builder: apply fixed offset before relative adjustments

A fixed offset (e.g. the "UTC" keyword) was applied after relative
items, so "1970/01/01 UTC N seconds" added N seconds to a local
wall-clock that could drift across a DST boundary before being
re-anchored at the offset, yielding an instant off by the DST gap.
Anchor the offset first, then apply relative items.

Fixes uutils/coreutils#12555.

.github/workflows/audit.yml

@@ -0,0 +1,15 @@
+name: Security audit
+
+on:
+  schedule:
+    - cron: "0 0 * * *"
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - uses: rustsec/audit-check@v2
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -131,7 +131,7 @@ jobs:
         grcov . --binary-path="${COVERAGE_REPORT_DIR}" --output-type lcov --output-path "${COVERAGE_REPORT_FILE}" --branch --ignore build.rs --ignore "vendor/*" --ignore "/*" --ignore "[a-zA-Z]:/*" --excl-br-line "^\s*((debug_)?assert(_eq|_ne)?!|#\[derive\()" --source-dir .
         echo "report=${COVERAGE_REPORT_FILE}" >> $GITHUB_OUTPUT
     - name: Upload coverage results (to Codecov.io)
-      uses: codecov/codecov-action@v6
+      uses: codecov/codecov-action@v7
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: ${{ steps.coverage.outputs.report }}

Cargo.lock

@@ -138,9 +138,9 @@ checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
 
 [[package]]
 name = "codspeed"
-version = "4.4.1"
+version = "4.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b684e94583e85a5ca7e1a6454a89d76a5121240f2fb67eb564129d9bafdb9db0"
+checksum = "57af92d1db7f6871b7e82c79cd87f2501db66f36b0eab924be6ea83dd6b2f3f3"
 dependencies = [
  "anyhow",
  "cc",
@@ -156,9 +156,9 @@ dependencies = [
 
 [[package]]
 name = "codspeed-criterion-compat"
-version = "4.4.1"
+version = "4.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e65444156eb73ad7f57618188f8d4a281726d133ef55b96d1dcff89528609ab"
+checksum = "1d31ae2e9ab23c29fa13bdfa06d012524176f5c0f4e25ec262cd829d947ebc5e"
 dependencies = [
  "clap",
  "codspeed",
@@ -169,9 +169,9 @@ dependencies = [
 
 [[package]]
 name = "codspeed-criterion-compat-walltime"
-version = "4.4.1"
+version = "4.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96389aaa4bbb872ea4924dc0335b2bb181bcf28d6eedbe8fea29afcc5bde36a6"
+checksum = "cc8605e40bab5114dcb0f76268e18880082b5798dec10757b5b58d2c3bbc7a1c"
 dependencies = [
  "anes",
  "cast",
@@ -201,7 +201,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "117725a109d387c937a1533ce01b450cbde6b88abceea8473c4d7a85853cda3c"
 dependencies = [
  "lazy_static",
- "windows-sys 0.59.0",
+ "windows-sys",
 ]
 
 [[package]]
@@ -364,7 +364,7 @@ checksum = "3640c1c38b8e4e43584d8df18be5fc6b0aa314ce6ebf51b53313d4306cca8e46"
 dependencies = [
  "hermit-abi",
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys",
 ]
 
 [[package]]
@@ -384,9 +384,9 @@ checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
 [[package]]
 name = "jiff"
-version = "0.2.23"
+version = "0.2.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a3546dc96b6d42c5f24902af9e2538e82e39ad350b0c766eb3fbf2d8f3d8359"
+checksum = "4603d3033e49e2b0e31229fcab20a5d40089c607d975cd9c80551dc69eed9102"
 dependencies = [
  "jiff-static",
  "jiff-tzdb-platform",
@@ -394,14 +394,14 @@ dependencies = [
  "portable-atomic",
  "portable-atomic-util",
  "serde_core",
- "windows-sys 0.61.2",
+ "windows-link",
 ]
 
 [[package]]
 name = "jiff-static"
-version = "0.2.23"
+version = "0.2.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a8c8b344124222efd714b73bb41f8b5120b27a7cc1c75593a6ff768d9d05aa4"
+checksum = "782d32378dddf207193ac91cefb848ad41abb58195c95168e1291227a0832b47"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -498,7 +498,7 @@ dependencies = [
  "jiff",
  "num-traits",
  "rstest",
- "winnow 1.0.1",
+ "winnow 1.0.3",
 ]
 
 [[package]]
@@ -896,7 +896,7 @@ version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys",
 ]
 
 [[package]]
@@ -914,15 +914,6 @@ dependencies = [
  "windows-targets",
 ]
 
-[[package]]
-name = "windows-sys"
-version = "0.61.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
-dependencies = [
- "windows-link",
-]
-
 [[package]]
 name = "windows-targets"
 version = "0.52.6"
@@ -998,9 +989,9 @@ dependencies = [
 
 [[package]]
 name = "winnow"
-version = "1.0.1"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "09dac053f1cd375980747450bfc7250c264eaae0583872e845c0c7cd578872b5"
+checksum = "0592e1c9d151f854e6fd382574c3a0855250e1d9b2f99d9281c6e6391af352f1"
 dependencies = [
  "memchr",
 ]

fuzz/Cargo.lock

@@ -76,9 +76,9 @@ dependencies = [
 
 [[package]]
 name = "jiff"
-version = "0.2.23"
+version = "0.2.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a3546dc96b6d42c5f24902af9e2538e82e39ad350b0c766eb3fbf2d8f3d8359"
+checksum = "4603d3033e49e2b0e31229fcab20a5d40089c607d975cd9c80551dc69eed9102"
 dependencies = [
  "jiff-static",
  "jiff-tzdb-platform",
@@ -86,14 +86,14 @@ dependencies = [
  "portable-atomic",
  "portable-atomic-util",
  "serde_core",
- "windows-sys",
+ "windows-link",
 ]
 
 [[package]]
 name = "jiff-static"
-version = "0.2.23"
+version = "0.2.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a8c8b344124222efd714b73bb41f8b5120b27a7cc1c75593a6ff768d9d05aa4"
+checksum = "782d32378dddf207193ac91cefb848ad41abb58195c95168e1291227a0832b47"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -133,9 +133,9 @@ checksum = "b5b646652bf6661599e1da8901b3b9522896f01e736bad5f723fe7a3a27f899d"
 
 [[package]]
 name = "libfuzzer-sys"
-version = "0.4.12"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f12a681b7dd8ce12bff52488013ba614b869148d54dd79836ab85aafdd53f08d"
+checksum = "a9fd2f41a1cba099f79a0b6b6c35656cf7c03351a7bae8ff0f28f25270f929d2"
 dependencies = [
  "arbitrary",
  "cc",
@@ -268,20 +268,11 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
-[[package]]
-name = "windows-sys"
-version = "0.61.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
-dependencies = [
- "windows-link",
-]
-
 [[package]]
 name = "winnow"
-version = "0.7.15"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df79d97927682d2fd8adb29682d1140b343be4ac0f08fd68b7765d9c059d3945"
+checksum = "2ee1708bef14716a11bae175f579062d4554d95be2c6829f518df847b7b3fdd0"
 dependencies = [
  "memchr",
 ]

src/items/builder.rs

@@ -189,8 +189,8 @@ impl DateTimeBuilder {
     ///   - b. Apply time. If time carries an explicit numeric offset, apply the
     ///     offset before setting time.
     ///   - c. Apply weekday (e.g., "next Friday" or "last Monday").
-    ///   - d. Apply relative adjustments (e.g., "+3 days", "-2 months").
-    ///   - e. Apply final fixed offset if present.
+    ///   - d. Apply fixed offset if present (anchors the instant).
+    ///   - e. Apply relative adjustments (e.g., "+3 days", "-2 months").
     pub(super) fn build(self) -> Result<ParsedDateTime, error::Error> {
         if let Some(date) = self.date.as_ref() {
             if date.year.unwrap_or(0) > 9999 {
@@ -317,7 +317,17 @@ impl DateTimeBuilder {
             dt = dt.checked_add(Span::new().try_days(delta)?)?;
         }
 
-        // 4d. Apply relative adjustments.
+        // 4d. Apply fixed offset. This anchors the instant before relative
+        // adjustments so that "1970/01/01 UTC N seconds" adds N seconds to the
+        // fixed-offset instant rather than to a local wall-clock that may drift
+        // across a DST boundary (see issue uutils/coreutils#12555).
+        if let Some(offset) = self.offset {
+            let (offset, hour_adjustment) = offset.normalize();
+            dt = dt.checked_add(Span::new().hours(hour_adjustment))?;
+            dt = dt.datetime().to_zoned((&offset).try_into()?)?;
+        }
+
+        // 4e. Apply relative adjustments.
         for rel in self.relative {
             dt = match rel {
                 relative::Relative::Years(_) | relative::Relative::Months(_) => {
@@ -338,13 +348,6 @@ impl DateTimeBuilder {
             };
         }
 
-        // 4e. Apply final fixed offset.
-        if let Some(offset) = self.offset {
-            let (offset, hour_adjustment) = offset.normalize();
-            dt = dt.checked_add(Span::new().hours(hour_adjustment))?;
-            dt = dt.datetime().to_zoned((&offset).try_into()?)?;
-        }
-
         Ok(dt)
     }
 

tests/date.rs

@@ -285,3 +285,31 @@ fn test_multiple_month_skip(#[case] base: &str, #[case] input: &str, #[case] exp
 fn test_embedded_timezone(#[case] input: &str, #[case] expected: &str) {
     check_absolute(input, expected);
 }
+
+// Regression test for uutils/coreutils#12555.
+// A fixed offset (e.g. the "UTC" keyword) must anchor the instant *before*
+// relative adjustments are applied. Otherwise, when the base zone observes DST,
+// adding a large relative offset drifts the wall-clock across a DST boundary
+// and re-anchoring at the fixed offset bakes in the extra hour.
+// "1970-01-01 UTC + N seconds" must equal exactly N seconds after the epoch,
+// regardless of the base zone's DST rules.
+#[test]
+fn test_utc_keyword_plus_relative_seconds_across_dst() {
+    // Base in a DST-observing zone (Europe/Berlin); the value only matters as
+    // the default zone for interpreting the date, not the result.
+    let base = "2020-06-15 12:00:00"
+        .parse::<DateTime>()
+        .unwrap()
+        .to_zoned(TimeZone::get("Europe/Berlin").unwrap())
+        .unwrap();
+
+    // A timestamp landing in summer (CEST, UTC+2) while the epoch base is in
+    // winter (CET, UTC+1), so the DST offset differs between base and result.
+    let seconds = 1_780_318_971_i64;
+    let input = format!("1970-01-01 UTC {seconds} seconds");
+
+    let parsed = parse_datetime::parse_datetime_at_date(base, input)
+        .unwrap()
+        .expect_in_range();
+    assert_eq!(parsed.timestamp().as_second(), seconds);
+}