File::mtime causes errors when file path contains non-english chars

[headius]

From http://jira.codehaus.org/browse/JRUBY-7192

Original Report

Ran into another bug while trying to get rails testsuite running on JRuby. Like, previous one this too is caused by non-english chars.

_Problem_
when [StaticTests#test_served_static_file_with_non_english_filename|https://github.com/rails/rails/blob/master/actionpack/test/dispatch/static_test.rb#L40] is run, it raises the following Exception

Buffer.java:236:in `position': java.lang.IllegalArgumentException
    from CharSequenceParameterConverter.java:125:in `toNative'
    from null:-1:in `__xstat64'
    from LinuxPOSIX.java:116:in `stat'
    from CheckedPOSIX.java:261:in `stat'
    from LazyPOSIX.java:263:in `stat'
    from RubyFileStat.java:160:in `setup'
    from RubyFileStat.java:92:in `newFileStat'
    from Ruby.java:3180:in `newFileStat'
    from RubyFile.java:913:in `mtime'
    from RubyFile$INVOKER$s$1$0$mtime.gen:-1:in `call'
    from CachingCallSite.java:326:in `cacheAndCall'
    from CachingCallSite.java:170:in `call'
    from CallOneArgNode.java:57:in `interpret'
    from FCallOneArgNode.java:36:in `interpret'
    from NewlineNode.java:105:in `interpret'
    from RootNode.java:129:in `interpret'
    from ASTInterpreter.java:121:in `INTERPRET_ROOT'
    from Ruby.java:838:in `runInterpreter'
    from Ruby.java:846:in `runInterpreter'
    from Ruby.java:677:in `runNormally'
    from Ruby.java:522:in `runFromMain'
    from Main.java:395:in `doRunFromMain'
    from Main.java:290:in `internalRun'
    from Main.java:217:in `run'
    from Main.java:197:in `main'

I looked into this further and managed to isolate the issue to this line of [Rack::File|https://github.com/rack/rack/blob/master/lib/rack/file.rb#L67]

last_modified = F.mtime(@path)

With this new information, I was able to reproduce this behaviour directly from command-line

$ jruby -e'puts File.mtime "/home/gaurish/code/repo/rails/actionpack/test/fixtures/public/foo/�ん���.html"'
Buffer.java:236:in `position': java.lang.IllegalArgumentException
....
....

For the intended/expected behaviour it should return DateTime Object as seen below on MRI

$ ruby -e'puts File.mtime "/home/gaurish/code/repo/rails/actionpack/test/fixtures/public/foo/�ん���.html"'
2013-08-03 15:49:14 +0530

Update, if above the chars are not being displayed correctly: the file resides [here|https://github.com/rails/rails/blob/master/actionpack/test/fixtures/public/foo/%E3%81%93%E3%82%93%E3%81%AB%E3%81%A1%E3%81%AF.html]

[headius]

The script in question: https://gist.github.com/headius/e626823606f4451540ff

[kares]

kares@sputnik:~/workspace/oss/jruby$ touch tmp/�ん���.html

kares@sputnik:~/workspace/oss/jruby$ ls tmp/
�ん���.html 

kares@sputnik:~/workspace/oss/jruby$ ruby -e'puts File.mtime "tmp/�ん���.html"'
2018-03-01 16:10:53 +0100

... working like a charm 🎉