Merge branch 'fix-switch-default-first'

RELEASES.rst

@@ -892,6 +892,9 @@ Planned
 * Fix Duktape.act() lineNumber bug, PC used for lineNumber was off-by-one
   which sometimes resulted in incorrect linenumbers (GH-143)
 
+* Fix incorrect switch-case matching when default clause is the first clause
+  in a switch statement (GH-155)
+
 * Add support for TI-Nspire (using Ndless, see GH-113)
 
 2.0.0 (XXXX-XX-XX)

ecmascript-testcases/test-bug-switch-default-first.js

@@ -0,0 +1,67 @@
+/*
+ *  Reported by Andreas Oman (andoma)
+ *
+ *  https://github.com/svaarala/duktape/issues/155
+ */
+
+/*===
+10
+11
+10
+10
+11
+11
+10
+11
+10
+===*/
+
+// In Duktape 1.1.x this incorrectly returns 10 when v == 1.
+function test1(v) {
+    switch(v) {
+    default:
+    case 0:
+        return 10;
+    case 1:
+        return 11;
+    }
+}
+
+// Swapping case 0 and default would fix it; returns 11.
+function test2(v) {
+    switch(v) {
+    case 0:
+        return 10;
+    default:
+    case 1:
+        return 11;
+    }
+}
+
+// Adding a dummy case also fixed it; returns 11.
+function test3(v) {
+    switch(v) {
+    case 99:
+    default:
+    case 0:
+        return 10;
+    case 1:
+        return 11;
+    }
+}
+
+try {
+    print(test1(0));
+    print(test1(1));
+    print(test1(2));
+
+    print(test2(0));
+    print(test2(1));
+    print(test2(2));
+
+    print(test3(0));
+    print(test3(1));
+    print(test3(2));
+} catch (e) {
+    print(e.stack || e);
+}

ecmascript-testcases/test-dev-switch-odd-even.js

@@ -0,0 +1,72 @@
+/*
+ *  Multiple case clauses map to same action.
+ */
+
+/*===
+-2 out-of-range even-or-out-of-range
+-1 out-of-range even-or-out-of-range
+0 even even-or-out-of-range
+1 odd odd
+2 even even-or-out-of-range
+3 odd odd
+4 even even-or-out-of-range
+5 odd odd
+6 even even-or-out-of-range
+7 odd odd
+8 even even-or-out-of-range
+9 odd odd
+10 out-of-range even-or-out-of-range
+11 out-of-range even-or-out-of-range
+12 out-of-range even-or-out-of-range
+===*/
+
+function classify1(v) {
+    switch (v) {
+    case 0:
+    case 2:
+    case 4:
+    case 6:
+    case 8:
+        return 'even';
+    case 1:
+    case 3:
+    case 5:
+    case 7:
+    case 9:
+        return 'odd';
+    default:
+        return 'out-of-range';
+    }
+}
+
+function classify2(v) {
+    switch (v) {
+    default:
+    case 0:
+    case 2:
+    case 4:
+    case 6:
+    case 8:
+        return 'even-or-out-of-range';
+    case 1:
+    case 3:
+    case 5:
+    case 7:
+    case 9:
+        return 'odd';
+    }
+}
+
+function test() {
+    var i;
+
+    for (i = -2; i <= 12; i++) {
+        print(i, classify1(i), classify2(i));
+    }
+}
+
+try {
+    test();
+} catch (e) {
+    print(e.stack || e);
+}

src/duk_js_compiler.c

@@ -5303,6 +5303,15 @@ DUK_LOCAL void duk__parse_switch_stmt(duk_compiler_ctx *comp_ctx, duk_ivalue *re
 			duk__advance(comp_ctx);
 			duk__advance_expect(comp_ctx, DUK_TOK_COLON);
 
+			/* Fix for https://github.com/svaarala/duktape/issues/155:
+			 * If 'default' is first clause (detected by pc_prevcase < 0)
+			 * we need to ensure we stay in the matching chain.
+			 */
+			if (pc_prevcase < 0) {
+				DUK_DD(DUK_DDPRINT("default clause is first, emit prevcase jump"));
+				pc_prevcase = duk__emit_jump_empty(comp_ctx);
+			}
+
 			/* default clause matches next statement list (if any) */
 			pc_default = -2;
 		} else {