Run Miri in a GitHub workflow

Miri is an undefined behavior detection tool for Rust. This PR adds a
GitHub workflow that runs TrieDB's tests under Miri to detect potential
undefined behavior in the code base.

Author: and-cb

.github/workflows/miri.yml

@@ -0,0 +1,41 @@
+name: PR
+
+on:
+  push:
+    branches: [ main ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  miri:
+    strategy:
+      matrix:
+        partition: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Harden the runner (Audit all outbound calls)
+      uses: step-security/harden-runner@6c439dc8bdf85cadbbce9ed30d1c7b959517bc49 # v2.12.2
+      with:
+        egress-policy: audit
+
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+    - uses: dtolnay/rust-toolchain@b95584d8105b9ab200e15821fa671848cf2b7017 # nightly
+      with:
+        components: miri
+
+    - name: Install cargo-nextest
+      run: |
+        cargo install --locked cargo-nextest
+
+    - name: Run unit tests under Miri
+      run: |
+        MIRIFLAGS=-Zmiri-disable-isolation cargo +nightly miri nextest run \
+          --partition=hash:${{ matrix.partition }}/10 \
+          --test-threads=$(nproc)

.github/workflows/pr.yml

@@ -2,8 +2,12 @@ name: PR
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ main ]
   pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
 
 env:
   CARGO_TERM_COLOR: always
@@ -96,3 +100,31 @@ jobs:
     - name: Run integration tests
       run:
         make integration-tests cargo_flags=--profile=${{ matrix.profile }} test_flags=--nocapture
+
+  miri:
+    strategy:
+      matrix:
+        partition: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Harden the runner (Audit all outbound calls)
+      uses: step-security/harden-runner@6c439dc8bdf85cadbbce9ed30d1c7b959517bc49 # v2.12.2
+      with:
+        egress-policy: audit
+
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+    - uses: dtolnay/rust-toolchain@b95584d8105b9ab200e15821fa671848cf2b7017 # nightly
+      with:
+        components: "miri, rust-src"
+    - uses: cargo-bins/cargo-binstall@main
+    - name: Install cargo-nextest
+      run: |
+        cargo binstall cargo-nextest --secure
+
+    - name: Run unit tests under Miri
+      run: |
+        MIRIFLAGS=-Zmiri-disable-isolation cargo +nightly miri nextest run \
+          --partition=hash:${{ matrix.partition }}/10 \
+          --test-threads=$(nproc)

src/database.rs

@@ -364,6 +364,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore = "persistence is not implemented with miri")]
     fn test_data_persistence() {
         let tmp_dir = TempDir::new("test_db").unwrap();
         let file_path = tmp_dir.path().join("test.db");

src/meta/mod.rs

@@ -749,6 +749,7 @@ mod tests {
     use crate::page::page_id;
 
     #[test]
+    #[cfg_attr(miri, ignore = "persistence is not implemented with miri")]
     fn persistence() {
         let f = tempfile::tempfile().expect("failed to open temporary file");
         let mut manager =
@@ -912,6 +913,7 @@ mod tests {
         }
 
         #[test]
+        #[cfg_attr(miri, ignore = "persistence is not implemented with miri")]
         fn crash_recovery() {
             let f = tempfile::tempfile().expect("failed to open temporary file");
             let mut manager =

src/page/manager/options.rs

@@ -18,10 +18,12 @@ impl PageManagerOptions {
 
         let max_pages = if cfg!(not(test)) {
             Page::MAX_COUNT
-        } else {
+        } else if cfg!(not(miri)) {
             // Because tests run in parallel, it's easy to exhaust the address space, so use a more
             // conservative limit
             Page::MAX_COUNT / 1024
+        } else {
+            2048
         };
 
         Self { open_options, page_count: 0, max_pages }