Previously this was working for a few use cases by dumb luck, but it
wasn't well tested and became broken by
b29c6bf330. This CL fixes it for real
and adds tests to verify the fix.
Note that there is a change to how we represent an unresolved
import/export: instead of storing a URI_EXISTS modifier in the element
model, we simply mark the imported library element as synthetic.
(This library element existed anyway; we just weren't marking it as
synthetic). This makes it easy to tie in with summaries, since it is
easy for the resynthesizer to detect that the library doesn't exist at
the time the library handle is resolved.
R=brianwilkerson@google.com
Review URL: https://codereview.chromium.org/2235373003 .
Consider libraries `A`, `B`, and `C`, where `C` imports `B`, and `B`
exports `A`. [RESOLVED_UNIT4] of `C` depends on [LIBRARY_ELEMENT4] of
[IMPORTED_LIBRARIES], i.e. `B`. Even though [LIBRARY_ELEMENT4] of `B`
depends on [LIBRARY_ELEMENT3]s of its [EXPORT_SOURCE_CLOSURE] (i.e. `A`
and `B`), [RESOLVED_UNIT4] of `C` sees only [LIBRARY_ELEMENT4] of `B`.
When invalidate results of `B` (but keep results of `C`), we will
invalidate and remove [LIBRARY_ELEMENT4] of `B`, so we lose knowledge
that [RESOLVED_UNIT4] of `C` indirectly depends on `A`.
The solution is do depend on [EXPORT_SOURCE_CLOSURE] of all
[IMPORTED_LIBRARIES] in [RESOLVED_UNIT4] of `C`.
R=brianwilkerson@google.com
BUG=
Review URL: https://codereview.chromium.org/2171673002 .
Konstantin Shcheglov