Don't turn off SH_PROFILE in subshells (re: 4e185ee, 73c6457)

Some of the behaviours changes effectuated by the SH_PROFILE flag
(on while executing profile scripts like .kshrc) *should* remain in
effect in subshells. These include:

* $0 does not change within ksh functions (sh/macro.c:2856)
* dot scripts are parsed with SH_FUNEVAL, i.e., line by line and
  not all at once (bltins/misc.c:325)
* background job commands for the jobs list should not be taken
  from the history file (sh/jobs.c:1165)
* syntax error messages do not add an extra line number indication
  (sh/lex.c:2118)

The two referenced commits potentially introduced incorrect
behaviour for the above. On the other hand, the behaviours that
*should* change in subshells, even with SH_PROFILE on, and thus
were fixed by the referenced commits, are these:

* a background job from a subshell should not print a job number
  (sh/xec.c:1560)
* 'return' outside of functions in a subshell should still act like
  'exit' (bltins/cflow.c:47)

So the latter two cases need to be fixed separately instead,
i.e., without turning off the SH_PROFILE flag.

src/cmd/ksh93/sh/subshell.c,
src/cmd/ksh93/sh/args.c:
- Revert changes from the referenced commits: do not turn off the
  SH_PROFILE flag in subshells, or before forking to execute a
  process substitution.

src/cmd/ksh93/include/shell.h,
src/cmd/ksh93/sh/args.c,
src/cmd/ksh93/sh/xec.c:
- Add SH_PROCSUB state flag.
- Set it in procsubst() before calling sh_exec() to run a process
  substitution. This is done before forking, so a sh.realsubshell
  check is not suitable for this; hence the state flag.
- In sh_exec(), do not print job number if sh_isstate(SH_PROCSUB).
  This reimplements the bugfix from the first referenced commit.

src/cmd/ksh93/bltins/cflow.c:
- When determining whether return should act like exit, do not
  honour SH_PROFILE if we're in a subshell (virtual or forked).

src/cmd/ksh93/bltins/cflow.c

@@ -44,7 +44,7 @@
 int	b_return(int n, char *argv[],Shbltin_t *context)
 {
 	/* 'return' outside of function, dotscript and profile behaves like 'exit' */
-	char do_exit = **argv=='e' || sh.fn_depth==0 && sh.dot_depth==0 && !sh_isstate(SH_PROFILE);
+	const int do_exit = **argv=='e' || sh.fn_depth==0 && sh.dot_depth==0 && (!sh_isstate(SH_PROFILE) || sh.realsubshell);
 	NOT_USED(context);
 	while((n = optget(argv, **argv=='e' ? sh_optexit : sh_optreturn))) switch(n)
 	{

src/cmd/ksh93/include/shell.h

@@ -83,6 +83,7 @@ typedef union Shnode_u Shnode_t;
 #define SH_XARG		21	/* set while in xarg (command -x) mode */
 #define SH_NOTILDEXP	22	/* set to disable tilde expansion */
 #define SH_EXEC		23	/* set while in exec(1) */
+#define SH_PROCSUB	24	/* set (also in parent shell) while executing process substitution */
 
 /*
  * Shell options (set -o). Used with sh_isoption(), sh_onoption(), sh_offoption().

src/cmd/ksh93/include/version.h

@@ -18,7 +18,7 @@
 
 #define SH_RELEASE_FORK	"93u+m"		/* only change if you develop a new ksh93 fork */
 #define SH_RELEASE_SVER	"1.1.0-alpha"	/* semantic version number: https://semver.org */
-#define SH_RELEASE_DATE	"2024-08-22"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2024-08-23"	/* must be in this format for $((.sh.version)) */
 #define SH_RELEASE_CPYR	"(c) 2020-2024 Contributors to ksh " SH_RELEASE_FORK
 
 /* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */

src/cmd/ksh93/sh/args.c

@@ -761,14 +761,14 @@ struct argnod *sh_argprocsub(struct argnod *argp)
 	/* turn off job control */
 	sh_offstate(SH_INTERACTIVE);
 	sh_offstate(SH_MONITOR);
-	sh_offstate(SH_PROFILE);
 	job.jobcontrol = 0;
 	/* run the process substitution */
 	sh.subshell = 0;
 	if(fd)
 		sh.inpipe = pv;
 	else
 		sh.outpipe = pv;
+	sh_onstate(SH_PROCSUB);
 	sh_exec((Shnode_t*)argp->argchn.ap,(int)sh_isstate(SH_ERREXIT));
 	/* restore the previous state */
 	sh.subshell = savesubshell;

src/cmd/ksh93/sh/jobs.c

@@ -1162,7 +1162,7 @@ int job_post(pid_t pid, pid_t join)
 		pw->p_pid,pw->p_pgrp,job.savesig,join);
 	sfsync(sfstderr);
 #endif /* DEBUG */
-	if(hp && !sh_isstate(SH_PROFILE))
+	if(hp && !sh_isstate(SH_PROFILE) && !sh.realsubshell)
 		pw->p_name=hist_tell(sh.hist_ptr,(int)hp->histind-1);
 	else
 		pw->p_name = -1;

src/cmd/ksh93/sh/subshell.c

@@ -650,7 +650,6 @@ Sfio_t *sh_subshell(Shnode_t *t, volatile int flags, int comsub)
 				else
 					sh_subfork();
 			}
-			sh_offstate(SH_PROFILE);
 			sh_exec(t,flags);
 		}
 	}

src/cmd/ksh93/sh/xec.c

@@ -1557,7 +1557,7 @@ int sh_exec(const Shnode_t *t, int flags)
 						sigrelease(SIGINT);
 				}
 				/* print job number */
-				if(type&FAMP && (sh_isstate(SH_PROFILE) || sh_isstate(SH_INTERACTIVE)))
+				if(type&FAMP && (sh_isstate(SH_INTERACTIVE) || sh_isstate(SH_PROFILE)) && !sh_isstate(SH_PROCSUB) && !sh.realsubshell)
 					sfprintf(sfstderr,"[%d]\t%d\n",jobid,parent);
 				break;
 			}

src/cmd/ksh93/tests/options.sh

@@ -531,10 +531,21 @@ do		if	{ date | true;} ; true
 done
 (( (SECONDS-t1) > .5 )) && err_exit 'pipefail should not wait for background processes'
 
-# process source files from profiles as profile files
-print '. ./dotfile' > envfile
-print $'alias print=:\nprint foobar' > dotfile
-[[ $(ENV=/.$PWD/envfile $SHELL -i -c : 2>/dev/null) == foobar ]] && err_exit 'files source from profile does not process aliases correctly'
+# ======
+print $'v=$(. ./dotfile)\n(. ./dotfile)\ncat <(. ./dotfile)\n. ./dotfile' > envfile
+# dot scripts sourced from profile files are parsed line by line, so that aliases take effect on the next line in the same file
+print $'alias print=:\nprint fail:subshell==${.sh.subshell} >&2' > dotfile
+got=$(ENV=/.$PWD/envfile "$SHELL" -i -c : 2>&1)
+exp=''
+[[ $got == "$exp" ]] || err_exit 'dot script sourced from profile does not process aliases correctly' \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+# $0 does not change in ksh functions within profile scripts
+print 'function BAD { echo $0; }; BAD >&2' > dotfile
+got=$(ENV=/.$PWD/envfile "$SHELL" -i -c : 2>&1)
+exp=$SHELL$'\n'$SHELL$'\n'$SHELL$'\n'$SHELL
+[[ $got == "$exp" ]] || err_exit '$0 in ksh function in profile script not correct' \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+
 
 # ======
 if [[ -o ?posix ]]; then