Error: Cannot find module 'bower'

[Turbo87]

#157 appears to have broken CI for ember-cli-shims (see https://travis-ci.org/ember-cli/ember-cli-shims/jobs/300982718) and I assume probably for other addons too.

ember-cli-shims is running CI once per day, yesterday it worked and today it is broken with this error:

Error: Cannot find module 'bower' from '/home/travis/build/ember-cli/ember-cli-shims/node_modules/ember-cli/bin'
    at /home/travis/build/ember-cli/ember-cli-shims/node_modules/resolve/lib/async.js:48:31
    at processDirs (/home/travis/build/ember-cli/ember-cli-shims/node_modules/resolve/lib/async.js:182:39)
    at ondir (/home/travis/build/ember-cli/ember-cli-shims/node_modules/resolve/lib/async.js:197:13)
    at load (/home/travis/build/ember-cli/ember-cli-shims/node_modules/resolve/lib/async.js:80:43)
    at onex (/home/travis/build/ember-cli/ember-cli-shims/node_modules/resolve/lib/async.js:105:17)
    at /home/travis/build/ember-cli/ember-cli-shims/node_modules/resolve/lib/async.js:26:73
    at FSReqWrap.oncomplete (fs.js:123:15)

/cc @kategengler @hjdivad @rwjblue @twokul

[Turbo87]

ember-cli-mocha has the same issue: https://travis-ci.org/ember-cli/ember-cli-mocha/jobs/301308777

[Turbo87]

It appears that all scenarios are affected that don't use Bower at all because they rely on ember-source. That means ember-default for most cases and ember-lts-2.12/2.16.

[rwjblue]

Ugh. Thanks for reporting.

Why are we still attempting to resolve bower when it isn’t used for the scenario?

[rwjblue]

I have a repro, working on a solution now.

[Emrvb]

@rwjblue

There are two reasons for that:

1. Dependency manager adapters are loaded for a task based on all scenarios. So if one scenario uses bower, the adapter is loaded and used for every scenario that will be run.
2. The bower dependency manager never skips because _getDependencySetAccountingForDeprecatedTopLevelKeys will always make the adapter assume there are dependencies to install.

I've been working on patch as well. Want a diff?

[rwjblue]

@Emrvb:

Dependency manager adapters are loaded for a task based on all scenarios. So if one scenario uses bower, the adapter is loaded and used for every scenario that will be run.

This would only affect the ember try:each scenario, and should essentially still work properly as far as I can tell?

The bower dependency manager never skips because _getDependencySetAccountingForDeprecatedTopLevelKeys will always make the adapter assume there are dependencies to install.

Right, this is the real issue IMHO. We need to tweak changeToDependencySet something like:

    depSet = this._getDependencySetAccountingForDeprecatedTopLevelKeys(depSet);
    var needsInstall = depSet && Object.keys(depSet.dependencies).length + Object.keys(depSet.devDependencies).length > 0;
    if (!needsInstall) { 
      return RSVP.resolve([]); 
    }

[Emrvb]

@rwjblue

This would only affect the ember try:each scenario, and should essentially still work properly as far as I can tell?

Not exactly, the try:one command depends on the try-each-test task, which will always load all scenarios.

Right, this is the real issue IMHO. We need to tweak changeToDependencySet something like:

Since the problem is caused by _getDependencySetAccountingForDeprecatedTopLevelKeys I thought of fixing it like this:

_getDependencySetAccountingForDeprecatedTopLevelKeys: function(depSet) {
    if (depSet[this.configKey]) {
      return depSet[this.configKey];
    } else if ('dependencies' in depSet || 'devDependencies' in depSet || 'resolutions' in depSet) {
      return { dependencies: depSet.dependencies, devDependencies: depSet.devDependencies, resolutions: depSet.resolutions };
    }
    return null;
  },

[hjdivad]

Summarizing discussion + fix WIP with @rwjblue

• load bower adapter all the time
• bower adapter learn to no-op if it has no dependencies to install
• add implicit bower dependency for legacy top-level dependencies and devDependencies
• add implicit bower dependency if there exists a bower.json
• do not run bower install during cleanup if we no-op because we had no dependencies to install

[kategengler]

add implicit bower dependency if there exists a bower.json

Why would we want to add a bower dep even when there are not any bower scenarios?

[hjdivad]

Why would we want to add a bower dep even when there are not any bower scenarios?

In typing out a reply, I realize that I was wrong on this point.

---

The case we want to deal with is

There are bower dependencies in scenario A, but not in scenario B.

We were running into problems cleaning up in B, but we should just no-op in that case. We'll still be able to clean up in A because bower will have been installed, since there were bower dependencies.