--prefix is broken in 0.1 distribution (rpath related)

[thoughtpolice]

In an attempt to make a Homebrew formula for the 0.1 release, I noticed that --prefix seems somewhat broken.

Here's the output from brew install rust on my branch:

$ brew install rust
==> Downloading http://dl.rust-lang.org/dist/rust-0.1.tar.gz
File already downloaded in /Users/a/Library/Caches/Homebrew
==> ./configure --prefix=/usr/local/Cellar/rust/0.1
==> make
==> make install
$ /usr/local/Cellar/rust/0.1: 18 files, 32M, built in 11.4 minutes

So it just does ./configure --prefix=...; make; make install like the recommended installation instructions. Homebrew works by just installing into a special prefix for every formula, and then symlinking all the resulting binaries into /usr/local or where-ever brew is installed (as you can see above):

$ which rustc
/usr/local/bin/rustc
$ readlink `which rustc`
../Cellar/rust/0.1/bin/rustc

When run, rustc spits out:

$ rustc
dyld: Library not loaded: @loader_path/@rpath/librustrt.dylib
  Referenced from: /usr/local/Cellar/rust/0.1/bin/../lib/libcore-14bd852465126fe7-0.1.dylib
  Reason: image not found
[1]    92198 trace trap  rustc

So it seems to be something rpath related.

[brson]

I wonder if this is related to the way homebrew does the install (like maybe the symlink screws up our rpath calculations). Does --prefix work for you when installing manually?

[thoughtpolice]

It's possible but I don't think so, as the same error occurs from just running the real rustc executable manually:

$ /usr/local/Cellar/rust/0.1/bin/rustc
dyld: Library not loaded: @loader_path/@rpath/librustrt.dylib
  Referenced from: /usr/local/Cellar/rust/0.1/bin/../lib/libcore-14bd852465126fe7-0.1.dylib
  Reason: image not found
[1]    18945 trace trap  RUST_LOG=rustc::back::rpath /usr/local/Cellar/rust/0.1/bin/rustc

So this is really bailing at dyld attempting to resolve dynamic libraries when the executable is loaded. I'll try --prefixing somewhere else with a custom build in a moment.

[thoughtpolice]

Apparently someone has gotten a Rust formula into Homebrew sometime in the past day. I'll build it but I'm fairly certain I'll see the same thing.

I'm still tracking this issue down a bit, I'll report more details soon and hopefully hop on IRC to discuss.

[thoughtpolice]

Update: I noticed something similar with other formulae in Homebrew (notably radare2) and I got the rust compiler working by saying:

$ DYLD_LIBRARY_PATH=/usr/local/lib rustc

Which correctly confronts me with the compiler options etc. I do not exactly know why this is the case, or why it has mysteriously broken it seems (I've installed plenty of things that work,) but because I can reproduce and fix this with other formulae, I'm closing this ticket unless someone disagrees.

I guess I need to just add this to my .zshrc or something. Hopefully it doesn't kill me later.

[brson]

It still shouldn't be requiring an explicit DYLD_LIBRARY_PATH. Are you by chance using an older version of OS X? Reopening if you don't mind.

[brson]

FWIW. I know that OS X pre-10.5 will not work correctly, and I haven't heard of anybody using 10.5.

[thoughtpolice]

Yes, thinking upon it more (it was late last night) it should probably stay open - considering I can run the Rust compiler easily from any other installed prefix, I'm still wondering what exactly is going wrong.

And no, I'm not running 10.5, I'm running Snow Leopard (10.6.8.)

[thoughtpolice]

Actually, I think I figured this out.

My .zshrc had already accidentally over-written DYLD_FALLBACK_LIBRARY_PATH (because WINE wanted it that way, and I don't have it anymore anyway.) From dyld(1):

DYLD_FALLBACK_LIBRARY_PATH
          This is a colon separated list of directories that contain  libraries.   It  is  used  as  the
          default  location  for  libraries  not  found in their install path.  By default, it is set to
          $(HOME)/lib:/usr/local/lib:/lib:/usr/lib.

I had unilaterally overwritten it to not contain /usr/local/lib, and instead some other crap for WINE. Since resetting this, several of my homebrew formulae have started working - they failed in the first place because they didn't contain a full rpath pointing to /usr/local/lib; they only referenced stuff like libr_util.dylib in the case of radare2. This would normally work with a default DYLD_FALLBACK_LIBRARY_PATH, since dyld will search /usr/local/lib after it doesn't find them elsewhere.

I am re-brewing the Homebrew rust formula and will follow up shortly. Should it work, I will close this issue as it was simply my messed up environment.

[thoughtpolice]

Huzzah! Un-breaking DYLD_FALLBACK_LIBRARY_PATH results in success:

$ brew install rust
==> Downloading http://dl.rust-lang.org/dist/rust-0.1.tar.gz
File already downloaded in /Users/a/Library/Caches/Homebrew
==> ./configure --prefix=/usr/local/Cellar/rust/0.1
==> make
==> make install
/usr/local/Cellar/rust/0.1: 18 files, 32M, built in 12.4 minutes
$ brew test rust
Testing rust
==> /usr/local/Cellar/rust/0.1/bin/rustc
==> /usr/local/Cellar/rust/0.1/bin/rustdoc
==> /usr/local/Cellar/rust/0.1/bin/cargo
$ 

And:

$ rustc
usage: rustc [options] <input>

options:

    -h --help          display this message
    -v --version       print version info and exit

    -o <filename>      write output to <filename>
    --out-dir <dir>    write output to compiler-chosen filename in <dir>
    --lib              compile a library crate
    --bin              compile an executable crate (default)
    --static           use or produce static libraries
    --no-core          omit the 'core' library (used and imported by default)
    --pretty [type]    pretty-print the input instead of compiling
    --ls               list the symbols defined by a crate file
    -L <path>          add a directory to the library search path
    --no-verify        suppress LLVM verification step (slight speedup)
    --parse-only       parse only; do not compile, assemble, or link
    --no-trans         run all passes except translation; no output
    -g                 produce debug info
    --opt-level <lvl>  optimize with possible levels 0-3
    -O                 equivalent to --opt-level=2
    -S                 compile only; do not assemble or link
    --no-asm-comments  do not add comments into the assembly source
    -c                 compile and assemble, but do not link
    --emit-llvm        produce an LLVM bitcode file
    --save-temps       write intermediate files in addition to normal output
    --stats            gather and report various compilation statistics
    --cfg <cfgspec>    configure the compilation environment
    --time-passes      time the individual phases of the compiler
    --time-llvm-passes time the individual phases of the LLVM backend
    --sysroot <path>   override the system root
    --target <triple>  target to compile for (default: host triple)
    --test             build test harness
    --gc               garbage collect shared data (experimental/temporary)
    --warn-unused-imports
                       warn about unnecessary imports
    --no-lint-ctypes   suppress lint-style ctypes usage check

Closing this ticket, mystery solved.