How do you verify npm is compiled against iojs

[Raynos]

cc @rvagg @othiym23

TL:DR;

• How do I determine which version of iojs my npm binary is compiled against
• How do I determine whether binary modules fail because they dont support iojs or I compiled them against node instead of iojs

I compiled iojs from source. This created a iojs compatible binary at /usr/local/bin/npm version

I try to verify that my new npm is compiled against iojs with

raynos at raynos-MacBookPro  ~/projects
$ /usr/local/bin/npm version
{ npm: '2.2.0',
  ares: '1.9.0-DEV',
  http_parser: '1.0',
  modules: '11',
  node: '0.10.26',
  openssl: '1.0.1e',
  uv: '0.10.25',
  v8: '3.14.5.9',
  zlib: '1.2.3' }
raynos at raynos-MacBookPro  ~/projects
$ npm version
{ http_parser: '1.0',
  node: '0.10.26',
  v8: '3.14.5.9',
  ares: '1.9.0-DEV',
  uv: '0.10.25',
  zlib: '1.2.3',
  modules: '11',
  openssl: '1.0.1e',
  npm: '1.4.28' }

As you can see the only difference is the version of npm, I know my local npm on PATH is compiled against node 0.10

How do I know whether npm install or npm rebuild in my application will actually recompile my modules against iojs.

There is nothing in the npm rebuild output that tells me information

> [email protected] install /home/raynos/uber/demand-io/node_modules/playdoh-perf/node_modules/v8-profiler
> node-pre-gyp install --fallback-to-build

[v8-profiler] Success: "/home/raynos/uber/demand-io/node_modules/playdoh-perf/node_modules/v8-profiler/build/profiler/v5.2.2/node-v11-linux-x64/profiler.node" already installed
Pass --build-from-source to recompile

> [email protected] install /home/raynos/uber/demand-io/node_modules/ringpop-sirvice/node_modules/ringpop/node_modules/farmhash
> node-gyp rebuild

make: Entering directory `/home/raynos/uber/demand-io/node_modules/ringpop-sirvice/node_modules/ringpop/node_modules/farmhash/build'
  CXX(target) Release/obj.target/farmhash/src/upstream/farmhash.o
  CXX(target) Release/obj.target/farmhash/src/farmhash.o
  SOLINK_MODULE(target) Release/obj.target/farmhash.node
  SOLINK_MODULE(target) Release/obj.target/farmhash.node: Finished
  COPY Release/farmhash.node
make: Leaving directory `/home/raynos/uber/demand-io/node_modules/ringpop-sirvice/node_modules/ringpop/node_modules/farmhash/build'

When I run my application it fails. I presume its because v8-profiler doesnt support iojs but I cant tell from the output

$ iojs server/server.js 
module.js:324
    throw err;
          ^
Error: Cannot find module '/home/raynos/uber/demand-io/node_modules/playdoh-perf/node_modules/v8-profiler/build/profiler/v5.2.2/node-v42-linux-x64/profiler.node'
    at Function.Module._resolveFilename (module.js:322:15)
    at Function.Module._load (module.js:264:25)
    at Module.require (module.js:351:17)
    at require (module.js:370:17)
    at Object.<anonymous> (/home/raynos/uber/demand-io/node_modules/playdoh-perf/node_modules/v8-profiler/v8-profiler.js:4:15)
    at Module._compile (module.js:446:26)
    at Object.Module._extensions..js (module.js:464:10)
    at Module.load (module.js:341:32)
    at Function.Module._load (module.js:296:12)
    at Module.require (module.js:351:17)

It'd be great if we had a way of knowing what the state of my binary dependencies are. i.e. which version of v8 are they compiled against. Which version of node.h or iojs.h

[mscdex]

Currently the process.versions.node should be updated. So it should show 1.0.0 or 1.0.1.

[Raynos]

@mscdex that's only for the iojs binary. I want to figure out how to use the npm binary in some fashion to figure out whether its linked againts node 0.10 or iojs 1.0.2

[othiym23]

There's definitely nothing specific that npm itself does. Remember that it doesn't even build the binaries, but instead hands that responsibility off to node-gyp during the package build / rebuild step. If you want to futz around with nm / ldd / otool, you can probably figure out which libraries were used to build a given binary, but a more explicit denotation would certainly be handy. Maybe open an issue on node-gyp, or see if any of the discussion on nodejs/node-gyp#564 gives you any ideas.

[Fishrock123]

seems like a node-gyp thing? re-open if it isn't. :)