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Import more top level declarations #164
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adamiak
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Mar 25, 2024
Consider three files:
- file A
- file B
- file C
The structure is the following:
- file A does an import that looks like this `import { Decl, IDecl }`
from file B.
- file B declares the `Decl` object and does an import that looks like
`import { IDecl }` from file C.
- file C declares the `IDecl` object.
Now the flow of what happened:
- the code sees that there is an import in file A so it calls
`resolveFileImport()`.
- that function sees that it will import only two things from file B.
- it processes the first object (`Decl`), it finds it in the
declarations of file B. It adds it to the `alreadyImportedObjects`
map.
- it processes the second object (`IDecl`), it does not find it in the
declarations of file B. It calls itself recursively to resove all the
imports of file B. IMPORTANT: it passes the `alreadyImportedObjects` as
an argument to that call. That call **will** modify that object, filling
it up with all the imports that file B does. When it finds the `IDecl`
object from the imports that are happening what we want to have happened
is to only include that `IDecl` object in the `alreadyImportedObjects`
map. But that map becomes tainted. The solution to that problem is to do
a deep copy of that object so any tainting is contained to that copy
that is later dropped.
A note on performance. Copying is almost always not the thing we want to
do if we want to achieve high performance. But in this case this
solution is fine because this is a statistically rare case.
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Apr 24, 2024
* Import more top level declarations
* Compact stuff
* Tests
* Fix a very rare edge case in the PolygonZKEVM fix
Consider three files:
- file A
- file B
- file C
The structure is the following:
- file A does an import that looks like this `import { Decl, IDecl }`
from file B.
- file B declares the `Decl` object and does an import that looks like
`import { IDecl }` from file C.
- file C declares the `IDecl` object.
Now the flow of what happened:
- the code sees that there is an import in file A so it calls
`resolveFileImport()`.
- that function sees that it will import only two things from file B.
- it processes the first object (`Decl`), it finds it in the
declarations of file B. It adds it to the `alreadyImportedObjects`
map.
- it processes the second object (`IDecl`), it does not find it in the
declarations of file B. It calls itself recursively to resove all the
imports of file B. IMPORTANT: it passes the `alreadyImportedObjects` as
an argument to that call. That call **will** modify that object, filling
it up with all the imports that file B does. When it finds the `IDecl`
object from the imports that are happening what we want to have happened
is to only include that `IDecl` object in the `alreadyImportedObjects`
map. But that map becomes tainted. The solution to that problem is to do
a deep copy of that object so any tainting is contained to that copy
that is later dropped.
A note on performance. Copying is almost always not the thing we want to
do if we want to achieve high performance. But in this case this
solution is fine because this is a statistically rare case.
* Changeset
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Resolves L2B-4024 L2B-4023