Typescript build not working as expected with symlinks.

[micah-williamson]

TypeScript Version: 2.0.0-dev.20160630

Code

When I use a symlink in Windows I'm getting different build results. I haven't tested this with Mac/Linux yet.

dev
  app
    node_modules
      test
        foo.ts
    index.ts

Builds to:

dev
  app
    bld
      node_modules
        test
          foo.js
      index.js
    ...

Using symlink

mklink /D "c:\dev\app\node_modules\test\" "c:\dev\test\"

dev
  test
    foo.ts
  app
    node_modules
      test => /dev/test
    index.ts

Builds to:

dev
  app
    bld
      app   
        index.js
      test
        foo.js
    ...

Expected behavior:

Building with and without a symlink should build the same.

Actual behavior:

Building without a symlink behaves normally. Building with a symlink does not treat the directory as a link but uses the actual location of the linked directory. This causes problems with module resolution.

[micah-williamson]

This appears to be a problem on Mac/Linux. Symlinked node_modules do not build the same way installed node_modules do. This was not a problem in ts 1.8.x.

This comes up for me because I am working on three libraries where two depend on the other. So I have library A, that B and C depend on. For development harmony, I use symlinks to work on them all at the same time.

The alternatives would be-

1. To regularly push a changes to library A for B to npm update
2. To regularly copy the contents of A to B/node_modules/A and C/node_modules/A
3. To clone A to B/node_modules/A and regularly copy it's contents to C/node_modules/A (or vice versa)

So i'd much prefer symlinks if possible.

[opsxcq]

+1

[mhegazy]

The problem here is that the compiler will follow an import to test then resolve its realpath (a change made in TS 2.0 to support npm link scenarios) to /dev/test/foo.ts, and thus your program really has two files, /dev/app/index.ts and /dev/test/foo.ts, and there is no way to tell the compiler not to build /dev/test/foo.ts, as all source files (i.e. .ts files) are required to generate output.

An alternative is to use intermediate .d.ts files for your projects. i.e. have /dev/test/foo.d.ts instead of /dev/test/foo.ts. .d.ts files do not generate outputs, and will not participate in building your output folder structure. this means that when building your /dev/test you need to generate a declaration file (i.e. use --declaration).

Ultimately the fix would be the compiler to understand symlinks for all files, and unify files that come from the same real path. this is not a simple change, and would require some major changes to how programs are created and used.

[asibross]

I am experiencing the same issue. Looking forward to a fix.