Pruning not skipped when NPM_CONFIG_PRODUCTION=false

[itaysabato]

From the docs pruning is meant to be skipped when NPM_CONFIG_PRODUCTION=false.

This is not so in my build, e.g. this one from a few minutes ago:

-----> Node.js app detected

-----> Creating runtime environment

       

       NPM_CONFIG_LOGLEVEL=error

       NPM_CONFIG_PRODUCTION=false

       NODE_VERBOSE=false

       NODE_ENV=production

       NODE_MODULES_CACHE=false

-----> Installing binaries

       engines.node (package.json):  8.9.3

       engines.npm (package.json):   5.6.0

       engines.yarn (package.json):  ^1.1.0

       

       Resolving node version 8.9.3...

       Downloading and installing node 8.9.3...

       Bootstrapping npm 5.6.0 (replacing 5.5.1)...

       npm 5.6.0 installed

       Resolving yarn version ^1.1.0...

       Downloading and installing yarn (1.5.1)...

       Installed yarn 1.5.1

-----> Restoring cache

       Skipping cache restore (disabled)

-----> Building dependencies

       Installing node modules (yarn.lock)

       yarn install v1.5.1

       [1/4] Resolving packages...

       [2/4] Fetching packages...

       ...

       [3/4] Linking dependencies...

       ...

       [4/4] Building fresh packages...

       ...

       Done in 279.56s.

-----> Caching build

       Clearing previous node cache

       Skipping cache save (disabled by config)

-----> Pruning devDependencies

       yarn install v1.5.1

       [1/4] Resolving packages...

       [2/4] Fetching packages...

       ...

       [3/4] Linking dependencies...

       ...

       [4/4] Building fresh packages...

       warning Ignored scripts due to flag.

       Done in 24.21s.

-----> Build succeeded!

 !     Unmet dependencies don't fail yarn install but may cause runtime issues

       https://github.com/npm/npm/issues/7494

-----> Discovering process types

       ...

-----> Compressing...

       Done: 99.9M

-----> Launching...

       Released v8

       ... deployed to Heroku

As you can see it adds an unnecessary 24 seconds to the build that I would rather not have.

Thanks.

[jmorrell]

@itaysabato when you are using Yarn, you need to set YARN_PRODUCTION to false or true depending on whether you want devDependencies installed or not.

This process of pruning should be fast, but Yarn has some open issues around this use case:
yarnpkg/yarn#932

More here: #526