Remove previous cache from memory after graph creation

[edoardocavazza]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers:

Description

This prevent memory usage to blow up with incremental builds.

fixes #2494

[lukastaegert]

Thanks! We actually had this in Graph.ts until some point:

rollup/src/Graph.ts

Line 87 in fe43b48

delete options.cache; // TODO not deleting it here causes a memory leak; needs further investigation

We have a test for memory leaks that triggered if this did not happen. Not sure why it no longer throws an error.

See #2494 (comment) , would be cool if we could find a working test for this

[lukastaegert]

👍