Replace manual iterator exhaust with for_each(drop) #48945
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r? @TimNN (rust_highfive has picked a reviewer for you, use r? to override) |
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Re-assigning to @rust-lang/libs: r? @Kimundi
I think that would kind of defeat the purpose of the method proposed here: Not dropping / consuming the iterator seems to be an explicit goal. If consuming the iterator was the goal either |
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Note that |
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And putting it all together with iter.by_ref().for_each(drop);
unsafe { free(self.ptr); }I rather like the looks of what we can already write. |
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Is this operation common enough to warrant a dedicated method in |
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I think I agree that as_ref + for_each sufficiently covers this kind of thing. |
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☔ The latest upstream changes (presumably #47813) made this pull request unmergeable. Please resolve the merge conflicts. |
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(If there is a motion to close I'll open a new PR to replace the instances that I changed to |
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Ping from triage @rust-lang/libs! Can we get a review/decision on this PR? |
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Sorry, seems to have slipped under my radar. I think that I agree with @ExpHP that I personally don't have any strong feelings about wether to add the new method or not, but I know that something like |
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@Kimundi Can we make this a matter of documentation then and include text about |
It feels mure like a "common patterns" document more than the doc comment. Is there a good place for that in one of the books? RBE is on doc.RLO now; maybe there? |
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cc @steveklabnik ^ |
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I've replaced instances of the method with |
| impl<'a, K: 'a, V: 'a> Drop for Drain<'a, K, V> { | ||
| fn drop(&mut self) { | ||
| for _ in self {} | ||
| self.for_each(drop); |
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Ooh, nice that this just works without needing .by_ref() 🙂
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When I saw this comment my immediate thought was to hope that the CI actually passed, because I was pretty sure it would work but not 100%. :p
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Ping from triage @Kimundi! If I understood correctly this PR still needs your review. |
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Ping from triage! Can @Kimundi (or someone else from @rust-lang/libs) review this? |
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@bors r+ |
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📌 Commit 5c58eec has been approved by |
Replace manual iterator exhaust with for_each(drop)
This originally added a dedicated method, `Iterator::exhaust`, and has since been replaced with `for_each(drop)`, which is more idiomatic.
<del>This is just shorthand for `for _ in &mut self {}` or `while let Some(_) = self.next() {}`. This states the intent a lot more clearly than the identical code: run the iterator to completion.
<del>At least personally, my eyes tend to gloss over `for _ in &mut self {}` without fully paying attention to what it does; having a `Drop` implementation akin to:
<del>`for _ in &mut self {}; unsafe { free(self.ptr); }`</del>
<del>Is not as clear as:
<del>`self.exhaust(); unsafe { free(self.ptr); }`
<del>Additionally, I've seen debate over whether `while let Some(_) = self.next() {}` or `for _ in &mut self {}` is more clear, whereas `self.exhaust()` is clearer than both.
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☀️ Test successful - status-appveyor, status-travis |
This originally added a dedicated method,
Iterator::exhaust, and has since been replaced withfor_each(drop), which is more idiomatic.This is just shorthand forfor _ in &mut self {}orwhile let Some(_) = self.next() {}. This states the intent a lot more clearly than the identical code: run the iterator to completion.At least personally, my eyes tend to gloss overfor _ in &mut self {}without fully paying attention to what it does; having aDropimplementation akin to:for _ in &mut self {}; unsafe { free(self.ptr); }Is not as clear as:self.exhaust(); unsafe { free(self.ptr); }Additionally, I've seen debate over whetherwhile let Some(_) = self.next() {}orfor _ in &mut self {}is more clear, whereasself.exhaust()is clearer than both.