Replace unmaintained humantime crate with jiff (#15290)

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The crate [`humantime`](https://crates.io/crates/humantime) appears to
be unmaintained. There's open PR in RustSec's advisory-db about this:
rustsec/advisory-db#2249

The crates [`clap`](https://crates.io/crates/clap) and
[`env_logger`](https://crates.io/crates/env_logger) have already made
the switch from `humantime` to [`jiff`](https://crates.io/crates/jiff):

 * clap-rs/clap#5944
 * rust-cli/env_logger#352

The `jiff` crate is already dependency on `cargo` via `gix` (albeit old
0.1 version, but that's probably fixed in [next gix
release](GitoxideLabs/gitoxide@3ae99a4)):

```
jiff v0.1.29
└── gix-date v0.9.3
    ├── gix v0.70.0
    │   └── cargo v0.88.0 (/Users/oherrala/rust/cargo)
```

This PR shouldn't have any functional change to cargo itself.

Cargo.toml

@@ -55,11 +55,11 @@ hex = "0.4.3"
 hmac = "0.12.1"
 home = "0.5.11"
 http-auth = { version = "0.1.10", default-features = false }
-humantime = "2.1.0"
 ignore = "0.4.23"
 im-rc = "15.1.0"
 indexmap = "2.7.1"
 itertools = "0.14.0"
+jiff = { version = "0.2.3", default-features = false, features = [ "std" ] }
 jobserver = "0.1.32"
 lazycell = "1.3.0"
 libc = "0.2.169"
@@ -176,11 +176,11 @@ hex.workspace = true
 hmac.workspace = true
 home.workspace = true
 http-auth.workspace = true
-humantime.workspace = true
 ignore.workspace = true
 im-rc.workspace = true
 indexmap.workspace = true
 itertools.workspace = true
+jiff.workspace = true
 jobserver.workspace = true
 lazycell.workspace = true
 libgit2-sys.workspace = true

src/bin/cargo/main.rs

@@ -79,7 +79,7 @@ fn setup_logger() -> Option<ChromeFlushGuard> {
         .with(fmt_layer)
         .with(profile_layer);
     registry.init();
-    tracing::trace!(start = humantime::format_rfc3339(std::time::SystemTime::now()).to_string());
+    tracing::trace!(start = jiff::Timestamp::now().to_string());
     profile_guard
 }
 

src/cargo/core/compiler/fingerprint/dirty_reason.rs

@@ -102,12 +102,9 @@ impl fmt::Display for FileTimeDiff {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let s_diff = self.new_time.seconds() - self.old_time.seconds();
         if s_diff >= 1 {
-            fmt::Display::fmt(
-                &humantime::Duration::from(std::time::Duration::from_secs(s_diff as u64)),
-                f,
-            )
+            write!(f, "{:#}", jiff::SignedDuration::from_secs(s_diff))
         } else {
-            // format nanoseconds as it is, humantime would display ms, us and ns
+            // format nanoseconds as it is, jiff would display ms, us and ns
             let ns_diff = self.new_time.nanoseconds() - self.old_time.nanoseconds();
             write!(f, "{ns_diff}ns")
         }

src/cargo/core/compiler/timings.rs

@@ -15,7 +15,7 @@ use cargo_util::paths;
 use std::collections::HashMap;
 use std::io::{BufWriter, Write};
 use std::thread::available_parallelism;
-use std::time::{Duration, Instant, SystemTime};
+use std::time::{Duration, Instant};
 
 /// Tracking information for the entire build.
 ///
@@ -117,7 +117,7 @@ impl<'gctx> Timings<'gctx> {
                 (pkg_desc, targets)
             })
             .collect();
-        let start_str = humantime::format_rfc3339_seconds(SystemTime::now()).to_string();
+        let start_str = jiff::Timestamp::now().to_string();
         let profile = bcx.build_config.requested_profile.to_string();
         let last_cpu_state = if enabled {
             match State::current() {