FPPP: Support removing nodes from start of list

Author: nikic

lib/PhpParser/Internal/TokenStream.php

@@ -33,7 +33,7 @@ public function __construct(array $tokens) {
      * @return bool
      */
     public function haveParens(int $startPos, int $endPos) : bool {
-        return $this->haveTokenImmediativelyBefore($startPos, '(')
+        return $this->haveTokenImmediatelyBefore($startPos, '(')
             && $this->haveTokenImmediatelyAfter($endPos, ')');
     }
 
@@ -46,7 +46,7 @@ public function haveParens(int $startPos, int $endPos) : bool {
      * @return bool
      */
     public function haveBraces(int $startPos, int $endPos) : bool {
-        return $this->haveTokenImmediativelyBefore($startPos, '{')
+        return $this->haveTokenImmediatelyBefore($startPos, '{')
             && $this->haveTokenImmediatelyAfter($endPos, '}');
     }
 
@@ -60,7 +60,7 @@ public function haveBraces(int $startPos, int $endPos) : bool {
      *
      * @return bool Whether the expected token was found
      */
-    public function haveTokenImmediativelyBefore(int $pos, $expectedTokenType) : bool {
+    public function haveTokenImmediatelyBefore(int $pos, $expectedTokenType) : bool {
         $tokens = $this->tokens;
         $pos--;
         for (; $pos >= 0; $pos--) {

lib/PhpParser/PrettyPrinterAbstract.php

@@ -706,6 +706,7 @@ protected function pArray(
         $insertStr = $this->listInsertionMap[$mapKey] ?? null;
 
         $beforeFirstKeepOrReplace = true;
+        $skipRemovedNode = false;
         $delayedAdd = [];
         $lastElemIndentLevel = $this->indentLevel;
 
@@ -797,7 +798,7 @@ protected function pArray(
                         $commentStartPos, $itemStartPos, $indentAdjustment);
 
                     $delayedAdd = [];
-                } else {
+                } else if (!$skipRemovedNode) {
                     $result .= $this->origTokens->getTokenCode(
                         $pos, $itemStartPos, $indentAdjustment);
                 }
@@ -806,6 +807,9 @@ protected function pArray(
                     // Add new comments
                     $result .= $this->pComments($comments) . $this->nl;
                 }
+
+                // If we had to remove anything, we have done so now.
+                $skipRemovedNode = false;
             } elseif ($diffType === DiffElem::TYPE_ADD) {
                 if (null === $insertStr) {
                     // We don't have insertion information for this list type
@@ -839,18 +843,42 @@ protected function pArray(
                     $result .= $insertStr;
                 }
             } elseif ($diffType === DiffElem::TYPE_REMOVE) {
-                if ($i === 0) {
-                    // TODO Handle removal at the start
-                    return null;
-                }
-
                 if (!$origArrItem instanceof Node) {
                     // We only support removal for nodes
                     return null;
                 }
 
+                $itemStartPos = $origArrItem->getStartTokenPos();
                 $itemEndPos = $origArrItem->getEndTokenPos();
-                \assert($itemEndPos >= 0);
+                \assert($itemStartPos >= 0 && $itemEndPos >= 0);
+
+                // Consider comments part of the node.
+                $origComments = $origArrItem->getComments();
+                if ($origComments) {
+                    $itemStartPos = $origComments[0]->getStartTokenPos();
+                }
+
+                if ($i === 0) {
+                    // If we're removing from the start, keep the tokens before the node and drop those after it,
+                    // instead of the other way around.
+                    $result .= $this->origTokens->getTokenCode(
+                        $pos, $itemStartPos, $indentAdjustment);
+                    $skipRemovedNode = true;
+
+                    if ($this->origTokens->haveTokenImmediatelyAfter($itemEndPos, '{')
+                        || $this->origTokens->haveTokenImmediatelyAfter($itemEndPos, '}')) {
+                        // We'd remove the brace of a code block.
+                        // TODO: Preserve formatting.
+                        return null;
+                    }
+                } else {
+                    if ($this->origTokens->haveTokenImmediatelyBefore($itemStartPos, '{')
+                        || $this->origTokens->haveTokenImmediatelyBefore($itemStartPos, '}')) {
+                        // We'd remove the brace of a code block.
+                        // TODO: Preserve formatting.
+                        return null;
+                    }
+                }
 
                 $pos = $itemEndPos + 1;
                 continue;
@@ -869,6 +897,11 @@ protected function pArray(
             $pos = $itemEndPos + 1;
         }
 
+        if ($skipRemovedNode) {
+            // TODO: Support removing single node.
+            return null;
+        }
+
         if (!empty($delayedAdd)) {
             if (!isset($this->emptyListInsertionMap[$mapKey])) {
                 return null;

test/code/formatPreservation/basic.test

@@ -106,7 +106,6 @@ $stmts[2] = $tmp;
 array_splice($stmts, 0, 1, []);
 -----
 <?php
-
 function test() {
     call2(
         $foo

test/code/formatPreservation/listRemoval.test

@@ -49,4 +49,66 @@ array_pop($stmts[0]->returnType->types);
 -----
 <?php
 function test(): A
-|B {}
+|B {}
+-----
+<?php $a; $b; $c;
+-----
+array_splice($stmts, 0, 1, []);
+-----
+<?php $b; $c;
+-----
+<?php $a; $b; $c;
+-----
+array_splice($stmts, 0, 2, []);
+-----
+<?php $c;
+-----
+<?php
+{ $x; }
+$y;
+-----
+array_splice($stmts, 0, 1, []);
+-----
+<?php
+
+$y;
+-----
+<?php
+$x;
+{ $y; }
+-----
+array_splice($stmts, 0, 1, []);
+-----
+<?php
+
+$y;
+-----
+<?php
+$x;
+{ $y; }
+-----
+array_pop($stmts);
+-----
+<?php
+
+$x;
+-----
+<?php
+{ $x; }
+$y;
+-----
+array_pop($stmts);
+-----
+<?php
+
+$x;
+-----
+<?php
+// Foo
+$x;
+$y;
+-----
+array_splice($stmts, 0, 1, []);
+-----
+<?php
+$y;