Re-export graphql-tag exports directly, without destructuring.

[benjamn]

Seems to fix #8217, judging from the provided reproduction. Presumably this is because using ECMAScript export...from syntax means we don't have to import anything into the scope of the index.ts module, which makes the whole situation easier for the tree-shaker to reason about.

[brainkim]

lgtm

[cecchi]

FWIW: We're still seeing graphql-tag wind up in our bundle with a Webpack setup and apollo/[email protected]. We precompile all operations, so this is unexpected. I don't have a reproduction repo I can share unfortunately, but am curious whether other Apollo users are running into the same issue still.

Inspecting the Webpack stats shows the reason for the package's inclusion as "harmany side effect" or "harmony import specifier". From a sample build's stats:

        {
          "moduleId": "krkH",
          "moduleIdentifier": "/my-project/node_modules/graphql-tag/lib/index.js 7f8f243dc3479ff2d3a02646936a0fda",
          "module": "../node_modules/graphql-tag/lib/index.js + 14 modules",
          "moduleName": "../node_modules/graphql-tag/lib/index.js + 14 modules",
          "type": "harmony side effect evaluation",
          "userRequest": "./ast.mjs",
          "loc": "3:0-37"
        },
        {
          "moduleId": "krkH",
          "moduleIdentifier": "/my-project/node_modules/graphql-tag/lib/index.js 7f8f243dc3479ff2d3a02646936a0fda",
          "module": "../node_modules/graphql-tag/lib/index.js + 14 modules",
          "moduleName": "../node_modules/graphql-tag/lib/index.js + 14 modules",
          "type": "harmony import specifier",
          "userRequest": "./ast.mjs",
          "loc": "31:31-36"
        }

[nbudin]

I'm seeing the same thing @cecchi is, and in case a reproduction repo is helpful, here's our app that is experiencing this same issue: https://github.com/neinteractiveliterature/larp_library