Cannot require from installed gem on Cygwin

[zetetic]

The title may be somewhat misleading. To elaborate, I was unable to install version 2.2.1 from Rubygems on Cygwin. I noticed that there were some fixes in master related to Cygwin, so to experiment I did the following:

1. checked out the master branch locally
2. Appended the path to the Oracle Instant Client folder to PATH
3. gem build ruby-oci8.gemspec
4. gem install ruby-oci8-2.2.1.gem

Step 4 appears to properly build the native extensions and install correctly. However requiring the gem fails:

$ ruby -e 'require "oci8"'

with the message

No such file or directory - <path_to_gems>/gems/ruby-oci8-2.2.1/lib/oci8lib_200.so (LoadError)

but the file 'oci8lib_200.so' is in fact present at the specified location.

I'm at a loss here. Any suggestions?

[kubo]

@zetetic Could you send strace.log created by the following command to kubo@jiubao.org?

$ strace -o strace.log ruby -e 'require "oci8"'

[kubo]

In strace.log:

--- Process 3624 loaded C:\Ruby200\bin\msvcrt-ruby200.dll at 0000000066780000
...
--- Process 3624 loaded C:\Ruby200\lib\ruby\2.0.0\i386-mingw32\enc\encdb.so at 0000000071280000
--- Process 3624 loaded C:\Ruby200\lib\ruby\2.0.0\i386-mingw32\enc\iso_8859_1.so at 0000000070600000
--- Process 3624 loaded C:\Ruby200\lib\ruby\2.0.0\i386-mingw32\enc\trans\transdb.so at 000000006DD40000
--- Process 3624 loaded C:\Ruby200\lib\ruby\2.0.0\i386-mingw32\enc\utf_16le.so at 0000000065480000
--- Process 3624 loaded C:\Ruby200\lib\ruby\2.0.0\i386-mingw32\enc\trans\utf_16_32.so at 000000006D400000

What types of rubies did you install? Did you use mingw32 ruby on cygwin? IMO, you compiled oci8lib_200.so for cygwin ruby. However you used it with mingw32 ruby.

Could you run the following command?

ldd <path_to_gems>/gems/ruby-oci8-2.2.1/lib/oci8lib_200.so 

If the command output includes cygwin1.dll => /usr/bin/cygwin1.dll, it was compiled for cygwin ruby.

[zetetic]

Oops, you're right, that was run with an older Ruby inadvertently. I've sent another log run from the Cygwin ruby.

[kubo]

Could you get strace.log by strace -o strace.log ruby -e "require 'oci8'" instead of strace -o strace.log ruby -e 'require "oci8"' and send me again?

   68   30894 [main] ruby 3756 build_argv: argv[0] = 'C:\cygwin\home\ZBacker\.rbenv\versions\2.0.0-p247\bin\ruby'
   22   30916 [main] ruby 3756 build_argv: argv[1] = '-e'
   22   30938 [main] ruby 3756 build_argv: argv[2] = 'require oci8'
   21   30959 [main] ruby 3756 build_argv: argc 3

The second argument is require oci8. The double quotation marks enclosing oci8 disappeared. IMO, strace dropped double quotation marks inside arguments and you got the following error.

-e:1:in `<main>': undefined local variable or method `oci8' for main:Object (NameError)

[zetetic]

So after several rounds of email I think we finally figured out that this was due to a couple of configuration issues with the Cygwin installation:

• We did not have the Oracle Instant Client files in the PATH, so the gem was unable to load 'oci.dll'
• We did not have the C++ runtime installed, so Oracle Instant Client was unable to load MSVCR100.DLL

We added the Instant Client folder to the path, and installed the Microsoft Visual C++ 2010 Redistributable Package (x64), and now it works.

I confess I'd never seen an error where Ruby failed to load a compiled object file (in this case, oci8lib_200.so). The LoadError message "no such file or directory" is somewhat misleading in this case, since the error is due to a dependency of oci8lib_200.so, not the file itself.

Thanks again to @kubo for some great work digging into this and coming up with an answer.