Add a test for property access on ~Escapable types#1155
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natecook1000 wants to merge 61 commits intoswiftlang:jgrynspan/162-redesign-value-capturefrom
Open
Add a test for property access on ~Escapable types#1155natecook1000 wants to merge 61 commits intoswiftlang:jgrynspan/162-redesign-value-capturefrom
natecook1000 wants to merge 61 commits intoswiftlang:jgrynspan/162-redesign-value-capturefrom
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This PR completely rewrites how we capture expectation conditions. For example, given the following expectation: ```swift ``` We currently detect that there is a binary operation and emit code that calls the binary operator as a closure and passes the left-hand value and right-hand value, then checks that the result of the operation is `true`. This is sufficient for simpler expressions like that one, but more complex ones (including any that involve `try` or `await` keywords) cannot be expanded correctly. With this PR, such expressions _can_ generally be expanded correctly. The change involves rewriting the macro condition as a closure to which is passed a local, mutable "context" value. Subexpressions of the condition expression are then rewritten by walking the syntax tree of the expression (using typical swift-syntax API) and replacing them with calls into the context value that pass in the value and related state. If the expectation ultimately fails, the collected data is transformed into an instance of the SPI type `Expression` that contains the source code of the expression and interesting subexpressions as well as the runtime values of those subexpressions. Nodes in the syntax tree are identified by a unique ID which is composed of the swift-syntax ID for that node as well as all its parent nodes in a compact bitmask format. These IDs can be transformed into graph/trie key paths when expression/subexpression relationships need to be reconstructed on failure, meaning that a single rewritten node doesn't otherwise need to know its "place" in the overall expression. There remain a few caveats (that also generally affect the current implementation): - Mutating member functions are syntactically indistinguishable from non-mutating ones and miscompile when rewritten; - Expressions involving move-only types are also indistinguishable, but need lifetime management to be rewritten correctly; and - Expressions where the `try` or `await` keyword is _outside_ the `#expect` macro cannot be expanded correctly because the macro cannot see those keywords during expansion. The first issue might be resolvable in the future using pointer tricks, although I don't hold a lot of hope for it. The second issue is probably resolved by non-escaping types. The third issue is an area of active exploration for us and the macros/swift-syntax team.
This tests using a ~Escapable type as the LHS of a property access inside the `#expect` and `#require` macros. A ~Escapable return value from `#require` is unsupported.
natecook1000
requested review from
briancroom,
grynspan,
stmontgomery and
suzannaratcliff
as code owners
Contributor
|
@swift-ci please test |
stmontgomery
added
enhancement
Contributor
|
I believe this test is dependent on #840, right? |
Member
Author
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Right! I believe it's aimed at that branch, not main. Should I direct it somewhere else? |
Contributor
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Nope, just confirming the dependency is why the test failed. You could redirect the PR to merge to that branch, and then it would pass? |
Contributor
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@swift-ci test |
…(still not ~Copyable though)
…nonescapable-test
…cript to allow yielding return of values" This reverts commit f920afe.
…nonescapable-test
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This tests using a ~Escapable type as the LHS of a property access inside the
#expectand#requiremacros. A ~Escapable return value from#requireis unsupported.Checklist: