Fix #10575 (#10576)

Refactor the whole cleanChanges/getLocalChanges code to be more strict with null returns

Co-authored-by: Jordi Boggiano <j.boggiano@seld.be>

src/Composer/Command/StatusCommand.php

@@ -109,7 +109,7 @@ EOT
                     $errors[$targetDir] = $targetDir . ' is a symbolic link.';
                 }
 
-                if ($changes = $downloader->getLocalChanges($package, $targetDir)) {
+                if (null !== ($changes = $downloader->getLocalChanges($package, $targetDir))) {
                     $errors[$targetDir] = $changes;
                 }
             }

src/Composer/Downloader/FileDownloader.php

@@ -500,7 +500,7 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
             $comparer->setSource($targetDir.'_compare');
             $comparer->setUpdate($targetDir);
             $comparer->doCompare();
-            $output = $comparer->getChanged(true, true);
+            $output = $comparer->getChangedAsString(true);
             $this->filesystem->removeDirectory($targetDir.'_compare');
         } catch (\Exception $e) {
         }
@@ -511,6 +511,8 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
             throw $e;
         }
 
-        return trim($output);
+        $output = trim($output);
+
+        return strlen($output) > 0 ? $output : null;
     }
 }

src/Composer/Downloader/FossilDownloader.php

@@ -92,7 +92,9 @@ class FossilDownloader extends VcsDownloader
 
         $this->process->execute('fossil changes', $output, realpath($path));
 
-        return trim($output) ?: null;
+        $output = trim($output);
+
+        return strlen($output) > 0 ? $output : null;
     }
 
     /**

src/Composer/Downloader/GitDownloader.php

@@ -225,7 +225,9 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
             throw new \RuntimeException('Failed to execute ' . $command . "\n\n" . $this->process->getErrorOutput());
         }
 
-        return trim($output) ?: null;
+        $output = trim($output);
+
+        return strlen($output) > 0 ? $output : null;
     }
 
     /**
@@ -338,7 +340,7 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
             throw new \RuntimeException('Source directory ' . $path . ' has unpushed changes on the current branch: '."\n".$unpushed);
         }
 
-        if (!$changes = $this->getLocalChanges($package, $path)) {
+        if (null === ($changes = $this->getLocalChanges($package, $path))) {
             return \React\Promise\resolve();
         }
 

src/Composer/Downloader/HgDownloader.php

@@ -90,7 +90,9 @@ class HgDownloader extends VcsDownloader
 
         $this->process->execute('hg st', $output, realpath($path));
 
-        return trim($output) ?: null;
+        $output = trim($output);
+
+        return strlen($output) > 0 ? $output : null;
     }
 
     /**

src/Composer/Downloader/SvnDownloader.php

@@ -132,7 +132,7 @@ class SvnDownloader extends VcsDownloader
      */
     protected function cleanChanges(PackageInterface $package, string $path, bool $update): PromiseInterface
     {
-        if (!$changes = $this->getLocalChanges($package, $path)) {
+        if (null === ($changes = $this->getLocalChanges($package, $path))) {
             return \React\Promise\resolve();
         }
 

src/Composer/Package/Comparer/Comparer.php

@@ -49,12 +49,11 @@ class Comparer
     }
 
     /**
-     * @param bool $toString
      * @param bool $explicated
      *
-     * @return array{changed?: string[], removed?: string[], added?: string[]}|string|false false if no change, string only if $toString is true
+     * @return array{changed?: string[], removed?: string[], added?: string[]}|false false if no change
      */
-    public function getChanged(bool $toString = false, bool $explicated = false)
+    public function getChanged(bool $explicated = false)
     {
         $changed = $this->changed;
         if (!count($changed)) {
@@ -68,17 +67,29 @@ class Comparer
             }
         }
 
-        if ($toString) {
+        return $changed;
-            $strings = array();
+    }
-            foreach ($changed as $sectionKey => $itemSection) {
+
-                foreach ($itemSection as $itemKey => $item) {
+    /**
-                    $strings[] = $item."\r\n";
+     * @param bool $explicated
-                }
+     *
+     * @return string empty string if no changes
+     */
+    public function getChangedAsString(bool $toString = false, bool $explicated = false): string
+    {
+        $changed = $this->getChanged($explicated);
+        if (false === $changed) {
+            return '';
+        }
+
+        $strings = array();
+        foreach ($changed as $sectionKey => $itemSection) {
+            foreach ($itemSection as $itemKey => $item) {
+                $strings[] = $item."\r\n";
             }
-            $changed = implode("\r\n", $strings);
         }
 
-        return $changed;
+        return trim(implode("\r\n", $strings));
     }
 
     /**