composer doesn't use tabs

.gitattributes

@@ -3,6 +3,6 @@
 
 # These files are always considered text and should use LF.
 # See core.whitespace @ http://git-scm.com/docs/git-config for whitespace flags.
-*.php   text eol=lf whitespace=blank-at-eol,-blank-at-eof,space-before-tab,tabwidth=4 diff=php
-*.json  text eol=lf whitespace=blank-at-eol,-blank-at-eof,space-before-tab,tabwidth=4
-*.test  text eol=lf whitespace=blank-at-eol,-blank-at-eof,space-before-tab,tabwidth=4
+*.php   text eol=lf whitespace=blank-at-eol,-blank-at-eof,space-before-tab,tab-in-indent,tabwidth=4 diff=php
+*.json  text eol=lf whitespace=blank-at-eol,-blank-at-eof,space-before-tab,tab-in-indent,tabwidth=4
+*.test  text eol=lf whitespace=blank-at-eol,-blank-at-eof,space-before-tab,tab-in-indent,tabwidth=4