minor #62072 [Console] Optimize mostRecentlyEnteredValue() method (dmitrijivanenko)

nicolas-grekas · nicolas-grekas · commit 2e7bd9a6a7a8 · 2025-10-15T10:16:12.000+02:00
This PR was merged into the 7.4 branch. Discussion ---------- [Console] Optimize mostRecentlyEnteredValue() method | Q | A | ------------- | --- | Branch? | 7.4 | Bug fix? | no | New feature? | no | Deprecations? | no | Issues | | License | MIT ## Performance optimization for `QuestionHelper::mostRecentlyEnteredValue()` This PR optimizes the `mostRecentlyEnteredValue()` private method in `QuestionHelper` by replacing inefficient array operations with direct string operations. ### What changed **Before:** ```php $choices = explode(',', $entered); // Creates entire array - O(n) time, O(n) space if ('' !== $lastChoice = trim($choices[\count($choices) - 1])) { return $lastChoice; } return $entered; ``` **After:** ```php $lastCommaPos = strrpos($entered, ','); // Find last comma position - O(n) if (false === $lastCommaPos) { return $entered; } $lastChoice = trim(substr($entered, $lastCommaPos + 1)); // Extract substring - O(m) where m = last element length return '' !== $lastChoice ? $lastChoice : $entered; ``` ### Why this is needed The current implementation creates an entire array with all comma-separated elements just to extract the last one. This is inefficient when we only need the last value. The optimized version: - Uses `strrpos()` to find the last comma position directly - Uses `substr()` to extract only the needed portion - Reduces memory usage from O(n) to O(m) where m is typically much smaller than n - 20-40% faster in typical usage scenarios due to reduced memory allocations and fewer operations - Avoids array structure overhead ### Performance benchmark results Benchmarked with 100,000 iterations per test case on PHP 8.4: | Test Case | Old Time | New Time | Improvement | Speedup | |-----------|----------|----------|-------------|---------| | No comma | 0.0034s | 0.0034s | - | - | | One comma | 0.0105s | 0.0089s | **+15.2%** | 1.18x | | Two commas | 0.0117s | 0.0088s | **+25.0%** | 1.33x | | Three commas | 0.0129s | 0.0094s | **+27.1%** | 1.37x | | Five commas | 0.0106s | 0.0080s | **+23.9%** | 1.31x | | Ten commas | 0.0147s | 0.0079s | **+46.4%** | 1.87x | | With spaces | 0.0122s | 0.0094s | **+23.2%** | 1.30x | | Empty last | 0.0109s | 0.0078s | **+28.7%** | 1.40x | | Unicode | 0.0116s | 0.0090s | **+22.2%** | 1.29x | | Real-world example | 0.0128s | 0.0090s | **+30.0%** | 1.43x | **Average improvement: ~25% faster** across typical use cases. <details> <summary>Benchmark code (click to expand)</summary> ```php <?php // Old implementation (using explode + count) function oldImplementation(string $entered): string { if (!str_contains($entered, ',')) { return $entered; } $choices = explode(',', $entered); if ('' !== $lastChoice = trim($choices[\count($choices) - 1])) { return $lastChoice; } return $entered; } // New implementation (using strrpos + substr) function newImplementation(string $entered): string { if (!str_contains($entered, ',')) { return $entered; } $lastCommaPos = strrpos($entered, ','); if (false === $lastCommaPos) { return $entered; } $lastChoice = trim(substr($entered, $lastCommaPos + 1)); return '' !== $lastChoice ? $lastChoice : $entered; } // Test cases $testCases = [ 'No comma' => 'SimpleValue', 'One comma' => 'First,Second', 'Two commas' => 'First,Second,Third', 'Three commas' => 'First,Second,Third,Fourth', 'Five commas' => 'a,b,c,d,e,f', 'Ten commas' => 'a,b,c,d,e,f,g,h,i,j,k', 'With spaces' => 'Superman, Batman, Spiderman', 'Empty last' => 'First,Second,', 'Unicode' => 'привет,мир,тест', 'Real-world example' => 'AcmeDemoBundle,AsseticBundle,SecurityBundle,FooBundle', ]; $iterations = 100000; foreach ($testCases as $name => $input) { // Benchmark old implementation $startOld = microtime(true); for ($i = 0; $i < $iterations; $i++) { oldImplementation($input); } $timeOld = microtime(true) - $startOld; // Benchmark new implementation $startNew = microtime(true); for ($i = 0; $i < $iterations; $i++) { newImplementation($input); } $timeNew = microtime(true) - $startNew; $improvement = (($timeOld - $timeNew) / $timeOld) * 100; $speedup = $timeOld / $timeNew; printf( "%-25s Old: %7.4fs | New: %7.4fs | Improvement: %+6.1f%% (%.2fx)\n", $name . ':', $timeOld, $timeNew, $improvement, $speedup ); } ``` </details> ### Backward compatibility - ✅ No API changes - ✅ No behavioral changes - ✅ All existing tests pass - ✅ Works with all encodings (UTF-8, UTF-16, etc.) - ✅ Handles all edge cases identically to the previous implementation This method is used internally during interactive console input for multiselect choice questions with autocomplete, so the performance improvement benefits all interactive console applications. Commits ------- 85737e3 [Console] Optimize mostRecentlyEnteredValue() method
diff --git a/src/Symfony/Component/Console/Helper/QuestionHelper.php b/src/Symfony/Component/Console/Helper/QuestionHelper.php
@@ -379,12 +379,13 @@ private function mostRecentlyEnteredValue(string $entered): string
             return $entered;
         }
 
-        $choices = explode(',', $entered);
-        if ('' !== $lastChoice = trim($choices[\count($choices) - 1])) {
-            return $lastChoice;
+        if (false === $lastCommaPos = strrpos($entered, ',')) {
+            return $entered;
         }
 
-        return $entered;
+        $lastChoice = trim(substr($entered, $lastCommaPos + 1));
+
+        return '' !== $lastChoice ? $lastChoice : $entered;
     }
 
     /**
