[cargo-nextest] make version computation less expensive

Realized that os_info would do a ton of calls that aren't necessary, slowing
down nextest quite measurably. It's hard to integrate lazy version evaluation
into clap (clap-rs/clap#5543) so let's just not print
OS info for now.

If we do want OS info in the future it'll probably be as part of a support
tarball or similar.

Cargo.toml

@@ -81,7 +81,6 @@ nextest-metadata = { version = "0.12.1", path = "nextest-metadata" }
 nextest-workspace-hack = "0.1.0"
 nix = { version = "0.29.0", default-features = false, features = ["signal"] }
 once_cell = "1.19.0"
-os_info = "3.8.2"
 owo-colors = "4.1.0"
 pathdiff = { version = "0.2.1", features = ["camino"] }
 pin-project-lite = "0.2.14"

cargo-nextest/Cargo.toml

@@ -14,7 +14,7 @@ rust-version.workspace = true
 [dependencies]
 camino.workspace = true
 cfg-if.workspace = true
-clap = { workspace = true, features = ["derive", "env", "string", "unicode", "wrap_help"] }
+clap = { workspace = true, features = ["derive", "env", "unicode", "wrap_help"] }
 color-eyre.workspace = true
 dialoguer.workspace = true
 duct.workspace = true
@@ -31,7 +31,6 @@ nextest-metadata = { version = "=0.12.1", path = "../nextest-metadata" }
 nextest-runner = { version = "=0.61.0", path = "../nextest-runner" }
 nextest-workspace-hack.workspace = true
 once_cell.workspace = true
-os_info.workspace = true
 owo-colors.workspace = true
 pathdiff.workspace = true
 quick-junit.workspace = true

cargo-nextest/src/dispatch.rs

@@ -5,8 +5,7 @@ use crate::{
     cargo_cli::{CargoCli, CargoOptions},
     output::{should_redact, OutputContext, OutputOpts, OutputWriter, StderrStyles},
     reuse_build::{make_path_mapper, ArchiveFormatOpt, ReuseBuildOpts},
-    version::VersionInfo,
-    ExpectedError, Result, ReuseBuildKind,
+    version, ExpectedError, Result, ReuseBuildKind,
 };
 use camino::{Utf8Path, Utf8PathBuf};
 use clap::{builder::BoolishValueParser, ArgAction, Args, Parser, Subcommand, ValueEnum};
@@ -66,8 +65,8 @@ use swrite::{swrite, SWrite};
 /// this message will not be seen), not `cargo-nextest`.
 #[derive(Debug, Parser)]
 #[command(
-    version = VersionInfo::new().to_short_string(),
-    long_version = VersionInfo::new().to_long_string(),
+    version = version::short(),
+    long_version = version::long(),
     bin_name = "cargo",
     styles = crate::output::clap_styles::style(),
     max_term_width = 100,
@@ -122,8 +121,8 @@ enum NextestSubcommand {
 
 #[derive(Debug, Args)]
 #[clap(
-    version = VersionInfo::new().to_short_string(),
-    long_version = VersionInfo::new().to_long_string(),
+    version = version::short(),
+    long_version = version::long(),
     display_name = "cargo-nextest",
 )]
 struct AppOpts {

cargo-nextest/src/version.rs

@@ -1,27 +1,49 @@
 // Copyright (c) The nextest Contributors
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
+use once_cell::sync::Lazy;
 use std::fmt::Write;
 
-pub(crate) struct VersionInfo {
+pub(crate) fn short() -> &'static str {
+    &VERSION_INFO.short
+}
+
+pub(crate) fn long() -> &'static str {
+    &VERSION_INFO.long
+}
+
+// All the data here is static so we can use a singleton.
+static VERSION_INFO: Lazy<VersionInfo> = Lazy::new(|| {
+    let inner = VersionInfoInner::new();
+    let short = inner.to_short();
+    let long = inner.to_long();
+    VersionInfo { short, long }
+});
+
+struct VersionInfo {
+    short: String,
+    long: String,
+}
+
+struct VersionInfoInner {
     /// Nextest's version.
     version: &'static str,
 
-    /// Information about the Git repository that nextest was built from.
+    /// Information about the repository that nextest was built from.
     ///
-    /// `None` if the Git repository information is not available.
+    /// `None` if the repository information is not available.
     commit_info: Option<CommitInfo>,
 }
 
-impl VersionInfo {
-    pub(crate) const fn new() -> Self {
+impl VersionInfoInner {
+    const fn new() -> Self {
         Self {
             version: env!("CARGO_PKG_VERSION"),
             commit_info: CommitInfo::from_env(),
         }
     }
 
-    pub(crate) fn to_short_string(&self) -> String {
+    pub(crate) fn to_short(&self) -> String {
         let mut s = self.version.to_string();
 
         if let Some(commit_info) = &self.commit_info {
@@ -36,16 +58,22 @@ impl VersionInfo {
         s
     }
 
-    pub(crate) fn to_long_string(&self) -> String {
-        let mut s = self.to_short_string();
+    pub(crate) fn to_long(&self) -> String {
+        let mut s = self.to_short();
         write!(s, "\nrelease: {}", self.version).unwrap();
 
         if let Some(commit_info) = &self.commit_info {
             write!(s, "\ncommit-hash: {}", commit_info.commit_hash).unwrap();
             write!(s, "\ncommit-date: {}", commit_info.commit_date).unwrap();
         }
         write!(s, "\nhost: {}", env!("NEXTEST_BUILD_HOST_TARGET")).unwrap();
-        write!(s, "\nos: {}", os_info::get()).unwrap();
+
+        // rustc and cargo's version also prints host info here. Unfortunately, clap 4.0's version
+        // support only supports a static string rather than a callback, so version info computation
+        // can't be deferred. OS info is also quite expensive to compute.
+        //
+        // For now, just don't do this -- everything else can be statically computed. We'll probably
+        // add a dedicated command to collect support data if it's necessary.
 
         s
     }

workspace-hack/Cargo.toml

@@ -17,8 +17,8 @@ publish = false
 [dependencies]
 backtrace = { version = "0.3.71", features = ["gimli-symbolize"] }
 camino = { version = "1.1.9", default-features = false, features = ["serde1"] }
-clap = { version = "4.5.18", features = ["derive", "env", "string", "unicode", "wrap_help"] }
-clap_builder = { version = "4.5.18", default-features = false, features = ["color", "env", "std", "string", "suggestions", "unicode", "usage", "wrap_help"] }
+clap = { version = "4.5.18", features = ["derive", "env", "unicode", "wrap_help"] }
+clap_builder = { version = "4.5.18", default-features = false, features = ["color", "env", "std", "suggestions", "unicode", "usage", "wrap_help"] }
 console = { version = "0.15.8" }
 either = { version = "1.13.0" }
 getrandom = { version = "0.2.15", default-features = false, features = ["std"] }
@@ -74,6 +74,6 @@ futures-sink = { version = "0.3.30", default-features = false, features = ["std"
 smallvec = { version = "1.13.2", default-features = false, features = ["const_new"] }
 tokio = { version = "1.40.0", default-features = false, features = ["io-std", "net"] }
 windows-sys-73dcd821b1037cfd = { package = "windows-sys", version = "0.59.0", features = ["Win32_Globalization", "Win32_Security", "Win32_Storage_FileSystem", "Win32_System_Console", "Win32_System_JobObjects", "Win32_System_Pipes", "Win32_System_Threading"] }
-windows-sys-b21d60becc0929df = { package = "windows-sys", version = "0.52.0", features = ["Wdk_Foundation", "Wdk_Storage_FileSystem", "Wdk_System_IO", "Win32_Foundation", "Win32_Networking_WinSock", "Win32_Security", "Win32_Storage_FileSystem", "Win32_System_Com", "Win32_System_Console", "Win32_System_Environment", "Win32_System_IO", "Win32_System_LibraryLoader", "Win32_System_Memory", "Win32_System_Pipes", "Win32_System_Registry", "Win32_System_SystemInformation", "Win32_System_SystemServices", "Win32_System_Threading", "Win32_System_WindowsProgramming", "Win32_UI_Input_KeyboardAndMouse", "Win32_UI_Shell", "Win32_UI_WindowsAndMessaging"] }
+windows-sys-b21d60becc0929df = { package = "windows-sys", version = "0.52.0", features = ["Wdk_Foundation", "Wdk_Storage_FileSystem", "Wdk_System_IO", "Win32_Foundation", "Win32_Networking_WinSock", "Win32_Security", "Win32_Storage_FileSystem", "Win32_System_Com", "Win32_System_Console", "Win32_System_Environment", "Win32_System_IO", "Win32_System_LibraryLoader", "Win32_System_Memory", "Win32_System_Pipes", "Win32_System_SystemServices", "Win32_System_Threading", "Win32_System_WindowsProgramming", "Win32_UI_Input_KeyboardAndMouse", "Win32_UI_Shell"] }
 
 ### END HAKARI SECTION