Merge pull request #17 from AlessioGiacobbe/fix/multilevel-break-propagation

fix(parser): propagate multi-level break/continue before trailing statements of enclosing bodies

src/CompilerBase.php

@@ -1687,6 +1687,8 @@ class CompilerBase implements PropertyAccessContext
         $lines     = [];
         $inLoopTop = $this->context->inLoop;
         $inContinuableLoopTop = $this->context->inContinuableLoop;
+        $breakableIsSwitchTop = $this->context->breakableIsSwitch;
+        $breakableDepthTop = $this->context->breakableDepth;
         $last = array_key_last($stmts);
         foreach ($stmts as $i => $v) {
             $class                 = $v->getType();
@@ -1718,37 +1720,37 @@ class CompilerBase implements PropertyAccessContext
                     $result = $this->parseReturn($v);
                     break;
                 case 'Stmt_For':
-                    $this->context->inLoop = true;
-                    $this->context->inContinuableLoop = true;
-                    $result       = $this->parseFor($v);
-                    $this->context->inLoop = $inLoopTop;
-                    $this->context->inContinuableLoop = $inContinuableLoopTop;
-                    break;
                 case 'Stmt_Foreach':
-                    $this->context->inLoop = true;
-                    $this->context->inContinuableLoop = true;
-                    $result       = $this->parseForeach($v);
-                    $this->context->inLoop = $inLoopTop;
-                    $this->context->inContinuableLoop = $inContinuableLoopTop;
-                    break;
                 case 'Stmt_Switch':
-                    $this->context->inLoop = true;
-                    $result       = $this->parseSwitch($v);
-                    $this->context->inLoop = $inLoopTop;
-                    break;
                 case 'Stmt_While':
-                    $this->context->inLoop = true;
-                    $this->context->inContinuableLoop = true;
-                    $result       = $this->parseWhile($v);
-                    $this->context->inLoop = $inLoopTop;
-                    $this->context->inContinuableLoop = $inContinuableLoopTop;
-                    break;
                 case 'Stmt_Do':
+                    $isSwitch = $class === 'Stmt_Switch';
                     $this->context->inLoop = true;
-                    $this->context->inContinuableLoop = true;
+                    if (!$isSwitch) {
-                    $result       = $this->parseDo($v);
+                        $this->context->inContinuableLoop = true;
+                    }
+                    $this->context->breakableIsSwitch = $isSwitch;
+                    $this->context->breakableDepth = $breakableDepthTop + 1;
+                    $result = match ($class) {
+                        'Stmt_For' => $this->parseFor($v),
+                        'Stmt_Foreach' => $this->parseForeach($v),
+                        'Stmt_Switch' => $this->parseSwitch($v),
+                        'Stmt_While' => $this->parseWhile($v),
+                        default => $this->parseDo($v),
+                    };
                     $this->context->inLoop = $inLoopTop;
                     $this->context->inContinuableLoop = $inContinuableLoopTop;
+                    $this->context->breakableIsSwitch = $breakableIsSwitchTop;
+                    $this->context->breakableDepth = $breakableDepthTop;
+                    // A multi-level break/continue exits the nested construct
+                    // with its countdown flag still set. The propagation check
+                    // must run before any trailing statement of this body.
+                    if ($inLoopTop) {
+                        $flagCheck = $this->genMultiLevelJumpCheck($breakableIsSwitchTop);
+                        if ($flagCheck !== '') {
+                            $result = rtrim($result, "\r\n") . PHP_EOL . $flagCheck;
+                        }
+                    }
                     break;
                 case 'Stmt_If':
                     $result = $this->parseIf($v);

src/Context/FunctionContext.php

@@ -84,6 +84,10 @@ class FunctionContext
     public bool $inLoop = false;
     /** True while parsing a for/foreach/while/do-while body. */
     public bool $inContinuableLoop = false;
+    /** Number of breakable constructs (loops and switches) enclosing the statement being parsed. */
+    public int $breakableDepth = 0;
+    /** True when the innermost enclosing breakable construct is a switch, not a loop. */
+    public bool $breakableIsSwitch = false;
     public bool $inClosure = false;
     public ?array $closureReturnTypeCheck = null;
     public string $closureReturnTypeStr = '';

src/Parser/ForeachTrait.php

@@ -48,7 +48,7 @@ trait ForeachTrait
 
     protected function parseForeachBody(Foreach_ $node): string
     {
-        return $this->parseStmts($node->stmts) . $this->genLoopEndFlagCheck();
+        return $this->parseStmts($node->stmts);
     }
 
     protected function parseForeachKeyAssignment(Foreach_ $node, string $keyExpr, string $defaultType = Type::VAR): string

src/Parser/LoopControlTrait.php

@@ -102,7 +102,6 @@ trait LoopControlTrait
         $code .= ') {' . PHP_EOL;
 
         $code .= $this->parseBlockStmts($stmts);
-        $code .= $this->genLoopEndFlagCheck();
         $code .= $this->getIndent() . '}' . PHP_EOL;
 
         return $code;
@@ -138,7 +137,6 @@ trait LoopControlTrait
             $code .= 'while (' . $cond . ') {' . PHP_EOL;
         }
         $code .= $this->parseBlockStmts($stmts);
-        $code .= $this->genLoopEndFlagCheck();
         $code .= $this->getIndent() . '}' . PHP_EOL;
 
         return $code;
@@ -172,7 +170,6 @@ trait LoopControlTrait
         $code  = $this->parseBeforeStmtLines() . PHP_EOL;
         $code .= 'do {' . PHP_EOL;
         $code .= $bodyCode;
-        $code .= $this->genLoopEndFlagCheck();
         $code .= $this->getIndent() . '} while (' . $cond . ');' . PHP_EOL;
 
         return $code;
@@ -189,6 +186,7 @@ trait LoopControlTrait
         }
         $num = $v->num;
         if ($num) {
+            $this->checkLoopJumpLevel($v, $num, 'break');
             if ($num->value > 1) {
                 $this->context->hasMultiLevelBreak = true;
                 return '_brk_flag = ' . ($num->value - 1) . '; break;';
@@ -205,6 +203,7 @@ trait LoopControlTrait
         }
         $num = $v->num;
         if ($num) {
+            $this->checkLoopJumpLevel($v, $num, 'continue');
             if ($num->value > 1) {
                 $this->context->hasMultiLevelContinue = true;
                 return '_cnt_flag = ' . ($num->value - 1) . '; break;';
@@ -214,12 +213,32 @@ trait LoopControlTrait
     }
 
     /**
-     * Emit flag-propagation checks at the end of a loop body.
+     * PHP only accepts a positive integer literal that does not exceed the
+     * number of enclosing loops/switches. The flag lowering relies on this:
+     * it guarantees the countdown reaches zero at an enclosing construct.
+     */
+    protected function checkLoopJumpLevel(Node\Stmt $v, Node\Expr $num, string $operator): void
+    {
+        if (!$num instanceof Node\Scalar\Int_ || $num->value < 1) {
+            $this->fatalError($v, "'{$operator}' operator accepts only positive integer literals");
+        }
+        if ($num->value > $this->context->breakableDepth) {
+            $this->fatalError($v, "Cannot '{$operator}' {$num->value} levels");
+        }
+    }
+
+    /**
+     * Emit flag-propagation checks right after a nested breakable construct.
      *
-     * Translates multi-level break / continue into plain break / continue
+     * A multi-level break / continue is lowered to a flag assignment plus a
-     * by decrementing a counter at each loop boundary until it reaches zero.
+     * plain break out of the innermost construct. Each enclosing loop or
+     * switch places this check immediately after every nested loop / switch
+     * statement, so the flag keeps breaking outward — before any trailing
+     * statements of the enclosing body can run — until it reaches zero at
+     * the targeted level. When the check sits inside a switch, a continue
+     * that lands on the switch level behaves like break, matching PHP.
      */
-    protected function genLoopEndFlagCheck(): string
+    protected function genMultiLevelJumpCheck(bool $enclosingIsSwitch): string
     {
         $code = '';
         $indent = $this->getIndent();
@@ -227,7 +246,11 @@ trait LoopControlTrait
             $code .= "{$indent}if (_brk_flag > 0) { _brk_flag--; break; }" . PHP_EOL;
         }
         if ($this->context->hasMultiLevelContinue) {
-            $code .= "{$indent}if (_cnt_flag > 0) { _cnt_flag--; if (_cnt_flag == 0) continue; else break; }" . PHP_EOL;
+            if ($enclosingIsSwitch) {
+                $code .= "{$indent}if (_cnt_flag > 0) { _cnt_flag--; break; }" . PHP_EOL;
+            } else {
+                $code .= "{$indent}if (_cnt_flag > 0) { _cnt_flag--; if (_cnt_flag == 0) continue; else break; }" . PHP_EOL;
+            }
         }
         return $code;
     }

src/Parser/SwitchTrait.php

@@ -2,7 +2,7 @@
 /**
  * This file is part of TypePHP.
  *
- * Lowers switch cases, fallthrough, defaults, and loop-exit flags.
+ * Lowers switch cases, fallthrough, and defaults.
  */
 
 namespace TypePhp\Parser;
@@ -64,7 +64,6 @@ trait SwitchTrait
             }
             $this->indentLevel--;
             $code .= $this->getIndent() . '}' . PHP_EOL;
-            $code .= $this->genLoopEndFlagCheck();
             $this->indentLevel--;
             $code .= $this->getIndent() . '} while(0);' . PHP_EOL;
 
@@ -166,7 +165,6 @@ trait SwitchTrait
                 $code .= $this->getIndent() . '}' . PHP_EOL;
             }
         }
-        $code .= $this->genLoopEndFlagCheck();
         $this->indentLevel--;
         $code .= $this->getIndent() . '} while (0);';
 

tests/compiler/control_flow/break-continue-level-placement.phpt

@@ -0,0 +1,155 @@
+--TEST--
+Multi-level break/continue must skip trailing statements of enclosing bodies
+--FILE--
+<?php
+
+function nativeSwitchBreak(int $n): void
+{
+    // break 2 from a native (int-typed) switch inside a loop must exit the loop
+    for ($i = 0; $i < 3; $i++) {
+        echo "n-iter $i\n";
+        switch ($n) {
+            case 1:
+                echo "n-case\n";
+                break 2;
+            default:
+                break;
+        }
+        echo "n-after $i\n";
+    }
+    echo "native-switch-break-2: done\n";
+}
+
+function main(): void
+{
+    // break 2: statements after the inner loop must not run
+    foreach ([1, 2, 3] as $x) {
+        foreach ([1, 2, 3] as $y) {
+            echo "b2 inner $x.$y\n";
+            break 2;
+        }
+        echo "b2 leaked $x\n";
+    }
+    echo "break-2: done\n";
+
+    // continue 2: statements after the inner loop must not run
+    foreach ([1, 2] as $x) {
+        foreach ([1, 2] as $y) {
+            echo "c2 inner $x.$y\n";
+            continue 2;
+        }
+        echo "c2 leaked $x\n";
+    }
+    echo "continue-2: done\n";
+
+    // break 2 from a switch inside a loop: statements after the switch
+    // must not run and the loop must exit
+    for ($i = 0; $i < 3; $i++) {
+        echo "sw iter $i\n";
+        switch ($i) {
+            case 1:
+                echo "sw case $i\n";
+                break 2;
+            default:
+                break;
+        }
+        echo "sw after $i\n";
+    }
+    echo "switch-break-2: done\n";
+
+    // continue 2 from a switch inside a loop targets the loop
+    for ($i = 0; $i < 3; $i++) {
+        switch ($i) {
+            case 1:
+                echo "swc case $i\n";
+                continue 2;
+            default:
+                break;
+        }
+        echo "swc after $i\n";
+    }
+    echo "switch-continue-2: done\n";
+
+    // break 3 from a loop inside a switch inside a loop
+    for ($i = 0; $i < 3; $i++) {
+        switch ($i) {
+            case 0:
+                foreach ([1, 2] as $y) {
+                    echo "b3 deep $i.$y\n";
+                    break 3;
+                }
+                echo "b3 leaked after deep loop\n";
+                break;
+            default:
+                echo "b3 leaked default\n";
+                break;
+        }
+        echo "b3 leaked after switch $i\n";
+    }
+    echo "break-3-through-switch: done\n";
+
+    // continue 2 from a loop inside a switch acts as break on the switch
+    // level: statements after the switch must still run
+    for ($i = 0; $i < 2; $i++) {
+        switch ($i) {
+            case 0:
+                foreach ([1, 2] as $y) {
+                    echo "c2s deep $i.$y\n";
+                    continue 2;
+                }
+                echo "c2s leaked after deep loop\n";
+                break;
+            default:
+                break;
+        }
+        echo "c2s after switch $i\n";
+    }
+    echo "continue-2-targets-switch: done\n";
+
+    // continue 3 propagates through a switch up to the outer loop
+    for ($i = 0; $i < 2; $i++) {
+        switch ($i) {
+            case 0:
+                foreach ([1, 2] as $y) {
+                    echo "c3 deep $i.$y\n";
+                    continue 3;
+                }
+                echo "c3 leaked after deep loop\n";
+                break;
+            default:
+                break;
+        }
+        echo "c3 after switch $i\n";
+    }
+    echo "continue-3-through-switch: done\n";
+
+    nativeSwitchBreak(1);
+}
+?>
+--EXPECT--
+b2 inner 1.1
+break-2: done
+c2 inner 1.1
+c2 inner 2.1
+continue-2: done
+sw iter 0
+sw after 0
+sw iter 1
+sw case 1
+switch-break-2: done
+swc after 0
+swc case 1
+swc after 2
+switch-continue-2: done
+b3 deep 0.1
+break-3-through-switch: done
+c2s deep 0.1
+c2s after switch 0
+c2s after switch 1
+continue-2-targets-switch: done
+c3 deep 0.1
+c3 after switch 1
+continue-3-through-switch: done
+n-iter 0
+n-case
+native-switch-break-2: done

tests/compiler/control_flow/break-continue-level.phpt

@@ -37,9 +37,13 @@ while ($i < 3) {
 }
 echo "break-2-while: done\n";
 
-// continue 2 from nested while
+// continue 2 from nested while. The counter must advance before the
+// inner loop: continue 2 jumps straight to the outer condition, so a
+// trailing $i++ would never run and the loop would never terminate
+// (PHP itself loops forever on that variant).
 $i = 0;
 while ($i < 3) {
+    $i++;
     $j = 0;
     while ($j < 3) {
         $j++;
@@ -47,7 +51,6 @@ while ($i < 3) {
             continue 2;
         }
     }
-    $i++;
 }
 echo "continue-2-while: done\n";