu) [var(n)]] [ var(name)[tt(=)var(value)] ] ...)(
-Same as tt(typeset), except that the options tt(-g), tt(-x) and
-tt(-f) are not permitted.
+item(tt(local) [ {tt(PLUS())|tt(-)}tt(AEFLRUZahilrtux) [var(n)]] [ var(name)[tt(=)var(value)] ] ...)(
+Same as tt(typeset), except that the options tt(-g), and
+tt(-f) are not permitted.  In this case the tt(-x) option does not force
+the use of tt(-g), i.e. exported variables will be local to functions.
 )
 findex(log)
 vindex(watch, use of)
@@ -1003,9 +1004,7 @@
 function completes.  See
 ifzman(`Local Parameters' in zmanref(zshparam))\
 ifnzman(noderef(Local Parameters))\
-.  Local parameters are not exported unless tt(ALL_EXPORT) is set, in
-which case the parameter is exported em(only) when var(name) does not
-already exist.  The same rules apply to special shell parameters, which
+.  The same rules apply to special shell parameters, which
 retain their special attributes when made local.
 
 For each var(name)tt(=)var(value) assignment, the parameter
@@ -1161,7 +1160,9 @@
 )
 item(tt(-x))(
 Mark for automatic export to the environment of subsequently
-executed commands.
+executed commands.  Currently this implies the option tt(-g), unless tt(+g)
+is also explicitly given, in other words the parameter is not made local to
+the enclosing function.  This is for compatibility with other shells.
 )
 enditem()
 )
Index: Doc/Zsh/params.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/params.yo,v
retrieving revision 1.2
diff -u -r1.2 params.yo
--- Doc/Zsh/params.yo	2000/04/01 20:43:44	1.2
+++ Doc/Zsh/params.yo	2000/04/13 13:26:28
@@ -215,21 +215,19 @@
 
 Special parameters may also be made local; they retain their special
 attributes unless either the existing or the newly-created parameter
-has the tt(-h) (hide) attribute.  This may have unexpected effects.
-Firstly, there is no default value, so if there is no assigment at the
+has the tt(-h) (hide) attribute.  This may have unexpected effects:
+there is no default value, so if there is no assigment at the
 point the variable is made local, it will be set to an empty value (or zero
-in the case of integers).  Secondly, special parameters which are made
-local will not be exported (as with other parameters), so that the global
-value of the parameter remains present in the environment if it is already
-there.  This should be particularly noted in the case of tt(PATH): the
-shell will use the local version of tt(PATH) for finding programmes, but
-programmes using the shell's environment will inherit the global version.
+in the case of integers).  
 The following:
 
 example(typeset PATH=/new/directory:$PATH)
 
-is valid for temporarily allowing the shell to find the programs in
-tt(/new/directory) inside a function.
+is valid for temporarily allowing the shell or programmes called from it to
+find the programs in tt(/new/directory) inside a function.
+
+Note that the restriction in older versions of zsh that local parameters
+were never exported has been removed.
 
 texinode(Parameters Set By The Shell)(Parameters Used By The Shell)(Local Parameters)(Parameters)
 sect(Parameters Set By The Shell)
Index: Src/builtin.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/builtin.c,v
retrieving revision 1.6
diff -u -r1.6 builtin.c
--- Src/builtin.c	2000/04/13 08:43:39	1.6
+++ Src/builtin.c	2000/04/13 13:26:29
@@ -79,7 +79,7 @@
     BUILTIN("jobs", 0, bin_fg, 0, -1, BIN_JOBS, "dlpZrs", NULL),
     BUILTIN("kill", 0, bin_kill, 0, -1, 0, NULL, NULL),
     BUILTIN("let", 0, bin_let, 1, -1, 0, NULL, NULL),
-    BUILTIN("local", BINF_TYPEOPTS | BINF_MAGICEQUALS | BINF_PSPECIAL, bin_typeset, 0, -1, 0, "AEFLRTUZahilrtu", NULL),
+    BUILTIN("local", BINF_TYPEOPTS | BINF_MAGICEQUALS | BINF_PSPECIAL, bin_typeset, 0, -1, 0, "AEFLRTUZahilrtux", NULL),
     BUILTIN("log", 0, bin_log, 0, 0, 0, NULL, NULL),
     BUILTIN("logout", 0, bin_break, 0, 1, BIN_LOGOUT, NULL, NULL),
 
@@ -644,14 +644,12 @@
     setsparam("OLDPWD", ztrdup(oldpwd));
 
     pm = (Param) paramtab->getnode(paramtab, "PWD");
-    if (!(pm->flags & PM_EXPORTED) &&
-	(!pm->level || (isset(ALLEXPORT) && !pm->old))) {
+    if (!(pm->flags & PM_EXPORTED)) {
 	pm->flags |= PM_EXPORTED;
 	pm->env = addenv("PWD", pwd, pm->flags);
     }
     pm = (Param) paramtab->getnode(paramtab, "OLDPWD");
-    if (!(pm->flags & PM_EXPORTED) &&
-	(!pm->level || (isset(ALLEXPORT) && !pm->old))) {
+    if (!(pm->flags & PM_EXPORTED)) {
 	pm->flags |= PM_EXPORTED;
 	pm->env = addenv("OLDPWD", oldpwd, pm->flags);
     }
@@ -1589,7 +1587,6 @@
     }
 
     /*
-     * According to the manual, local parameters don't get exported.
      * A parameter will be local if
      * 1. we are re-using an existing local parameter
      *    or
@@ -1598,10 +1595,6 @@
      *     or
      *   ii. we are creating a new local parameter
      */
-    if ((usepm && pm->level) ||
-	(!usepm && (pm || (locallevel && (on & PM_LOCAL)))))
-	on &= ~PM_EXPORTED;
-
     if (usepm) {
 	on &= ~PM_LOCAL;
 	if (!on && !roff && !value) {
@@ -1630,9 +1623,7 @@
 	    if (pm->flags & PM_EXPORTED) {
 		if (!(pm->flags & PM_UNSET) && !pm->env && !value)
 		    pm->env = addenv(pname, getsparam(pname), pm->flags);
-	    } else if (pm->env &&
-		       (!pm->level || (isset(ALLEXPORT) && !pm->old &&
-				       !(pm->flags & PM_HASHELEM)))) {
+	    } else if (pm->env && !(pm->flags & PM_HASHELEM)) {
 		delenv(pm->env);
 		zsfree(pm->env);
 		pm->env = NULL;
@@ -1708,7 +1699,11 @@
 	tpm->old = pm->old;
 	tpm->level = pm->level;
 	tpm->ct = pm->ct;
-	tpm->env = pm->env;
+	if (pm->env) {
+	    delenv(pm->env);
+	    zsfree(pm->env);
+	}
+	tpm->env = pm->env = NULL;
 
 	pm->old = tpm;
 	/*
@@ -1725,7 +1720,6 @@
 	    pm->ct = auxlen;
 	else
 	    pm->ct = 0;
-	pm->env = NULL;
     } else {
 	/*
 	 * Create a new node for a parameter with the flags in `on' minus the
@@ -1856,7 +1850,7 @@
 	return 0;
     }
 
-    if (!ops['g'] && !ops['x'])
+    if ((!ops['g'] && !ops['x']) || ops['g'] == 2 || *name == 'l')
 	on |= PM_LOCAL;
 
     if (on & PM_TIED) {
Index: Src/params.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/params.c,v
retrieving revision 1.3
diff -u -r1.3 params.c
--- Src/params.c	2000/04/04 12:02:04	1.3
+++ Src/params.c	2000/04/13 13:26:29
@@ -643,13 +643,21 @@
 	} else {
 	    pm = (Param) zcalloc(sizeof *pm);
 	    if ((pm->old = oldpm)) {
-		/* needed to avoid freeing oldpm */
+		/*
+		 * needed to avoid freeing oldpm, but we do take it
+		 * out of the environment when it's hidden.
+		 */
+		if (oldpm->env) {
+		    delenv(oldpm->env);
+		    zsfree(oldpm->env);
+		    oldpm->env = NULL;
+		}
 		paramtab->removenode(paramtab, name);
 	    }
 	    paramtab->addnode(paramtab, ztrdup(name), pm);
 	}
 
-	if (isset(ALLEXPORT) && !oldpm && !(flags & PM_HASHELEM))
+	if (isset(ALLEXPORT) && !(flags & PM_HASHELEM))
 	    flags |= PM_EXPORTED;
     } else {
 	pm = (Param) zhalloc(sizeof *pm);
@@ -1446,11 +1454,30 @@
 }
 
 /**/
+void
+export_param(Param pm)
+{
+    char buf[(sizeof(zlong) * 8) + 4], *val;
+
+    if (PM_TYPE(pm->flags) == PM_INTEGER)
+	convbase(val = buf, pm->gets.ifn(pm), pm->ct);
+    else if (pm->flags & (PM_EFLOAT|PM_FFLOAT))
+	val = convfloat(pm->gets.ffn(pm), pm->ct,
+			pm->flags, NULL);
+    else
+	val = pm->gets.cfn(pm);
+    if (pm->env)
+	pm->env = replenv(pm->env, val, pm->flags);
+    else {
+	pm->flags |= PM_EXPORTED;
+	pm->env = addenv(pm->nam, val, pm->flags);
+    }
+}
+
+/**/
 mod_export void
 setstrvalue(Value v, char *val)
 {
-    char buf[(sizeof(zlong) * 8) + 4];
-
     if (v->pm->flags & PM_READONLY) {
 	zerr("read-only variable: %s", v->pm->nam, 0);
 	zsfree(val);
@@ -1523,22 +1550,10 @@
 	break;
     }
     if ((!v->pm->env && !(v->pm->flags & PM_EXPORTED) &&
-	 !(isset(ALLEXPORT) && !v->pm->old && !(v->pm->flags & PM_HASHELEM))) ||
+	 !(isset(ALLEXPORT) && !(v->pm->flags & PM_HASHELEM))) ||
 	(v->pm->flags & PM_ARRAY) || v->pm->ename)
 	return;
-    if (PM_TYPE(v->pm->flags) == PM_INTEGER)
-	convbase(val = buf, v->pm->gets.ifn(v->pm), v->pm->ct);
-    else if (v->pm->flags & (PM_EFLOAT|PM_FFLOAT))
-	val = convfloat(v->pm->gets.ffn(v->pm), v->pm->ct,
-			v->pm->flags, NULL);
-    else
-	val = v->pm->gets.cfn(v->pm);
-    if (v->pm->env)
-	v->pm->env = replenv(v->pm->env, val, v->pm->flags);
-    else {
-	v->pm->flags |= PM_EXPORTED;
-	v->pm->env = addenv(v->pm->nam, val, v->pm->flags);
-    }
+    export_param(v->pm);
 }
 
 /**/
@@ -1969,6 +1984,15 @@
 	if ((PM_TYPE(oldpm->flags) == PM_SCALAR) &&
 	    oldpm->sets.cfn == strsetfn)
 	    adduserdir(oldpm->nam, oldpm->u.str, 0, 0);
+	if (oldpm->flags & PM_EXPORTED) {
+	    /*
+	     * Re-export the old value which we removed in typeset_single().
+	     * I don't think we need to test for ALL_EXPORT here, since if
+	     * it was used to export the parameter originally the parmeter
+	     * should still have the PM_EXPORTED flag.
+	     */
+	    export_param(oldpm);
+	}
     }
 
     paramtab->freenode((HashNode) pm); /* free parameter node */
@@ -2745,7 +2769,7 @@
      */
     if (t == path)
 	cmdnamtab->emptytable(cmdnamtab);
-    if ((pm->flags & PM_HASHELEM) || (isset(ALLEXPORT) ? !!pm->old : pm->level))
+    if (pm->flags & PM_HASHELEM)
 	return;
     u = t ? zjoin(t, ':', 1) : "";
     len_s = strlen(s);
@@ -3013,7 +3037,11 @@
 	    pm->flags = (tpm->flags & ~PM_NORESTORE);
 	    pm->level = tpm->level;
 	    pm->ct = tpm->ct;
-	    pm->env = tpm->env;
+	    if (pm->env) {
+		delenv(pm->env);
+		zsfree(pm->env);
+	    }
+	    pm->env = NULL;
 
 	    if (!(tpm->flags & PM_NORESTORE))
 		switch (PM_TYPE(pm->flags)) {
@@ -3035,6 +3063,9 @@
 		    break;
 		}
 	    zfree(tpm, sizeof(*tpm));
+
+	    if (pm->flags & PM_EXPORTED)
+		export_param(pm);
 	} else
 	    unsetparam_pm(pm, 0, 0);
     }

-- 
Peter Stephenson <pws@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cambridge Silicon Radio, Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070
Messages sorted by: Reverse Date, Date, Thread, Author