hush: fix "set -e; false || x=1; echo OK"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

5 files changed, 43 insertions, 7 deletions

diff --git a/shell/ash_test/ash-misc/assignment5.right b/shell/ash_test/ash-misc/assignment5.right
new file mode 100644
index 000000000..a91554c09
--- /dev/null
+++ b/shell/ash_test/ash-misc/assignment5.right
@@ -0,0 +1,5 @@
+Zero1:0
+Zero2:0
+Zero3:0
+Zero4:0 x:1 y:1
+Three:3 x:1 y:1
diff --git a/shell/ash_test/ash-misc/assignment5.tests b/shell/ash_test/ash-misc/assignment5.tests
new file mode 100755
index 000000000..0b8104285
--- /dev/null
+++ b/shell/ash_test/ash-misc/assignment5.tests
@@ -0,0 +1,9 @@
+true;  a=1; echo Zero1:$?
+false; a=1; echo Zero2:$?
+false || a=1; echo Zero3:$?
+
+false || x=$? y=`echo $?`; echo Zero4:$? x:$x y:$y
+false || x=$? y=`echo $?; exit 3`; echo Three:$? x:$x y:$y
+
+#ash sets z=1 instead of z=3. disabled for now
+#false || x=$? y=`echo $?; exit 3` z=`echo $?`; echo x:$x y:$y z:$z
diff --git a/shell/hush.c b/shell/hush.c
index 184d720f5..b64993faa 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -894,8 +894,9 @@ struct globals {
 # define G_flag_return_in_progress 0
 #endif
         smallint exiting; /* used to prevent EXIT trap recursion */
-        /* These four support $?, $#, and $1 */
+        /* These support $?, $#, and $1 */
         smalluint last_exitcode;
+        smalluint expand_exitcode;
         smalluint last_bg_pid_exitcode;
 #if ENABLE_HUSH_SET
         /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */
@@ -6209,6 +6210,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                          * and $IFS-split */
                         debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
                         G.last_exitcode = process_command_subs(&subst_result, arg);
+                        G.expand_exitcode = G.last_exitcode;
                         debug_printf_subst("SUBST RES:%d '%s'\n", G.last_exitcode, subst_result.data);
                         val = subst_result.data;
                         goto store_val;
@@ -8245,9 +8247,11 @@ static NOINLINE int run_pipe(struct pipe *pi)
 #endif
 
                 if (argv[command->assignment_cnt] == NULL) {
-                        /* Assignments, but no command */
-                        /* Ensure redirects take effect (that is, create files).
-                         * Try "a=t >file" */
+                        /* Assignments, but no command.
+                         * Ensure redirects take effect (that is, create files).
+                         * Try "a=t >file"
+                         */
+                        G.expand_exitcode = 0;
 #if 0 /* A few cases in testsuite fail with this code. FIXME */
                         rcode = redirect_and_varexp_helper(&new_env, /*old_vars:*/ NULL, command, &squirrel, /*argv_expanded:*/ NULL);
                         /* Set shell variables */
@@ -8265,7 +8269,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
                          * if evaluating assignment value set $?, retain it.
                          * Try "false; q=`exit 2`; echo $?" - should print 2: */
                         if (rcode == 0)
-                                rcode = G.last_exitcode;
+                                rcode = G.expand_exitcode;
                         /* Exit, _skipping_ variable restoring code: */
                         goto clean_up_and_ret0;
 
@@ -8292,9 +8296,13 @@ static NOINLINE int run_pipe(struct pipe *pi)
                                 bb_putchar_stderr('\n');
                         /* Redirect error sets $? to 1. Otherwise,
                          * if evaluating assignment value set $?, retain it.
-                         * Try "false; q=`exit 2`; echo $?" - should print 2: */
+                         * Else, clear $?:
+                         *  false; q=`exit 2`; echo $? - should print 2
+                         *  false; x=1; echo $? - should print 0
+                         * Because of the 2nd case, we can't just use G.last_exitcode.
+                         */
                         if (rcode == 0)
-                                rcode = G.last_exitcode;
+                                rcode = G.expand_exitcode;
                         IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
                         debug_leave();
                         debug_printf_exec("run_pipe: return %d\n", rcode);
diff --git a/shell/hush_test/hush-misc/assignment5.right b/shell/hush_test/hush-misc/assignment5.right
new file mode 100644
index 000000000..a91554c09
--- /dev/null
+++ b/shell/hush_test/hush-misc/assignment5.right
@@ -0,0 +1,5 @@
+Zero1:0
+Zero2:0
+Zero3:0
+Zero4:0 x:1 y:1
+Three:3 x:1 y:1
diff --git a/shell/hush_test/hush-misc/assignment5.tests b/shell/hush_test/hush-misc/assignment5.tests
new file mode 100755
index 000000000..0b8104285
--- /dev/null
+++ b/shell/hush_test/hush-misc/assignment5.tests
@@ -0,0 +1,9 @@
+true;  a=1; echo Zero1:$?
+false; a=1; echo Zero2:$?
+false || a=1; echo Zero3:$?
+
+false || x=$? y=`echo $?`; echo Zero4:$? x:$x y:$y
+false || x=$? y=`echo $?; exit 3`; echo Three:$? x:$x y:$y
+
+#ash sets z=1 instead of z=3. disabled for now
+#false || x=$? y=`echo $?; exit 3` z=`echo $?`; echo x:$x y:$y z:$z