sieve: Use saturating_add when computing next_base

.github/workflows/ci.yml

@@ -2,8 +2,8 @@ name: Continuous integration
 on:
   push:
     branches:
-      - staging
-      - trying
+      - master
+  pull_request:
 
 env:
   CARGO_TERM_COLOR: always
@@ -21,10 +21,10 @@ jobs:
           - rust: nightly
           - rust: nightly-i686-unknown-linux-gnu
           - rust: stable
-            target: mips64-unknown-linux-gnuabi64
+            target: s390x-unknown-linux-gnu
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
@@ -35,3 +35,18 @@ jobs:
         env:
           TARGET: ${{ matrix.target }}
         run: ./ci/script.sh
+
+  # One job that "summarizes" the success state of this pipeline. This can then be added to branch
+  # protection, rather than having to add each job separately.
+  success:
+    name: bors
+    runs-on: ubuntu-latest
+    needs: [tests]
+    # Github branch protection is exceedingly silly and treats "jobs skipped because a dependency
+    # failed" as success. So we have to do some contortions to ensure the job fails if any of its
+    # dependencies fails.
+    if: always() # make sure this is never "skipped"
+    steps:
+      # Manually check the status of all dependencies. `if: failure()` does not work.
+      - name: check if any dependency failed
+        run: jq --exit-status 'all(.result == "success")' <<< '${{ toJson(needs) }}'

Cargo.toml

@@ -52,3 +52,8 @@ tag-name = "{{crate_name}}-{{version}}"
 [package.metadata.release]
 sign-tag = true
 tag-name = "{{crate_name}}-{{version}}"
+
+# Make sure all our slow_tests still check overflows in --release tests.
+# (This doesn't affect downstream dependents building these libraries.)
+[profile.release]
+overflow-checks = true

primal-sieve/src/sieve.rs

@@ -358,7 +358,7 @@ impl Sieve {
         let bits = &self.seen[base].bits;
 
         let current_base = base_byte_count * wheel::BYTE_MODULO;
-        let next_base = current_base + bits.len() * wheel::BYTE_MODULO / 8;
+        let next_base = current_base.saturating_add(bits.len() * wheel::BYTE_MODULO / 8);
 
         SievePrimes {
             early,
@@ -404,7 +404,9 @@ impl<'a> SievePrimes<'a> {
         match self.bits.next() {
             Some(Item { bits, .. }) => {
                 self.base = self.next_base;
-                self.next_base += bits.len() * wheel::BYTE_MODULO / 8;
+                self.next_base = self
+                    .next_base
+                    .saturating_add(bits.len() * wheel::BYTE_MODULO / 8);
                 self.ones = bits.ones_from(0);
                 true
             },