attributes: skip async spans if level disabled
#1607
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Signed-off-by: Eliza Weisman <[email protected]>
Signed-off-by: Eliza Weisman <[email protected]>
this should hopefully improve the async case a bit as well Signed-off-by: Eliza Weisman <[email protected]>
hawkw
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Oct 1, 2021
## Motivation In #1600, the `instrument` code generation was changed to avoid ever constructing a `Span` struct if the level is explicitly disabled. However, for `async` functions, `#[instrument]` will currently still create the span, but simply skips constructing an `Instrument` future if the level is disabled. ## Solution This branch changes the `#[instrument]` code generation for async blocks to totally skip constructing the span if the level is disabled. I also simplfied the code generation a bit by combining the shared code between the `err` and non-`err` cases, reducing code duplication a bit. Signed-off-by: Eliza Weisman <[email protected]>
hawkw
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Oct 1, 2021
## Motivation In #1600, the `instrument` code generation was changed to avoid ever constructing a `Span` struct if the level is explicitly disabled. However, for `async` functions, `#[instrument]` will currently still create the span, but simply skips constructing an `Instrument` future if the level is disabled. ## Solution This branch changes the `#[instrument]` code generation for async blocks to totally skip constructing the span if the level is disabled. I also simplfied the code generation a bit by combining the shared code between the `err` and non-`err` cases, reducing code duplication a bit. Signed-off-by: Eliza Weisman <[email protected]>
hawkw
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Oct 5, 2021
The changes in #1607 introduced a potential compilation error when using the `#[instrument]` attribute on `async fn`s that return a type that includes a closure or is otherwise unnameable. This is because the future's body code was quoted in two separate places in order to have a separate branch when the span is statically disabled. This means that when a closure is returned, it will technically have two distinct types based on whether or not the span is enabled, since it originates from two separate source code locations (although `quote_spanned!` obscures this, so the compiler diagnostic will appear to have two closures originating from the same location). This branch fixes this issue by changing the code generated for `#[instrument]`ed async functions. Unfortunately, for async functions, we can't have the optimization of not creating the span at all when the level is disabled, because we need to create the span _before_ creating the future, as it may borrow arguments.
hawkw
added a commit
that referenced
this pull request
Oct 5, 2021
## Motivation The changes in #1607 introduced a potential compilation error when using the `#[instrument]` attribute on `async fn`s that return a type that includes a closure or is otherwise unnameable. This is because the future's body code was quoted in two separate places in order to have a separate branch when the span is statically disabled. This means that when a closure is returned, it will technically have two distinct types based on whether or not the span is enabled, since it originates from two separate source code locations (although `quote_spanned!` obscures this, so the compiler diagnostic will appear to have two closures originating from the same location). ## Solution This branch fixes this issue by changing the code generated for `#[instrument]`ed async functions. Unfortunately, for async functions, we can't have the optimization of not creating the span at all when the level is disabled, because we need to create the span _before_ creating the future, as it may borrow arguments. I've also added tests reproducing issue #1615 Fixes #1615
hawkw
added a commit
that referenced
this pull request
Oct 5, 2021
## Motivation The changes in #1607 introduced a potential compilation error when using the `#[instrument]` attribute on `async fn`s that return a type that includes a closure or is otherwise unnameable. This is because the future's body code was quoted in two separate places in order to have a separate branch when the span is statically disabled. This means that when a closure is returned, it will technically have two distinct types based on whether or not the span is enabled, since it originates from two separate source code locations (although `quote_spanned!` obscures this, so the compiler diagnostic will appear to have two closures originating from the same location). ## Solution This branch fixes this issue by changing the code generated for `#[instrument]`ed async functions. Unfortunately, for async functions, we can't have the optimization of not creating the span at all when the level is disabled, because we need to create the span _before_ creating the future, as it may borrow arguments. I've also added tests reproducing issue #1615 Fixes #1615
hawkw
added a commit
that referenced
this pull request
Oct 5, 2021
## Motivation The changes in #1607 introduced a potential compilation error when using the `#[instrument]` attribute on `async fn`s that return a type that includes a closure or is otherwise unnameable. This is because the future's body code was quoted in two separate places in order to have a separate branch when the span is statically disabled. This means that when a closure is returned, it will technically have two distinct types based on whether or not the span is enabled, since it originates from two separate source code locations (although `quote_spanned!` obscures this, so the compiler diagnostic will appear to have two closures originating from the same location). ## Solution This branch fixes this issue by changing the code generated for `#[instrument]`ed async functions. Unfortunately, for async functions, we can't have the optimization of not creating the span at all when the level is disabled, because we need to create the span _before_ creating the future, as it may borrow arguments. I've also added tests reproducing issue #1615 Fixes #1615
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Motivation
In #1600, the
instrumentcode generation was changed to avoid everconstructing a
Spanstruct if the level is explicitly disabled.However, for
asyncfunctions,#[instrument]will currently stillcreate the span, but simply skips constructing an
Instrumentfuture ifthe level is disabled.
Solution
This branch changes the
#[instrument]code generation for async blocksto totally skip constructing the span if the level is disabled. I also
simplfied the code generation a bit by combining the shared code between
the
errand non-errcases, reducing code duplication a bit.