ajv-peerdep-issue

This repo shows a problem with how npm@5.6.0 hoists dependencies that have peer dependencies.

Running npm install will show the following warning:

npm WARN ajv-keywords@3.1.0 requires a peer of ajv@^6.0.0 but none is installed. You must install peer dependencies yourself.

The following dependencies are relevant:

• this repro itself depends on two packages: ajv@5.5.2 and webpack@3.11.0.
• webpack@3.11.0 depends on ajv@^6.1.0 and ajv-keywords@^3.1.0.
• ajv-keywords@3.1.0 has a peer dependency on ajv@^6.0.0

When npm resolves these dependencies they end up looking like this:

ajv-peerdep-issue@1.0.0 D:\sandbox\ajv-peerdep-issue
`-- ajv@5.5.2
`-- ajv-keywords@3.1.0
`-- webpack@3.11.0
  `-- ajv@6.1.0

This is a problem because the hoisted ajv-keywords@3.1.0 will not have its peer dependency on ajv@^6.0.0 met.