external/cde
1
0
Fork 0
mirror of git://git.code.sf.net/p/cdesktopenv/code synced 2025-03-09 15:50:02 +00:00
Code Issues Releases Wiki Activity

Remove a buggy optimization for variables in subshells

Browse source 
This bug was originally reported by @lijog in att/ast#7 and has been
reported again in #15. KSH does not save the state of a variable if it
is in a newer scope. This is because of an optimization in sh_assignok
first introduced in ksh93t+ 2010-05-24. Here is the code change in that
version:

                return(np);
        /* don't bother to save if in newer scope */
-       if(!(rp=shp->st.real_fun)  || !(dp=rp->sdict))
-               dp = sp->var;
-       if(np->nvenv && !nv_isattr(np,NV_MINIMAL|NV_EXPORT) && shp->last_root)
-               dp = shp->last_root;
-       if((mp=nv_search((char*)np,dp,HASH_BUCKET))!=np)
-       {
-               if(mp || !np->nvfun || np->nvfun->subshell>=sh.subshell)
-                       return(np);
-       }
+       if(sp->var!=shp->var_tree && shp->last_root==shp->var_tree)
+               return(np);
        if((ap=nv_arrayptr(np)) && (mp=nv_opensub(np)))
        {

This change was originally made to replace a buggier optimization.
However, the current optimization causes variables set in subshells
to wrongly affect the environment outside of the subshell, as the
variable does not get set back to its original value. This patch
simply removes the buggy optimization to fix this problem.

src/cmd/ksh93/sh/subshell.c:
 - Remove a buggy optimization that caused variables set in subshells
   to affect the environment outside of the subshell.

src/cmd/ksh93/tests/subshell.sh:
 - Add a regression test for setting variables in subshells. This
   test has to be run from the disk after being created with a here
   document because it always returns the expected result when run
   directly in the regression test script.
This commit is contained in:
Johnothan King 2020-06-15 06:43:37 -07:00
parent ef1621c18f
commit 3d38270b32
3 changed files with 16 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

3
src/cmd/ksh93/sh/subshell.c
View file

@ -251,9 +251,6 @@ Namval_t *sh_assignok(register Namval_t *np,int add)
/* don't bother with this */
if(!sp->shpwd || np==SH_LEVELNOD || np==L_ARGNOD || np==SH_SUBSCRNOD || np==SH_NAMENOD)
return(np);
/* don't bother to save if in newer scope */
if(sp->var!=shp->var_tree && sp->var!=shp->var_base && shp->last_root==shp->var_tree)
return(np);
if((ap=nv_arrayptr(np)) && (mp=nv_opensub(np)))
{
shp->last_root = ap->table;