hush: fix more obscure ${var%...} cases

function                                             old     new   delta
add_till_closing_paren                               313     359     +46
builtin_exit                                          48      47      -1

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

shell/hush.c

@@ -45,6 +45,8 @@
  *      follow IFS rules more precisely, including update semantics
  *      builtins mandated by standards we don't support:
  *          [un]alias, command, fc, getopts, newgrp, readonly, times
+ *      make complex ${var%...} constructs support optional
+ *      make here documents optional
  *
  * Bash compat TODO:
  *      redirection of stdout+stderr: &> and >&
@@ -5887,36 +5889,36 @@ static void add_till_backquote(o_string *dest, struct in_str *input)
  * echo $(echo 'TEST)' BEST)            TEST) BEST
  * echo $(echo \(\(TEST\) BEST)         ((TEST) BEST
  *
- * BUG: enter: echo $(( `printf '(\x28 1'` + `echo 2))` ))
- * on the command line, press Enter. You get > prompt which is impossible
- * to exit with ^C.
+ * Also adapted to eat ${var%...} constructs, since ... part
+ * can contain arbitrary constructs, just like $(cmd).
  */
 #define DOUBLE_CLOSE_CHAR_FLAG 0x80
 static void add_till_closing_paren(o_string *dest, struct in_str *input, char end_ch)
 {
-	int count = 0;
 	char dbl = end_ch & DOUBLE_CLOSE_CHAR_FLAG;
 	end_ch &= (DOUBLE_CLOSE_CHAR_FLAG-1);
 	while (1) {
 		int ch = i_getch(input);
 		if (ch == EOF) {
-			syntax_error_unterm_ch(')');
+			syntax_error_unterm_ch(end_ch);
 			/*xfunc_die(); - redundant */
 		}
-		if (ch == '(' || ch == '{')
-			count++;
-		if (ch == ')' || ch == '}') {
-			count--;
-			if (count < 0 && ch == end_ch) {
-				if (!dbl)
-					break;
-				if (i_peek(input) == ')') {
-					i_getch(input);
-					break;
-				}
+		if (ch == end_ch) {
+			if (!dbl)
+				break;
+			/* we look for closing )) of $((EXPR)) */
+			if (i_peek(input) == end_ch) {
+				i_getch(input); /* eat second ')' */
+				break;
 			}
 		}
 		o_addchr(dest, ch);
+		if (ch == '(' || ch == '{') {
+			ch = (ch == '(' ? ')' : '}');
+			add_till_closing_paren(dest, input, ch);
+			o_addchr(dest, ch);
+			continue;
+		}
 		if (ch == '\'') {
 			add_till_single_quote(dest, input);
 			o_addchr(dest, ch);
@@ -5927,6 +5929,11 @@ static void add_till_closing_paren(o_string *dest, struct in_str *input, char en
 			o_addchr(dest, ch);
 			continue;
 		}
+		if (ch == '`') {
+			add_till_backquote(dest, input);
+			o_addchr(dest, ch);
+			continue;
+		}
 		if (ch == '\\') {
 			/* \x. Copy verbatim. Important for  \(, \) */
 			ch = i_getch(input);

shell/hush_test/hush-arith/arith.right

@@ -43,21 +43,30 @@ Format: 'expected actual'
 4 4
 29 29
 5 5
+unary plus, minus
 -4 -4
 4 4
+conditional expressions
 1 1
 32 32
 32 32
 1 1
 1 1
 32 32
+check that parentheses in `cmd` are interpreted correctly
+3 3
+check that the unevaluated part of the ternary operator does not do evaluation or assignment
 20 20
 30 30
 20 20
 30 30
+check precedence of assignment vs. conditional operator
 hush: error in arithmetic
+check precedence of assignment vs. conditional operator
+associativity of assignment-operator operator
 6 6
 6,5,3 6,5,3
+octal, hex
 263 263
 255 255
 40 40

shell/hush_test/hush-arith/arith.tests

@@ -75,11 +75,11 @@ echo 4 $(( iv &= 4 ))
 echo 29 $(( iv += (jv + 9)))
 echo 5 $(( (iv + 4) % 7 ))
 
-# unary plus, minus
+echo unary plus, minus
 echo -4 $(( +4 - 8 ))
 echo 4 $(( -4 + 8 ))
 
-# conditional expressions
+echo conditional expressions
 echo 1 $(( 4<5 ? 1 : 32))
 echo 32 $(( 4>5 ? 1 : 32))
 echo 32 $(( 4>(2+3) ? 1 : 32))
@@ -87,8 +87,11 @@ echo 1 $(( 4<(2+3) ? 1 : 32))
 echo 1 $(( (2+2)<(2+3) ? 1 : 32))
 echo 32 $(( (2+2)>(2+3) ? 1 : 32))
 
-# check that the unevaluated part of the ternary operator does not do
-# evaluation or assignment
+echo 'check that parentheses in `cmd` are interpreted correctly'
+# \x28 is '('
+echo 3 $(( ( `printf '(\x28 1'` + `echo 2\)\)` ) ))
+
+echo check that the unevaluated part of the ternary operator does not do evaluation or assignment
 x=i+=2
 y=j+=2
 #ash# declare -i i=1 j=1
@@ -109,20 +112,20 @@ echo 20 $((1 ? 20 : (x+=2)))
 echo 30 $((0 ? (y+=2) : 30))
 #ash# echo $i,$y             # ash mishandles this
 
-# check precedence of assignment vs. conditional operator
+echo check precedence of assignment vs. conditional operator
 # should be an error
 #ash# declare -i x=2
       x=2
 #ashnote# bash reports error but continues, ash aborts - using subshell to 'emulate' bash:
 (  y=$((1 ? 20 : x+=2))  )
 
-# check precedence of assignment vs. conditional operator
+echo check precedence of assignment vs. conditional operator
 #ash# declare -i x=2
       x=2
 # ash says "line NNN: syntax error: 0 ? x+=2 : 20"
 #ash# echo 20 $((0 ? x+=2 : 20))
 
-# associativity of assignment-operator operator
+echo associativity of assignment-operator operator
 #ash# declare -i i=1 j=2 k=3
 i=1
 j=2
@@ -130,7 +133,7 @@ k=3
 echo 6 $((i += j += k))
 echo 6,5,3 $i,$j,$k
 
-# octal, hex
+echo octal, hex
 echo 263 $(( 0x100 | 007 ))
 echo 255 $(( 0xff ))
 #ash# echo 255 $(( 16#ff ))

shell/hush_test/hush-vars/var_posix1.right

@@ -37,4 +37,5 @@ ababcdcd_tail
 ababcdcd
 ab
 ab
+ab
 End

shell/hush_test/hush-vars/var_posix1.tests

@@ -47,5 +47,6 @@ echo ${var%\\*}
 
 a=ab}; echo ${a%\}};
 a=abc; c=c; echo ${a%${c}}
+a=ab{{c; echo ${a%`echo {{c`}
 
 echo End