PipesLibrary

This project was generated with Angular CLI version 7.3.0.

About the project

This project contains:

1. An apps folder with an example-app using all de libraries.
2. A libs folder containing 3 basic libraries.
   • icons: Component library that renders a smiley.
   • uppercasePipe: Pipe library that transform the text to uppercase.
   • complexComponents: Component library that uses icons and uppercasePipe. The errors occurs when compiling this library when uppercasePipe is using yarn workspaces (symlink).
3. Yarn workspaces in package.json
   • "dist/libs/*"

Build folders are dist/{apps|libs}/{name}

How to reproduce the yarn workspaces error

1. Clone this project
2. Install dependencies. yarn install
   • If you build the project now, it will use npm libraries and will work. yarn build example-app
   • If you build the libraries now, it will use npm libraries and will work. yarn build:libs
3. Build the libraries yarn build:libs
4. Use yarn workspaces. This will create a symlink from node_modules folder to our libraries dist folder. yarn install
   • node_modules/@example-lib/icons will link to dist/libs/icons
   • node_modules/@example-lib/uppercase-pipe will link to dist/libs/uppercase-pipe
   • node_modules/@example-lib/complex-components will link to dist/libs/complex-components
5. Build the libraries yarn build:libs. This will throw Cannot read property 'type' of null

About the error

The errors throws when compiling one library that contains a pipe from another library placed in yarn workspace. There are no errors if the other library is different than pipe (component, directive, etc).

I guess the error is related with getting summary from summaryCache, because sometimes it looks for node_modules/@example-lib/uppercase-pipe and other for dist/libs/uppercase-pipe.

In file compiler line 657:

const pipes = ngModule.transitiveModule.pipes.map(
    pipe => this._metadataResolver.getPipeSummary(pipe.reference));

The map function returns null.

In file template_parser line 138:

const uniqPipes = removeSummaryDuplicates(pipes);

crashes because the pipe is null.

Workaround

To avoid this error you have to deploy the libraries containing pipes before build the libraries and exclude this libraries from yarn workspaces, which is annoying when developing libraries.

Logs

I've committed logs files that I've used to try to figure out why the error happens. I've just console.trace in _loadSummary function in compiler.umd.js file:

        CompileMetadataResolver.prototype._loadSummary = function (type, kind) {
            var typeSummary = this._summaryCache.get(type);
            console.trace('GETTING _loadSummary', type, typeSummary)
            if (!typeSummary) {
                var summary = this._summaryResolver.resolveSummary(type);
                typeSummary = summary ? summary.type : null;
                this._summaryCache.set(type, typeSummary || null);
              console.trace('SETTING _loadSummary', type, typeSummary)
            }
            return typeSummary && typeSummary.summaryKind === kind ? typeSummary : null;
        };