yarn --flat sees a version conflict where there is none

[mxmul]

Do you want to request a feature or report a bug?
bug

What is the current behavior?
yarn --flat sees a version conflict where there is none (in >=0.27.0).

If I have package A that requires 'left-pad@>=1.0.1" and package B that requires both A and "[email protected]", and install package B with yarn --flat there is a conflict.

If the current behavior is a bug, please provide the steps to reproduce.
https://github.com/mxmul/yarn_flat_regression

What is the expected behavior?
yarn would choose the one version that satisfies the version constraints (1.1.1)

Please mention your node.js, yarn and operating system version.
[email protected] [email protected] [email protected]

[bestander]

Related to #3778 and yarnpkg/rfcs#68

[aij]

Yarn can see a conflict even when both dependencies resolve to the same version number:

info Unable to find a suitable version for "history", please choose one by typing one of the numbers below:
  1) "history@^3.0.0" which resolved to "3.3.0"
  2) "history@ccap/history#3.3.0-ccap1" which resolved to "3.3.0"
Answer?: 

Of course the code is actually different depending on whether it is fetched from NPM or from Gitlab.

In our case, NPM will happily use the Gitlab version to satisfy both dependencies. Should Yarn do the same?

Admittedly, this is a hacky way to get NPM to use our patched version of history within an unpatched react-router. The new resolutions feature in Yarn seems like a cleaner way to accomplish the same, albeit incompatible with NPM.

[aij]

Ugh, that's actually worse than I realized. Even though it's prompting, the answer is effectively ignored in my above example, since the call to reporter.select returns just the string 3.3.0 in either case.