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Implement DebugStruct::non_exhaustive. - #66716
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rust-highfive
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Nov 24, 2019
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r? @kennytm (rust_highfive has picked a reviewer for you, use r? to override) |
richard-uk1
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Nov 24, 2019
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r? @scottmcm since they saw the internals post. |
CAD97
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Nov 24, 2019
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I'd add a field foo to this structure, just for clarity's sake.
Probably Box<dyn (pick your favorite object safe trait that isn't `Debug`)>.
CAD97
commented
Nov 24, 2019
Contributor
Would it be simpler to print e.g. smth like pubfnnon_exhaustive(&mutself) -> &mutDebugStruct<'a,'b>{self.result = self.result.and_then(|_| {ifself.is_pretty(){if !self.has_fields{self.fmt.write_str(" {\n")?;}letmut slot = None;letmut state = Default::default();letmut writer = PadAdapter::wrap(&mutself.fmt,&mut slot,&mut state);
writer.write_str("..\n")}else{let prefix = ifself.has_fields{", "}else{" { "};self.fmt.write_str(prefix)?;self.fmt.write_str("..")}});self.has_fields = true;self}pubfnfinish_non_exhaustive(&mutself) -> fmt::Result{self.non_exhaustive().finish()} |
richard-uk1
commented
Nov 24, 2019
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That is certainly another possibility, I'd be interested to hear other people's opinions. |
CAD97
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Nov 24, 2019
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🚩🚩🚩🚩🚩🚩
You do not want to use .into_iter().copied() here. This takes an autoref to &[_] and will break when we eventually add impl IntoIterator for [_]. Use .iter() instead.
JohnCSimon
commented
Nov 30, 2019
Ping from triage: @scottmcm - all checks pass, can you please review this PR? |
JohnCSimon
commented
Dec 7, 2019
Pinging again from triage: |
Dylan-DPC-zz
commented
Dec 10, 2019
r? @dtolnay |
dtolnay
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Dec 15, 2019
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Thanks! I would be on board with supporting .. in DebugStruct.
I think opaque_field should be removed from this PR. It is easy enough to get the same behavior with
field("field", &format_args!("_")). But the representationStruct { field: _ }is not one that I find intuitive or would want to encourage. Almost anything would be better, for examplefield("field", &format_args!("<some Iterator>")). I would prefer to leave this up to the caller rather than dictating a default representation for opaque fields. This way the caller can write an impl that is as useful as possible within their constraints.The bool argument of non_exhaustive doesn't seem useful. The caller would pretty much always need to pass true which is just noisy. In the rare case that a struct may or may not print as nonexhaustive depending on a runtime decision, the Debug impl can use an
ifaround the non_exhaustive call.I would lean toward making this an alternative to
finishto sidestep the ambiguity about what it should do if you print more fields after calling non_exhaustive.f.debug_struct("Struct").field("field", &self.field).finish_non_exhaustive()
rust-highfive
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Dec 16, 2019
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
dtolnay
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Dec 16, 2019
Member
Thanks @derekdreery! This looks good to me. Could you please file a tracking issue and put the issue number into the #[unstable(...)] attribute in the PR? After that I'm happy to merge this. |
DebugStruct::non_exhaustive and DebugStruct::opaque_field.DebugStruct::non_exhaustive.richard-uk1
commented
Dec 17, 2019
ContributorAuthor
Tracking issue added :) |
Mark-Simulacrum
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Dec 17, 2019
Member
Could you also squash the commits down into just one? Thanks! It would also be good to update the PR description to be slightly more commit-y -- e.g., removing open questions, etc. -- since it'll go into the bors merge commit, so is preserved for all history. This is more of a personal pet peeve of mine though :) |
CAD97
commented
Dec 17, 2019
Contributor
Off topic question: bors-ng has a setting where you can ignore any part of the PR description after some special line, which I often set to e.g. Is this something that the rust-lang bors is capable of doing? If not, should we add it? If so, should we enable it and teach people to use it? |
richard-uk1force-pushed
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985127cComparerichard-uk1
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Dec 17, 2019
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Done and done. |
Mark-Simulacrum
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Dec 17, 2019
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bors
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Dec 17, 2019
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📌 Commit 985127c has been approved by |
bors
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Dec 17, 2019
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🌲 The tree is currently closed for pull requests below priority 100, this pull request will be tested once the tree is reopened |
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Dec 18, 2019
…=dtolnay
Implement `DebugStruct::non_exhaustive`.
This patch adds a function (finish_non_exhaustive) to add ellipsis before the closing brace when formatting using `DebugStruct`.
## Example
```rust
#![feature(debug_non_exhaustive)]
use std::fmt;
struct Bar {
bar: i32,
hidden: f32,
}
impl fmt::Debug for Bar {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar)
.non_exhaustive(true) // Show that some other field(s) exist.
.finish()
}
}
assert_eq!(
format!("{:?}", Bar { bar: 10, hidden: 1.0 }),
"Bar { bar: 10, .. }",
);
```rust-highfive
commented
Dec 19, 2019
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
bors
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Dec 19, 2019
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💔 Test failed - checks-azure |
bors
commented
Dec 23, 2019
Collaborator
☔ The latest upstream changes (presumably #67540) made this pull request unmergeable. Please resolve the merge conflicts. |
dtolnay
commented
Jan 14, 2020
Member
This needs a rebase but is otherwise ready to land. |
rust-highfive
commented
Jan 14, 2020
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
richard-uk1force-pushed
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9864ec4Comparerichard-uk1
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Jan 14, 2020
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Should be up-to-date now. |
rust-highfive
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Jan 14, 2020
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
dtolnay
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Jan 14, 2020
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https://dev.azure.com/rust-lang/e71b0ddf-dd27-435a-873c-e30f86eea377/_apis/build/builds/18417/logs/66 looks like it wants a rustfmt of these files. |
richard-uk1
commented
Jan 16, 2020
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ready for review |
dtolnay
commented
Jan 16, 2020
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Thanks! @bors r+ |
bors
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Jan 16, 2020
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📌 Commit 73124df has been approved by |
bors
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Jan 17, 2020
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bors added a commit
that referenced
this pull request
Jan 17, 2020
Implement `DebugStruct::non_exhaustive`.
This patch adds a function (finish_non_exhaustive) to add ellipsis before the closing brace when formatting using `DebugStruct`.
## Example
```rust
#![feature(debug_non_exhaustive)]
use std::fmt;
struct Bar {
bar: i32,
hidden: f32,
}
impl fmt::Debug for Bar {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar)
.non_exhaustive(true) // Show that some other field(s) exist.
.finish()
}
}
assert_eq!(
format!("{:?}", Bar { bar: 10, hidden: 1.0 }),
"Bar { bar: 10, .. }",
);
```bors
commented
Jan 17, 2020
Collaborator
☀️ Test successful - checks-azure |
5 tasks
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This patch adds a function (finish_non_exhaustive) to add ellipsis before the closing brace when formatting using
DebugStruct.Example