diff --git a/.github/workflows/_ci-flake.yml b/.github/workflows/_ci-flake.yml
index 37f6d228e1..f2b4f8c23e 100644
--- a/.github/workflows/_ci-flake.yml
+++ b/.github/workflows/_ci-flake.yml
@@ -75,7 +75,7 @@ jobs:
     steps:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
       - uses: cashapp/activate-hermit@cea9af7913204a965fd488637a8d1811bba2e616 # v1
-      - uses: rui314/setup-mold@7e4f20ad28a2e8ca6fd0892ccf72e2abb706b9c3 # v1
+      - uses: rui314/setup-mold@339e96b4ff1f3bd865856ba4cbbe8818a7acb038 # v1
       # Restores the Unit Tests lane's cache (_ci-rust.yml) read-only; this
       # lane never saves one of its own. The restore only hits while the cache
       # key matches: the same shared-key, and rust-cache's environment hash —
@@ -99,7 +99,7 @@ jobs:
         run: node scripts/flake-check.mjs rust --iterations=10 $SELECTED
       - name: Rust iteration reports
         if: ${{ !cancelled() }}
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: flake-rust
           path: test-results/flake
@@ -134,7 +134,7 @@ jobs:
         run: node scripts/flake-check.mjs node --iterations=10 $SELECTED
       - name: node:test iteration logs
         if: ${{ !cancelled() }}
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: flake-node
           path: test-results/flake
@@ -203,7 +203,7 @@ jobs:
         run: node scripts/flake-check.mjs playwright-summary desktop/playwright-report.json "Flake check (Playwright smoke, $SHARD/$SHARD_TOTAL)"
       - name: Playwright repetition artifacts
         if: ${{ !cancelled() }}
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: flake-playwright-${{ matrix.shard }}
           path: |
@@ -252,7 +252,7 @@ jobs:
         run: node scripts/flake-check.mjs dart --iterations=10 $SELECTED
       - name: Flutter iteration reports
         if: ${{ !cancelled() }}
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: flake-dart
           path: test-results/flake
diff --git a/scripts/flake-check.mjs b/scripts/flake-check.mjs
index e49d5c88e7..fcb1b8a27a 100644
--- a/scripts/flake-check.mjs
+++ b/scripts/flake-check.mjs
@@ -402,21 +402,23 @@ export function cratePackage(file) {
   return /^\[package\][\s\S]*?^name\s*=\s*"([^"]+)"/m.exec(manifest)[1];
 }
 
-// Cargo target flags building only the test binaries a file can be part of:
-// src/** is the lib (when the crate has one) or a bin, tests/<stem>.rs and
-// tests/<dir>/*.rs (with a main.rs) the integration test of that name. A
-// file placed by a custom `[[test]]` path builds every target instead.
+// Cargo target flags building only the test binaries a file can be part of,
+// one flag per entry so rustGroups can merge files' flags without splitting
+// `--test <name>`: src/** is the lib (when the crate has one) or a bin,
+// tests/<stem>.rs and tests/<dir>/*.rs (with a main.rs) the integration test
+// of that name. A file placed by a custom `[[test]]` path builds every target
+// instead.
 export function rustTarget(file) {
   const [, , kind, first, second] = file.split("/");
   if (kind === "src") {
     const lib =
       existsSync(`${crateDir(file)}/src/lib.rs`) ||
       /^\[lib\]/m.test(readFileSync(`${crateDir(file)}/Cargo.toml`, "utf8"));
-    return lib ? ["--lib", "--bins"] : ["--bins"];
+    return lib ? [["--lib"], ["--bins"]] : [["--bins"]];
   }
-  if (second === undefined) return ["--test", first.replace(/\.rs$/, "")];
+  if (second === undefined) return [["--test", first.replace(/\.rs$/, "")]];
   return existsSync(`${crateDir(file)}/tests/${first}/main.rs`)
-    ? ["--test", first]
+    ? [["--test", first]]
     : [];
 }
 
@@ -672,13 +674,12 @@ export function chooseRust(tests, candidates) {
   return [...chosen.values()];
 }
 
-// nextest has no repeat flag, so run the selection once per iteration under
-// the `flake` profile (.config/nextest.toml: no retries, JUnit per run), one
-// cargo invocation per package so each builds only the targets its files can
-// be in. The selection is listed first, by in-file path, and narrowed with
-// chooseRust to exact (binary, test) pairs; a selection listing no runnable
-// test is one of ignored or infrastructure-backed tests, not a failure.
-function repeatRust(entries, iterations) {
+// The repeat's cargo invocation per package: `-p <crate>` plus the target
+// flags of its selected files, each whole flag once (`--test codec --test
+// connection`; merging tokens instead gave `--test codec connection`, which
+// nextest reads as a test-name filter that matches nothing), and the tests
+// to list in those targets.
+export function rustGroups(entries) {
   const groups = new Map();
   for (const entry of entries) {
     const [, file, path] =
@@ -686,19 +687,35 @@ function repeatRust(entries, iterations) {
     if (!file)
       throw new Error(`rust entry must be <file>::<module::test>: ${entry}`);
     const crate = cratePackage(file);
-    const group = groups.get(crate) ?? { targets: new Set(), tests: [] };
+    const group = groups.get(crate) ?? { targets: new Map(), tests: [] };
     const targets = rustTarget(file);
     if (targets.length === 0) group.every = true;
-    for (const target of targets) group.targets.add(target);
+    for (const target of targets) group.targets.set(target.join(" "), target);
     group.tests.push({
       path,
       exact: [...rustModulePath(file), path].join("::"),
     });
     groups.set(crate, group);
   }
+  for (const [crate, group] of groups)
+    group.args = [
+      "-p",
+      crate,
+      ...(group.every ? [] : [...group.targets.values()].flat()),
+    ];
+  return groups;
+}
+
+// nextest has no repeat flag, so run the selection once per iteration under
+// the `flake` profile (.config/nextest.toml: no retries, JUnit per run), one
+// cargo invocation per package so each builds only the targets its files can
+// be in. The selection is listed first, by in-file path, and narrowed with
+// chooseRust to exact (binary, test) pairs; a selection listing no runnable
+// test is one of ignored or infrastructure-backed tests, not a failure.
+function repeatRust(entries, iterations) {
+  const groups = rustGroups(entries);
   const runs = [];
-  for (const [crate, group] of groups) {
-    group.args = ["-p", crate, ...(group.every ? [] : group.targets)];
+  for (const group of groups.values()) {
     const suffixes = [...new Set(group.tests.map(({ path }) => path))]
       .map((path) => `test(/(^|::)${path}$/)`)
       .join(" | ");
diff --git a/scripts/flake-check.test.mjs b/scripts/flake-check.test.mjs
index 21b4006ca2..fa868c993a 100644
--- a/scripts/flake-check.test.mjs
+++ b/scripts/flake-check.test.mjs
@@ -15,6 +15,7 @@ import {
   parseJunit,
   playwrightRepetitions,
   playwrightShards,
+  rustGroups,
   rustModulePath,
   rustTarget,
   rustTests,
@@ -261,14 +262,45 @@ test("same-named Rust tests in different modules are distinct, and a hunk select
   );
 });
 
-test("Rust files build only the targets they can be part of", () => {
+test("Rust files build only the targets they can be part of, merged per package one whole flag each", () => {
   for (const [file, flags] of [
-    ["crates/buzz-relay/src/api/mod.rs", ["--lib", "--bins"]],
-    ["crates/buzz-admin/src/main.rs", ["--bins"]],
-    ["crates/buzz-test-client/tests/e2e_relay.rs", ["--test", "e2e_relay"]],
+    ["crates/buzz-relay/src/api/mod.rs", [["--lib"], ["--bins"]]],
+    ["crates/buzz-admin/src/main.rs", [["--bins"]]],
+    ["crates/buzz-test-client/tests/e2e_relay.rs", [["--test", "e2e_relay"]]],
     ["crates/buzz-agent/tests/common/mod.rs", []],
   ])
     assert.deepEqual(rustTarget(file), flags, file);
+  // Two integration tests keep two `--test` flags: `--test codec connection`
+  // would make nextest filter on a test named "connection" and repeat nothing.
+  const args = (...entries) =>
+    [...rustGroups(entries).values()].map((group) => group.args);
+  assert.deepEqual(
+    args(
+      "crates/buzz-audio-client/tests/codec.rs::roundtrip",
+      "crates/buzz-audio-client/tests/connection.rs::connects",
+    ),
+    [["-p", "buzz-audio-client", "--test", "codec", "--test", "connection"]],
+  );
+  assert.deepEqual(
+    args(
+      "crates/buzz-audio-client/src/wire.rs::tests::frame",
+      "crates/buzz-audio-client/src/jitter.rs::tests::order",
+      "crates/buzz-audio-client/tests/codec.rs::roundtrip",
+    ),
+    [["-p", "buzz-audio-client", "--lib", "--bins", "--test", "codec"]],
+  );
+  // A custom-path file builds every target of its package; packages stay apart.
+  assert.deepEqual(
+    args(
+      "crates/buzz-agent/tests/regressions.rs::replay",
+      "crates/buzz-agent/tests/common/mod.rs::helper",
+      "crates/buzz-admin/src/main.rs::tests::parses",
+    ),
+    [
+      ["-p", "buzz-agent"],
+      ["-p", "buzz-admin", "--bins"],
+    ],
+  );
 });
 
 test("Rust selection: a hunk inside a test selects it, elsewhere selects every runnable test; ignored tests never run", () => {