diff --git a/php/WP_CLI/Bootstrap/DefineProtectedCommands.php b/php/WP_CLI/Bootstrap/DefineProtectedCommands.php
index f56da5a65e..5a77a5d62d 100644
--- a/php/WP_CLI/Bootstrap/DefineProtectedCommands.php
+++ b/php/WP_CLI/Bootstrap/DefineProtectedCommands.php
@@ -40,7 +40,7 @@ public function process( BootstrapState $state ) {
 	private function get_protected_commands() {
 		return array(
 			'cli info',
-		    'package',
+			'package',
 		);
 	}
 
diff --git a/php/class-wp-cli.php b/php/class-wp-cli.php
index 649a071027..872e88b6ed 100644
--- a/php/class-wp-cli.php
+++ b/php/class-wp-cli.php
@@ -381,9 +381,9 @@ private static function wp_hook_build_unique_id( $tag, $function, $priority ) {
 	 * @access public
 	 * @category Registration
 	 *
-	 * @param string $name Name for the command (e.g. "post list" or "site empty").
-	 * @param string $callable Command implementation as a class, function or closure.
-	 * @param array $args {
+	 * @param string   $name Name for the command (e.g. "post list" or "site empty").
+	 * @param callable $callable Command implementation as a class, function or closure.
+	 * @param array    $args {
 	 *    Optional. An associative array with additional registration parameters.
 	 *
 	 *    @type callable $before_invoke Callback to execute before invoking the command.
diff --git a/php/commands/help.php b/php/commands/help.php
index 9a1c1a5259..23a477d839 100644
--- a/php/commands/help.php
+++ b/php/commands/help.php
@@ -60,20 +60,28 @@ private static function show_help( $command ) {
 		$wordwrap_width = \cli\Shell::columns();
 
 		// Wordwrap with indent.
-		$out = preg_replace_callback( '/^( *)([^\n]+)\n/m', function ( $matches ) use ( $wordwrap_width ) {
-			return $matches[1] . str_replace( "\n", "\n{$matches[1]}", wordwrap( $matches[2], $wordwrap_width - strlen( $matches[1] ) ) ) . "\n";
-		}, $out );
+		$out = preg_replace_callback(
+			'/^( *)([^\n]+)\n/m',
+			function ( $matches ) use ( $wordwrap_width ) {
+				return $matches[1] . str_replace( "\n", "\n{$matches[1]}", wordwrap( $matches[2], $wordwrap_width - strlen( $matches[1] ) ) ) . "\n";
+			},
+			$out
+		);
 
 		if ( $subcommands ) {
 			// Wordwrap with column indent.
-			$subcommands = preg_replace_callback( '/^(' . $column_subpattern . ')([^\n]+)\n/m', function ( $matches ) use ( $wordwrap_width, $tab ) {
-				// Need to de-tab for wordwrapping to work properly.
-				$matches[1] = str_replace( "\t", $tab, $matches[1] );
-				$matches[2] = str_replace( "\t", $tab, $matches[2] );
-				$padding_len = strlen( $matches[1] );
-				$padding = str_repeat( ' ', $padding_len );
-				return $matches[1] . str_replace( "\n", "\n$padding", wordwrap( $matches[2], $wordwrap_width - $padding_len ) ) . "\n";
-			}, $subcommands );
+			$subcommands = preg_replace_callback(
+				'/^(' . $column_subpattern . ')([^\n]+)\n/m',
+				function ( $matches ) use ( $wordwrap_width, $tab ) {
+					// Need to de-tab for wordwrapping to work properly.
+					$matches[1] = str_replace( "\t", $tab, $matches[1] );
+					$matches[2] = str_replace( "\t", $tab, $matches[2] );
+					$padding_len = strlen( $matches[1] );
+					$padding = str_repeat( ' ', $padding_len );
+					return $matches[1] . str_replace( "\n", "\n$padding", wordwrap( $matches[2], $wordwrap_width - $padding_len ) ) . "\n";
+				},
+				$subcommands
+			);
 
 			// Put subcommands back.
 			$out = str_replace( $subcommands_header, $subcommands, $out );
@@ -111,7 +119,7 @@ private static function pass_through_pager( $out ) {
 		}
 
 		// convert string to file handle
-		$fd = fopen( "php://temp", "r+" );
+		$fd = fopen( 'php://temp', 'r+' );
 		fputs( $fd, $out );
 		rewind( $fd );
 
@@ -171,8 +179,9 @@ private static function get_max_len( $strings ) {
 		$max_len = 0;
 		foreach ( $strings as $str ) {
 			$len = strlen( $str );
-			if ( $len > $max_len )
+			if ( $len > $max_len ) {
 				$max_len = $len;
+			}
 		}
 
 		return $max_len;
diff --git a/php/commands/src/CLI_Command.php b/php/commands/src/CLI_Command.php
index 3e75509f01..67f8c83f37 100644
--- a/php/commands/src/CLI_Command.php
+++ b/php/commands/src/CLI_Command.php
@@ -192,7 +192,7 @@ public function check_update( $_, $assoc_args ) {
 				array( 'version', 'update_type', 'package_url' )
 			);
 			$formatter->display_items( $updates );
-		} else if ( empty( $assoc_args['format'] ) || 'table' == $assoc_args['format'] ) {
+		} elseif ( empty( $assoc_args['format'] ) || 'table' == $assoc_args['format'] ) {
 			$update_type = $this->get_update_type_str( $assoc_args );
 			WP_CLI::success( "WP-CLI is at the latest{$update_type}version." );
 		}
@@ -244,22 +244,22 @@ public function check_update( $_, $assoc_args ) {
 	 */
 	public function update( $_, $assoc_args ) {
 		if ( ! Utils\inside_phar() ) {
-			WP_CLI::error( "You can only self-update Phar files." );
+			WP_CLI::error( 'You can only self-update Phar files.' );
 		}
 
 		$old_phar = realpath( $_SERVER['argv'][0] );
 
 		if ( ! is_writable( $old_phar ) ) {
-			WP_CLI::error( sprintf( "%s is not writable by current user.", $old_phar ) );
-		} else if ( ! is_writeable( dirname( $old_phar ) ) ) {
-			WP_CLI::error( sprintf( "%s is not writable by current user.", dirname( $old_phar ) ) );
+			WP_CLI::error( sprintf( '%s is not writable by current user.', $old_phar ) );
+		} elseif ( ! is_writeable( dirname( $old_phar ) ) ) {
+			WP_CLI::error( sprintf( '%s is not writable by current user.', dirname( $old_phar ) ) );
 		}
 
 		if ( Utils\get_flag_value( $assoc_args, 'nightly' ) ) {
 			WP_CLI::confirm( sprintf( 'You have version %s. Would you like to update to the latest nightly?', WP_CLI_VERSION ), $assoc_args );
 			$download_url = 'https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli-nightly.phar';
 			$md5_url = 'https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli-nightly.phar.md5';
-		} else if ( Utils\get_flag_value( $assoc_args, 'stable' ) ) {
+		} elseif ( Utils\get_flag_value( $assoc_args, 'stable' ) ) {
 			WP_CLI::confirm( sprintf( 'You have version %s. Would you like to update to the latest stable release?', WP_CLI_VERSION ), $assoc_args );
 			$download_url = 'https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar';
 			$md5_url = 'https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar.md5';
@@ -283,7 +283,7 @@ public function update( $_, $assoc_args ) {
 
 		WP_CLI::log( sprintf( 'Downloading from %s...', $download_url ) );
 
-		$temp = \WP_CLI\Utils\get_temp_dir() . uniqid('wp_') . '.phar';
+		$temp = \WP_CLI\Utils\get_temp_dir() . uniqid( 'wp_' ) . '.phar';
 
 		$headers = array();
 		$options = array(
@@ -320,18 +320,18 @@ public function update( $_, $assoc_args ) {
 		$mode = fileperms( $old_phar ) & 511;
 
 		if ( false === @chmod( $temp, $mode ) ) {
-			WP_CLI::error( sprintf( "Cannot chmod %s.", $temp ) );
+			WP_CLI::error( sprintf( 'Cannot chmod %s.', $temp ) );
 		}
 
 		class_exists( '\cli\Colors' ); // This autoloads \cli\Colors - after we move the file we no longer have access to this class.
 
 		if ( false === @rename( $temp, $old_phar ) ) {
-			WP_CLI::error( sprintf( "Cannot move %s to %s", $temp, $old_phar ) );
+			WP_CLI::error( sprintf( 'Cannot move %s to %s', $temp, $old_phar ) );
 		}
 
 		if ( Utils\get_flag_value( $assoc_args, 'nightly' ) ) {
 			$updated_version = 'the latest nightly release';
-		} else if ( Utils\get_flag_value( $assoc_args, 'stable' ) ) {
+		} elseif ( Utils\get_flag_value( $assoc_args, 'stable' ) ) {
 			$updated_version = 'the latest stable release';
 		} else {
 			$updated_version = $newest['version'];
@@ -359,7 +359,7 @@ private function get_updates( $assoc_args ) {
 		$response = Utils\http_request( 'GET', $url, null, $headers, $options );
 
 		if ( ! $response->success || 200 !== $response->status_code ) {
-			WP_CLI::error( sprintf( "Failed to get latest version (HTTP code %d).", $response->status_code ) );
+			WP_CLI::error( sprintf( 'Failed to get latest version (HTTP code %d).', $response->status_code ) );
 		}
 
 		$release_data = json_decode( $response->body );
@@ -393,13 +393,13 @@ private function get_updates( $assoc_args ) {
 			);
 		}
 
-		foreach( $updates as $type => $value ) {
+		foreach ( $updates as $type => $value ) {
 			if ( empty( $value ) ) {
 				unset( $updates[ $type ] );
 			}
 		}
 
-		foreach( array( 'major', 'minor', 'patch' ) as $type ) {
+		foreach ( array( 'major', 'minor', 'patch' ) as $type ) {
 			if ( true === \WP_CLI\Utils\get_flag_value( $assoc_args, $type ) ) {
 				return ! empty( $updates[ $type ] ) ? array( $updates[ $type ] ) : false;
 			}
@@ -409,7 +409,7 @@ private function get_updates( $assoc_args ) {
 			$version_url = 'https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/NIGHTLY_VERSION';
 			$response = Utils\http_request( 'GET', $version_url );
 			if ( ! $response->success || 200 !== $response->status_code ) {
-				WP_CLI::error( sprintf( "Failed to get current nightly version (HTTP code %d)", $response->status_code ) );
+				WP_CLI::error( sprintf( 'Failed to get current nightly version (HTTP code %d)', $response->status_code ) );
 			}
 			$nightly_version = trim( $response->body );
 			if ( WP_CLI_VERSION != $nightly_version ) {
@@ -467,12 +467,12 @@ function param_dump( $_, $assoc_args ) {
 			$config = \WP_CLI::get_configurator()->to_array();
 			// Copy current config values to $spec
 			foreach ( $spec as $key => $value ) {
-				if ( isset( $config[0][$key] ) ) {
-					$current = $config[0][$key];
+				if ( isset( $config[0][ $key ] ) ) {
+					$current = $config[0][ $key ];
 				} else {
-					$current = NULL;
+					$current = null;
 				}
-				$spec[$key]['current'] = $current;
+				$spec[ $key ]['current'] = $current;
 			}
 		}
 
@@ -566,7 +566,7 @@ public function alias( $_, $assoc_args ) {
 	 */
 	private function get_update_type_str( $assoc_args ) {
 		$update_type = ' ';
-		foreach( array( 'major', 'minor', 'patch' ) as $type ) {
+		foreach ( array( 'major', 'minor', 'patch' ) as $type ) {
 			if ( true === \WP_CLI\Utils\get_flag_value( $assoc_args, $type ) ) {
 				$update_type = ' ' . $type . ' ';
 				break;
diff --git a/php/utils.php b/php/utils.php
index fc8d0df84b..ed7a2282c1 100644
--- a/php/utils.php
+++ b/php/utils.php
@@ -908,24 +908,125 @@ function isPiped() {
  * Has no effect on paths which do not use glob patterns.
  *
  * @param string|array $paths Single path as a string, or an array of paths.
- * @param int          $flags Flags to pass to glob.
+ * @param int          $flags Optional. Flags to pass to glob. Defaults to GLOB_BRACE.
  *
  * @return array Expanded paths.
  */
-function expand_globs( $paths, $flags = GLOB_BRACE ) {
+function expand_globs( $paths, $flags = 'default' ) {
+	// Compatibility for systems without GLOB_BRACE.
+	$glob_func = 'glob';
+	if ( 'default' === $flags ) {
+		if ( ! defined( 'GLOB_BRACE' ) || getenv( 'WP_CLI_TEST_EXPAND_GLOBS_NO_GLOB_BRACE' ) ) {
+			$glob_func = 'WP_CLI\Utils\glob_brace';
+		} else {
+			$flags = GLOB_BRACE;
+		}
+	}
+
 	$expanded = array();
 
 	foreach ( (array) $paths as $path ) {
 		$matching = array( $path );
 
 		if ( preg_match( '/[' . preg_quote( '*?[]{}!', '/' ) . ']/', $path ) ) {
-			$matching = glob( $path, $flags ) ?: array();
+			$matching = $glob_func( $path, $flags ) ?: array();
 		}
-
 		$expanded = array_merge( $expanded, $matching );
 	}
 
-	return array_unique( $expanded );
+	return array_values( array_unique( $expanded ) );
+}
+
+/**
+ * Simulate a `glob()` with the `GLOB_BRACE` flag set. For systems (eg Alpine Linux) built against a libc library (eg https://www.musl-libc.org/) that lacks it.
+ * Copied and adapted from Zend Framework's `Glob::fallbackGlob()` and Glob::nextBraceSub()`.
+ *
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link      http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ *
+ * @param string $pattern Filename pattern.
+ * @param void $dummy_flags Not used.
+ *
+ * @return array Array of paths.
+ */
+function glob_brace( $pattern, $dummy_flags = null ) {
+
+	static $next_brace_sub;
+	if ( ! $next_brace_sub ) {
+		// Find the end of the subpattern in a brace expression.
+		$next_brace_sub = function ( $pattern, $current ) {
+			$length  = strlen( $pattern );
+			$depth   = 0;
+
+			while ( $current < $length ) {
+				if ( '\\' === $pattern[ $current ] ) {
+					if ( ++$current === $length ) {
+						break;
+					}
+					$current++;
+				} else {
+					if ( ( '}' === $pattern[ $current ] && $depth-- === 0 ) || ( ',' === $pattern[ $current ] && 0 === $depth ) ) {
+						break;
+					} elseif ( '{' === $pattern[ $current++ ] ) {
+						$depth++;
+					}
+				}
+			}
+
+			return $current < $length ? $current : null;
+		};
+	}
+
+	$length = strlen( $pattern );
+
+	// Find first opening brace.
+	for ( $begin = 0; $begin < $length; $begin++ ) {
+		if ( '\\' === $pattern[ $begin ] ) {
+			$begin++;
+		} elseif ( '{' === $pattern[ $begin ] ) {
+			break;
+		}
+	}
+
+	// Find comma or matching closing brace.
+	if ( null === ( $next = $next_brace_sub( $pattern, $begin + 1 ) ) ) {
+		return glob( $pattern );
+	}
+
+	$rest = $next;
+
+	// Point `$rest` to matching closing brace.
+	while ( '}' !== $pattern[ $rest ] ) {
+		if ( null === ( $rest = $next_brace_sub( $pattern, $rest + 1 ) ) ) {
+			return glob( $pattern );
+		}
+	}
+
+	$paths = array();
+	$p = $begin + 1;
+
+	// For each comma-separated subpattern.
+	do {
+		$subpattern = substr( $pattern, 0, $begin )
+					. substr( $pattern, $p, $next - $p )
+					. substr( $pattern, $rest + 1 );
+
+		if ( ( $result = glob_brace( $subpattern ) ) ) {
+			$paths = array_merge( $paths, $result );
+		}
+
+		if ( '}' === $pattern[ $next ] ) {
+			break;
+		}
+
+		$p    = $next + 1;
+		$next = $next_brace_sub( $pattern, $p );
+	} while ( null !== $next );
+
+	return array_values( array_unique( $paths ) );
 }
 
 /**
diff --git a/tests/data/expand_globs/bar.ab1 b/tests/data/expand_globs/bar.ab1
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/bar.ab2 b/tests/data/expand_globs/bar.ab2
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/baz.ab1 b/tests/data/expand_globs/baz.ab1
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/baz.ac1 b/tests/data/expand_globs/baz.ac1
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/baz.efg2 b/tests/data/expand_globs/baz.efg2
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/foo.ab1 b/tests/data/expand_globs/foo.ab1
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/foo.ab2 b/tests/data/expand_globs/foo.ab2
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/foo.efg1 b/tests/data/expand_globs/foo.efg1
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/data/expand_globs/foo.efg2 b/tests/data/expand_globs/foo.efg2
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/test-utils.php b/tests/test-utils.php
index d68469d74a..756b8757af 100644
--- a/tests/test-utils.php
+++ b/tests/test-utils.php
@@ -494,4 +494,41 @@ public function dataPastTenseVerb() {
 		);
 	}
 
+	/**
+	 * @dataProvider dataExpandGlobs
+	 */
+	public function testExpandGlobs( $path, $expected ) {
+		$expand_globs_no_glob_brace = getenv( 'WP_CLI_TEST_EXPAND_GLOBS_NO_GLOB_BRACE' );
+
+		$dir = __DIR__ . '/data/expand_globs/';
+		$expected = array_map( function ( $v ) use ( $dir ) { return $dir . $v; }, $expected );
+
+		putenv( 'WP_CLI_TEST_EXPAND_GLOBS_NO_GLOB_BRACE=0' );
+		$out = Utils\expand_globs( $dir . $path );
+		$this->assertSame( $expected, $out );
+
+		putenv( 'WP_CLI_TEST_EXPAND_GLOBS_NO_GLOB_BRACE=1' );
+		$out = Utils\expand_globs( $dir . $path );
+		$this->assertSame( $expected, $out );
+
+		putenv( false === $expand_globs_no_glob_brace ? 'WP_CLI_TEST_EXPAND_GLOBS_NO_GLOB_BRACE' : "WP_CLI_TEST_EXPAND_GLOBS_NO_GLOB_BRACE=$expand_globs_no_glob_brace" );
+	}
+
+	public function dataExpandGlobs() {
+		// Files in "data/expand_globs": foo.ab1, foo.ab2, foo.efg1, foo.efg2, bar.ab1, bar.ab2, baz.ab1, baz.ac1, baz.efg2.
+		return array(
+			array( 'foo.ab1', array( 'foo.ab1' ) ),
+			array( '{foo,bar}.ab1', array( 'foo.ab1', 'bar.ab1' ) ),
+			array( '{foo,baz}.a{b,c}1', array( 'foo.ab1', 'baz.ab1' , 'baz.ac1' ) ),
+			array( '{foo,baz}.{ab,ac}1', array( 'foo.ab1', 'baz.ab1' , 'baz.ac1' ) ),
+			array( '{foo,bar}.{ab1,efg1}', array( 'foo.ab1', 'foo.efg1', 'bar.ab1' ) ),
+			array( '{foo,bar,baz}.{ab,ac,efg}1', array( 'foo.ab1', 'foo.efg1', 'bar.ab1', 'baz.ab1', 'baz.ac1' ) ),
+			array( '{foo,ba{r,z}}.ab1', array( 'foo.ab1', 'bar.ab1', 'baz.ab1' ) ),
+			array( '{foo,ba{r,z}}.{ab1,efg1}', array( 'foo.ab1', 'foo.efg1', 'bar.ab1', 'baz.ab1') ),
+			array( '{foo,bar}.{ab{1,2},efg1}', array( 'foo.ab1', 'foo.ab2', 'foo.efg1', 'bar.ab1', 'bar.ab2' ) ),
+			array( '{foo,ba{r,z}}.{a{b,c}{1,2},efg{1,2}}', array( 'foo.ab1', 'foo.ab2', 'foo.efg1', 'foo.efg2', 'bar.ab1', 'bar.ab2', 'baz.ab1', 'baz.ac1', 'baz.efg2' ) ),
+
+			array( 'no_such_file', array( 'no_such_file' ) ), // Documenting this behaviour here, which is odd (though advertized) - more natural to return an empty array.
+		);
+	}
 }