Exit status of wa-compile not properly propagating

[aYuMatsuzawa]

• OS: macOS sierra 10.12.6
• package version: 0.11.0
• executing command: wa compile -Oo output/dir/target.wasm source.c
• output:

$ npm run wasm # wa compile -Oo priv/static/dist/fib.wasm fib.c

> [email protected] wasm /Users/yumatsuzawa/Workspace/yubot
> wa compile -Oo priv/static/dist/fib.wasm wasm/src/fib.c

Compiling on darwin-x64 ...

clang wasm/src/fib.c
 -O
 -c
 --target=wasm32-unknown-unknown
 -emit-llvm
 -nostdinc
 -nostdlib
 -D WEBASSEMBLY
 -isystem /Users/yumatsuzawa/Workspace/yubot/node_modules/webassembly/include
 -o /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa1_92739CYGeomA1qYDj.tmp

llvm-link /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa1_92739CYGeomA1qYDj.tmp /Users/yumatsuzawa/Workspace/yubot/node_modules/webassembly/lib/webassembly.bc
 -only-needed
 -o /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa2_92739T8s4xIqm7bBx.tmp

llc /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa2_92739T8s4xIqm7bBx.tmp
 -march=wasm32
 -filetype=asm
 -asm-verbose=false
 -thread-model=single
 -data-sections
 -function-sections
 -o /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa1_92739CYGeomA1qYDj.tmp

s2wasm /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa1_92739CYGeomA1qYDj.tmp
 --import-memory
 --allocate-stack 10000
 -o /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa2_92739T8s4xIqm7bBx.tmp

wasm-opt /var/folders/f0/03jcty091k3684vmw5qr8yf00000gp/T/wa2_92739T8s4xIqm7bBx.tmp
 -O3
 --coalesce-locals-learning
 --dce
 --duplicate-function-elimination
 --inlining
 --local-cse
 --merge-blocks
 --optimize-instructions
 --reorder-functions
 --reorder-locals
 --vacuum
 -o priv/static/dist/fib.wasm

Failed opening 'priv/static/dist/fib.wasm'
FAILED Error: code 1
    at ChildProcess.<anonymous> (/Users/yumatsuzawa/Workspace/yubot/node_modules/webassembly/cli/util.js:38:24)
    at emitTwo (events.js:126:13)
    at ChildProcess.emit (events.js:214:7)
    at maybeClose (internal/child_process.js:925:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:209:5)

$ echo $status
0

In this case, priv/static/dist directory does not exist yet, so wasm-opt failing on file opening.
It exited with error code 1, though wa compile command itself is exiting with exit status 0 as shown above (I'm using fish-shell so echo $status equals to echo $? in bash).