Reduce number of unwrap calls and make clippy warning for it opt-out …

…per crate (#6311)

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### What
Resolves #3408: Remove all usages of unwrap() and forbid it's use (if
applicable).

*If applicable* because even after the first batch of changes there are
over 800(!) usages of unwrap() in the code - for various reasons, and
often explicitly allowed. So I think it's probably unrealistic to get
rid of all of them, and probably also not necessary.

The strategy:
1. Warn on all usages of `unwrap()`.
2. Remove `unwrap()` module by module.
3. Where `unwrap()` would be theoretically okay use `expect("error
msg")`.
4. Leave build tools as they are for now - panics there are annoying but
not critical (can happen when e.g. some command line tool is missing).
5. For tests and benchmarks unwrap is totally okay imho
(`allow-unwrap-in-tests` was anyway already set in `clippy.toml`)
6. Where errors are returned combine error types and "?-ify" the code,
or use some other idiomatic Rust expression.
7. Goal: eventually deny `clippy::unwrap_used` everywhere, unless
explicitly allowed.

*Note: as this is my first PR, early feedback is greatly appreciated*🙏
Also - rookie question - what (or where) are the guidelines for the last
three items in the checklist? Are they needed for this PR, as this is
just a cleanup?

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG

- [PR Build Summary](https://build.rerun.io/pr/6311)
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

To run all checks from `main`, comment on the PR with `@rerun-bot
full-check`.

Cargo.toml

@@ -444,7 +444,7 @@ missing_errors_doc = "allow"
 # This would be nice to enable, but we have way too many unwraps right now 😭
 # Enabling this lint in 2023-04-27 yielded 556 hits.
 # Enabling this lint in 2023-09-23 yielded 352 hits
-unwrap_used = "allow"
+unwrap_used = "warn"
 
 [patch.crates-io]
 # Try to avoid patching crates! It prevents us from publishing the crates on crates.io.

crates/re_analytics/examples/end_to_end.rs

@@ -4,17 +4,17 @@ use re_analytics::Event;
 use re_analytics::Properties;
 use re_analytics::{Analytics, AnalyticsEvent};
 
-fn main() -> ! {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     re_log::setup_logging();
 
-    let analytics = Analytics::new(Duration::from_secs(3)).unwrap();
+    let analytics = Analytics::new(Duration::from_secs(3))?;
     let application_id = "end_to_end_example".to_owned();
     let recording_id = uuid::Uuid::new_v4().to_string();
 
     println!("any non-empty line written here will be sent as an analytics datapoint");
     loop {
         let mut input = String::new();
-        std::io::stdin().read_line(&mut input).unwrap();
+        std::io::stdin().read_line(&mut input)?;
 
         let input = input.trim();
         if !input.is_empty() {

crates/re_analytics/src/native/config.rs

@@ -106,7 +106,9 @@ impl Config {
     }
 
     pub fn config_dir(&self) -> &Path {
-        self.config_file_path.parent().unwrap()
+        self.config_file_path
+            .parent()
+            .expect("config file has no parent")
     }
 
     pub fn config_file(&self) -> &Path {

crates/re_build_info/src/build_info.rs

@@ -166,8 +166,8 @@ fn crate_version_from_build_info_string() {
 
     {
         let expected_crate_version = build_info.version;
-        let crate_version = CrateVersion::try_parse_from_build_info_string(build_info_str).unwrap();
+        let crate_version = CrateVersion::try_parse_from_build_info_string(build_info_str);
 
-        assert_eq!(expected_crate_version, crate_version);
+        assert_eq!(Ok(expected_crate_version), crate_version);
     }
 }

crates/re_build_tools/src/hashing.rs

@@ -12,7 +12,7 @@ use crate::{rerun_if_changed, rerun_if_changed_or_doesnt_exist};
 fn encode_hex(bytes: &[u8]) -> String {
     let mut s = String::with_capacity(bytes.len() * 2);
     for &b in bytes {
-        write!(&mut s, "{b:02x}").unwrap();
+        write!(&mut s, "{b:02x}").expect("writing to string should never fail");
     }
     s
 }

crates/re_data_store/benches/arrow2.rs

@@ -1,5 +1,8 @@
 //! Keeping track of performance issues/regressions in `arrow2` that directly affect us.
 
+// Allow unwrap() in benchmarks
+#![allow(clippy::unwrap_used)]
+
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 

crates/re_data_store/benches/data_store.rs

@@ -1,3 +1,6 @@
+// Allow unwrap() in benchmarks
+#![allow(clippy::unwrap_used)]
+
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 

crates/re_data_store/benches/gc.rs

@@ -1,3 +1,6 @@
+// Allow unwrap() in benchmarks
+#![allow(clippy::unwrap_used)]
+
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 

crates/re_data_store/src/lib.rs

@@ -14,6 +14,9 @@
 #![doc = document_features::document_features!()]
 //!
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 mod arrow_util;
 mod store;
 mod store_arrow;

crates/re_data_store/tests/correctness.rs

@@ -2,6 +2,9 @@
 //!
 //! Bending and twisting the datastore APIs in all kinds of weird ways to try and break them.
 
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use rand::Rng;
 
 use re_data_store::{

crates/re_data_store/tests/data_store.rs

@@ -2,6 +2,9 @@
 //!
 //! Testing & demonstrating expected usage of the datastore APIs, no funny stuff.
 
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use itertools::Itertools;
 use rand::Rng;
 use re_data_store::{

crates/re_data_store/tests/dump.rs

@@ -1,5 +1,8 @@
 //! Dumping a datastore to log messages and back.
 
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use itertools::Itertools;
 use re_data_store::{
     test_row,

crates/re_data_store/tests/internals.rs

@@ -2,6 +2,9 @@
 //!
 //! They're awful, but sometimes you just have to…
 
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use re_data_store::{DataStore, DataStoreConfig};
 use re_log_types::{
     build_frame_nr, example_components::MyIndex, DataRow, EntityPath, RowId, TimePoint,

crates/re_data_store/tests/memory_test.rs

@@ -1,5 +1,8 @@
 //! Measures the memory overhead of the data store.
 
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
 
 thread_local! {

crates/re_dev_tools/src/main.rs

@@ -2,6 +2,9 @@
 //!
 //! To get an overview over all tools run `pixi run dev-tools --help`.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use argh::FromArgs;
 
 mod build_examples;

crates/re_entity_db/examples/memory_usage.rs

@@ -1,3 +1,6 @@
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
 
 thread_local! {

crates/re_entity_db/src/lib.rs

@@ -4,6 +4,9 @@
 #![doc = document_features::document_features!()]
 //!
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 pub mod entity_db;
 pub mod entity_properties;
 pub mod entity_tree;

crates/re_entity_db/tests/clear.rs

@@ -1,3 +1,6 @@
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use re_data_store::{DataStore, LatestAtQuery};
 use re_entity_db::EntityDb;
 use re_log_types::{

crates/re_entity_db/tests/time_histograms.rs

@@ -1,3 +1,6 @@
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use std::collections::BTreeSet;
 
 use re_data_store::GarbageCollectionOptions;

crates/re_format_arrow/src/lib.rs

@@ -1,5 +1,8 @@
 //! Formatting for tables of Arrow arrays
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use std::fmt::Formatter;
 
 use arrow2::{

crates/re_log_encoding/benches/msg_encode_benchmark.rs

@@ -1,3 +1,6 @@
+// Allow unwrap() in benchmarks
+#![allow(clippy::unwrap_used)]
+
 #[cfg(not(all(feature = "decoder", feature = "encoder")))]
 compile_error!("msg_encode_benchmark requires 'decoder' and 'encoder' features.");
 

crates/re_log_encoding/src/lib.rs

@@ -135,12 +135,14 @@ impl FileHeader {
 
     #[cfg(feature = "decoder")]
     pub fn decode(read: &mut impl std::io::Read) -> Result<Self, decoder::DecodeError> {
+        let to_array_4b = |slice: &[u8]| slice.try_into().expect("always returns an Ok() variant");
+
         let mut buffer = [0_u8; Self::SIZE];
         read.read_exact(&mut buffer)
             .map_err(decoder::DecodeError::Read)?;
-        let magic = buffer[0..4].try_into().unwrap();
-        let version = buffer[4..8].try_into().unwrap();
-        let options = EncodingOptions::from_bytes(buffer[8..].try_into().unwrap())?;
+        let magic = to_array_4b(&buffer[0..4]);
+        let version = to_array_4b(&buffer[4..8]);
+        let options = EncodingOptions::from_bytes(to_array_4b(&buffer[8..]))?;
         Ok(Self {
             magic,
             version,

crates/re_log_encoding/src/stream_rrd_from_http.rs

@@ -118,6 +118,8 @@ pub fn stream_rrd_from_http(url: String, on_msg: Arc<HttpMessageCallback>) {
 }
 
 #[cfg(target_arch = "wasm32")]
+// TODO(#3408): remove unwrap()
+#[allow(clippy::unwrap_used)]
 mod web_event_listener {
     use super::HttpMessageCallback;
     use js_sys::Uint8Array;
@@ -157,6 +159,8 @@ mod web_event_listener {
 pub use web_event_listener::stream_rrd_from_event_listener;
 
 #[cfg(target_arch = "wasm32")]
+// TODO(#3408): remove unwrap()
+#[allow(clippy::unwrap_used)]
 pub mod web_decode {
     use super::{HttpMessage, HttpMessageCallback};
     use std::sync::Arc;

crates/re_log_types/src/lib.rs

@@ -17,6 +17,9 @@
 //! e.g. the entity `foo/bar/baz` is has the transform that is the product of
 //! `foo.transform * foo/bar.transform * foo/bar/baz.transform`.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 pub mod arrow_msg;
 pub mod example_components;
 pub mod hash;

crates/re_query/benches/latest_at.rs

@@ -1,6 +1,9 @@
 //! Contains:
 //! - A 1:1 port of the benchmarks in `crates/re_query/benches/query_benchmarks.rs`, with caching enabled.
 
+// Allow unwrap() in benchmarks
+#![allow(clippy::unwrap_used)]
+
 use criterion::{criterion_group, criterion_main, Criterion};
 
 use itertools::Itertools;

crates/re_query/src/latest_at/results.rs

@@ -285,6 +285,8 @@ fn downcast<C: Component>(cached: &(dyn ErasedFlatVecDeque + Send + Sync)) -> cr
     if cached.num_entries() != 1 {
         return Err(anyhow::anyhow!("latest_at deque must be single entry").into());
     }
-    // unwrap checked just above ^^^
-    Ok(cached.iter().next().unwrap())
+    Ok(cached
+        .iter()
+        .next()
+        .expect("checked existence of cached value already"))
 }

crates/re_query/src/lib.rs

@@ -1,5 +1,8 @@
 //! Caching datastructures for `re_query`.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 mod cache;
 mod cache_stats;
 mod flat_vec_deque;

crates/re_query/tests/latest_at.rs

@@ -1,3 +1,6 @@
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use re_data_store::{DataStore, LatestAtQuery, StoreSubscriber};
 use re_log_types::{
     build_frame_nr,

crates/re_query/tests/range.rs

@@ -1,3 +1,6 @@
+// https://github.com/rust-lang/rust-clippy/issues/10011
+#![cfg(test)]
+
 use itertools::Itertools as _;
 
 use re_data_store::{DataStore, RangeQuery, ResolvedTimeRange, StoreSubscriber as _, TimeInt};

crates/re_renderer/src/lib.rs

@@ -7,6 +7,9 @@
 #![doc = document_features::document_features!()]
 //!
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 pub mod config;
 pub mod importer;
 pub mod mesh;

crates/re_renderer_examples/2d.rs

@@ -2,6 +2,9 @@
 //!
 //! On the left is a 2D view, on the right a 3D view of the same scene.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use itertools::Itertools as _;
 use re_renderer::Hsva;
 

crates/re_renderer_examples/depth_cloud.rs

@@ -13,6 +13,9 @@
 //! cargo run-wasm --example depth_cloud
 //! ```
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use std::f32::consts::TAU;
 
 use glam::Vec3;

crates/re_renderer_examples/depth_offset.rs

@@ -7,6 +7,9 @@
 //! Press arrow up/down to increase/decrease the distance of the camera to the z==0 plane in tandem with the scale of the rectangles.
 //! Press arrow left/right to increase/decrease the near plane distance.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use re_renderer::Hsva;
 use re_renderer::{
     renderer::{ColormappedTexture, RectangleDrawData, RectangleOptions, TexturedRect},

crates/re_renderer_examples/framework.rs

@@ -1,5 +1,8 @@
 //! Example framework
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use std::sync::Arc;
 
 use anyhow::Context as _;

crates/re_renderer_examples/multiview.rs

@@ -1,5 +1,8 @@
 //! Example with several independent views, using various primitives.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use std::f32::consts::TAU;
 
 use framework::Example;

crates/re_renderer_examples/outlines.rs

@@ -1,5 +1,8 @@
 //! Demonstrates outline rendering.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use itertools::Itertools;
 use re_renderer::{
     renderer::MeshInstance,

crates/re_renderer_examples/picking.rs

@@ -1,5 +1,8 @@
 //! Demonstrates the dedicated picking layer support.
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
+
 use itertools::Itertools as _;
 use rand::Rng;
 use re_renderer::{

crates/re_sdk/src/lib.rs

@@ -10,6 +10,8 @@
 #![doc = document_features::document_features!()]
 //!
 
+// TODO(#3408): remove unwrap()
+#![allow(clippy::unwrap_used)]
 #![warn(missing_docs)] // Let's keep the this crate well-documented!
 
 // ----------------