diff --git a/src/Composer/Command/PackageDiscoveryTrait.php b/src/Composer/Command/PackageDiscoveryTrait.php
index 5e210bd7c..7b0716f55 100644
--- a/src/Composer/Command/PackageDiscoveryTrait.php
+++ b/src/Composer/Command/PackageDiscoveryTrait.php
@@ -97,6 +97,10 @@ trait PackageDiscoveryTrait
             $io = $this->getIO();
 
             foreach ($requires as $requirement) {
+                if (isset($requirement['version']) && Preg::isMatch('{^\d+(\.\d+)?$}', $requirement['version'])) {
+                    $io->writeError('<warning>The "'.$requirement['version'].'" constraint for "'.$requirement['name'].'" appears too strict and will likely not match what you want. See https://getcomposer.org/constraints');
+                }
+
                 if (!isset($requirement['version'])) {
                     // determine the best version automatically
                     list($name, $version) = $this->findBestVersionAndNameForPackage($input, $requirement['name'], $platformRepo, $preferredStability, null, null, $fixed);
diff --git a/src/Composer/DependencyResolver/SolverProblemsException.php b/src/Composer/DependencyResolver/SolverProblemsException.php
index ea8c86af5..cd4f49075 100644
--- a/src/Composer/DependencyResolver/SolverProblemsException.php
+++ b/src/Composer/DependencyResolver/SolverProblemsException.php
@@ -117,9 +117,9 @@ class SolverProblemsException extends \RuntimeException
             return '';
         }
 
-        $ignoreExtensionsArguments = implode(" ", array_map(function ($extension) {
+        $ignoreExtensionsArguments = implode(" ", array_map(static function ($extension) {
             return "--ignore-platform-req=$extension";
-        }, $missingExtensions));
+        }, array_unique($missingExtensions)));
 
         $text = "To enable extensions, verify that they are enabled in your .ini files:\n    - ";
         $text .= implode("\n    - ", $paths);
diff --git a/src/Composer/Factory.php b/src/Composer/Factory.php
index dd5e4219b..d4ae079d2 100644
--- a/src/Composer/Factory.php
+++ b/src/Composer/Factory.php
@@ -287,6 +287,11 @@ class Factory
      */
     public function createComposer(IOInterface $io, $localConfig = null, $disablePlugins = false, ?string $cwd = null, bool $fullLoad = true, bool $disableScripts = false)
     {
+        // if a custom composer.json path is given, we change the default cwd to be that file's directory
+        if (is_string($localConfig) && is_file($localConfig) && null === $cwd) {
+            $cwd = dirname($localConfig);
+        }
+
         $cwd = $cwd ?? Platform::getCwd(true);
 
         // load Composer configuration
diff --git a/tests/Composer/Test/Fixtures/installer/solver-problems-with-disabled-platform.test b/tests/Composer/Test/Fixtures/installer/solver-problems-with-disabled-platform.test
index 9fab8e4cb..2c698a2a6 100644
--- a/tests/Composer/Test/Fixtures/installer/solver-problems-with-disabled-platform.test
+++ b/tests/Composer/Test/Fixtures/installer/solver-problems-with-disabled-platform.test
@@ -81,7 +81,6 @@ Your requirements could not be resolved to an installable set of packages.
 To enable extensions, verify that they are enabled in your .ini files:
 __inilist__
 You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode.
-Alternatively, you can run Composer with `--ignore-platform-req=ext-foobar --ignore-platform-req=ext-pcre --ignore-platform-req=ext-foobar --ignore-platform-req=ext-pcre` to temporarily ignore these required extensions.
+Alternatively, you can run Composer with `--ignore-platform-req=ext-foobar --ignore-platform-req=ext-pcre` to temporarily ignore these required extensions.
 
 --EXPECT--
-