7 files changed, 217 insertions, 3 deletions

diff --git a/shell/ash_test/ash-quoting/dollar_altvalue2.right b/shell/ash_test/ash-quoting/dollar_altvalue2.right
new file mode 100644
index 000000000..7cf37e379
--- /dev/null
+++ b/shell/ash_test/ash-quoting/dollar_altvalue2.right
@@ -0,0 +1,69 @@
+Unquoted '':
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+||
+end
+
+Unquoted "":
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+||
+end
+
+Quoted '':
+start:
+|''|
+end
+start:
+|'' |
+end
+start:
+| ''|
+end
+start:
+| '' |
+end
+start:
+|'' ''|
+end
+
+Quoted "":
+start:
+||
+end
+start:
+| |
+end
+start:
+| |
+end
+start:
+|  |
+end
+start:
+| |
+end
diff --git a/shell/ash_test/ash-quoting/dollar_altvalue2.tests b/shell/ash_test/ash-quoting/dollar_altvalue2.tests
new file mode 100755
index 000000000..3377eb27f
--- /dev/null
+++ b/shell/ash_test/ash-quoting/dollar_altvalue2.tests
@@ -0,0 +1,33 @@
+f() { echo start:; for i; do echo "|$i|"; done; echo end; }
+x=a
+
+echo "Unquoted '':"
+f ${x:+''}
+f ${x:+'' }
+f ${x:+ ''}
+f ${x:+ '' }
+f ${x:+'' ''}
+
+echo
+echo 'Unquoted "":'
+f ${x:+""}
+f ${x:+"" }
+f ${x:+ ""}
+f ${x:+ "" }
+f ${x:+"" ""}
+
+echo
+echo "Quoted '':"
+f "${x:+''}"
+f "${x:+'' }"
+f "${x:+ ''}"
+f "${x:+ '' }"
+f "${x:+'' ''}"
+
+echo
+echo 'Quoted "":'
+f "${x:+""}"
+f "${x:+"" }"
+f "${x:+ ""}"
+f "${x:+ "" }"
+f "${x:+"" ""}"
diff --git a/shell/ash_test/ash-quoting/dollar_altvalue9.right b/shell/ash_test/ash-quoting/dollar_altvalue9.right
index fc6c2697c..39342fe7c 100644
--- a/shell/ash_test/ash-quoting/dollar_altvalue9.right
+++ b/shell/ash_test/ash-quoting/dollar_altvalue9.right
@@ -3,6 +3,7 @@ Unquoted 1:
 |x y|
 |1|
 |2|
+||
 |1 2|
 |A|
 |B|
@@ -14,6 +15,7 @@ Unquoted 2:
 |ax y|
 |1|
 |2|
+||
 |1 2|
 |A|
 |B|
diff --git a/shell/hush.c b/shell/hush.c
index fc77b89fc..559595d2e 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -475,7 +475,6 @@
 #endif
 
 #define SPECIAL_VAR_SYMBOL_STR "\3"
-#define SPECIAL_VAR_SYMBOL_CHR '\3'
 #define SPECIAL_VAR_SYMBOL       3
 /* The "variable" with name "\1" emits string "\3". Testcase: "echo ^C" */
 #define SPECIAL_VAR_QUOTED_SVS   1
@@ -5950,6 +5949,8 @@ static int encode_then_append_var_plusminus(o_string *output, int n,
                                                 break;
                                         o_addqchr(&dest, ch);
                                 }
+                                o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+                                o_addchr(&dest, SPECIAL_VAR_SYMBOL);
                                 continue;
                         }
                 }
@@ -5959,6 +5960,10 @@ static int encode_then_append_var_plusminus(o_string *output, int n,
                 }
                 if (ch == '"') {
                         dest.o_expflags ^= EXP_FLAG_ESC_GLOB_CHARS;
+                        if (dest.o_expflags) {
+                                o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+                                o_addchr(&dest, SPECIAL_VAR_SYMBOL);
+                        }
                         continue;
                 }
                 if (ch == '\\') {
@@ -6565,7 +6570,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                 case SPECIAL_VAR_QUOTED_SVS:
                         /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_QUOTED_SVS><SPECIAL_VAR_SYMBOL> */
                         /* "^C variable", represents literal ^C char (possible in scripts) */
-                        o_addchr(output, SPECIAL_VAR_SYMBOL_CHR);
+                        o_addchr(output, SPECIAL_VAR_SYMBOL);
                         arg++;
                         break;
 #if ENABLE_HUSH_TICK
@@ -6627,7 +6632,8 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                 o_addstr(output, arg);
                 debug_print_list("expand_vars_to_list[b]", output, n);
         } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
-         && !(cant_be_null & 0x80) /* and all vars were not quoted. */
+         && !(cant_be_null & 0x80)   /* and all vars were not quoted */
+         && !output->has_quoted_part
         ) {
                 n--;
                 /* allow to reuse list[n] later without re-growth */
diff --git a/shell/hush_test/hush-quoting/dollar_altvalue2.right b/shell/hush_test/hush-quoting/dollar_altvalue2.right
new file mode 100644
index 000000000..7cf37e379
--- /dev/null
+++ b/shell/hush_test/hush-quoting/dollar_altvalue2.right
@@ -0,0 +1,69 @@
+Unquoted '':
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+||
+end
+
+Unquoted "":
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+end
+start:
+||
+||
+end
+
+Quoted '':
+start:
+|''|
+end
+start:
+|'' |
+end
+start:
+| ''|
+end
+start:
+| '' |
+end
+start:
+|'' ''|
+end
+
+Quoted "":
+start:
+||
+end
+start:
+| |
+end
+start:
+| |
+end
+start:
+|  |
+end
+start:
+| |
+end
diff --git a/shell/hush_test/hush-quoting/dollar_altvalue2.tests b/shell/hush_test/hush-quoting/dollar_altvalue2.tests
new file mode 100755
index 000000000..3377eb27f
--- /dev/null
+++ b/shell/hush_test/hush-quoting/dollar_altvalue2.tests
@@ -0,0 +1,33 @@
+f() { echo start:; for i; do echo "|$i|"; done; echo end; }
+x=a
+
+echo "Unquoted '':"
+f ${x:+''}
+f ${x:+'' }
+f ${x:+ ''}
+f ${x:+ '' }
+f ${x:+'' ''}
+
+echo
+echo 'Unquoted "":'
+f ${x:+""}
+f ${x:+"" }
+f ${x:+ ""}
+f ${x:+ "" }
+f ${x:+"" ""}
+
+echo
+echo "Quoted '':"
+f "${x:+''}"
+f "${x:+'' }"
+f "${x:+ ''}"
+f "${x:+ '' }"
+f "${x:+'' ''}"
+
+echo
+echo 'Quoted "":'
+f "${x:+""}"
+f "${x:+"" }"
+f "${x:+ ""}"
+f "${x:+ "" }"
+f "${x:+"" ""}"
diff --git a/shell/hush_test/hush-quoting/dollar_altvalue9.right b/shell/hush_test/hush-quoting/dollar_altvalue9.right
index fc6c2697c..39342fe7c 100644
--- a/shell/hush_test/hush-quoting/dollar_altvalue9.right
+++ b/shell/hush_test/hush-quoting/dollar_altvalue9.right
@@ -3,6 +3,7 @@ Unquoted 1:
 |x y|
 |1|
 |2|
+||
 |1 2|
 |A|
 |B|
@@ -14,6 +15,7 @@ Unquoted 2:
 |ax y|
 |1|
 |2|
+||
 |1 2|
 |A|
 |B|