diff --git a/analysis/dist/index.js b/analysis/dist/index.js
index 6f818443..f780f064 100644
--- a/analysis/dist/index.js
+++ b/analysis/dist/index.js
@@ -35972,7 +35972,7 @@ function createBuildTarget(output, filePath) {
 
 
 
-async function getOpamLocalPackages() {
+async function retrieveOpamLocalPackages() {
     const globber = await glob.create("*.opam");
     const fpaths = await globber.glob();
     return fpaths;
@@ -35983,7 +35983,7 @@ async function analysis() {
         url: "https://github.com/ocaml/setup-ocaml/tree/master/analysis",
         version: "0.0.0",
     });
-    const fpaths = await getOpamLocalPackages();
+    const fpaths = await retrieveOpamLocalPackages();
     for (const fpath of fpaths) {
         const temp = await promises_namespaceObject.mkdtemp(external_node_path_namespaceObject.join(external_node_os_namespaceObject.tmpdir(), "setup-ocaml-opam-tree-"));
         const tempJson = external_node_path_namespaceObject.join(temp, "tmp.json");
diff --git a/dist/index.js b/dist/index.js
index d2b6c251..8bca2ebe 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -137872,7 +137872,7 @@ var semver = __nccwpck_require__(90084);
 function isSemverValidRange(semverVersion) {
     return semver.validRange(semverVersion, { loose: true }) !== null;
 }
-async function getAllCompilerVersions() {
+async function retrieveAllCompilerVersions() {
     const octokit = lib_github.getOctokit(constants_GITHUB_TOKEN);
     const { data: packages } = await octokit.rest.repos.getContent({
         owner: "ocaml",
@@ -137900,7 +137900,7 @@ async function getAllCompilerVersions() {
     return [...versions];
 }
 async function resolveVersion(semverVersion) {
-    const compilerVersions = await getAllCompilerVersions();
+    const compilerVersions = await retrieveAllCompilerVersions();
     const matchedFullCompilerVersion = semver.maxSatisfying(compilerVersions, semverVersion, { loose: true });
     if (matchedFullCompilerVersion === null) {
         throw new Error(`No OCaml base compiler packages matched the version ${semverVersion} in the opam-repository.`);
@@ -138041,7 +138041,7 @@ var tool_cache = __nccwpck_require__(60532);
 
 
 
-async function checkInstallability(packageName) {
+async function checkAptInstallability(packageName) {
     const output = await (0,lib_exec.getExecOutput)("sudo", [
         "apt-cache",
         "search",
@@ -138050,17 +138050,24 @@ async function checkInstallability(packageName) {
     ]);
     return output.stdout.length !== 0;
 }
+async function retrieveInstallableOptionalDependencies(optionalDependencies) {
+    switch (PLATFORM) {
+        case "linux": {
+            return optionalDependencies.filter(async (dep) => await checkAptInstallability(dep));
+        }
+        default: {
+            return [];
+        }
+    }
+}
 async function installUnixSystemPackages() {
     const isGitHubRunner = external_node_process_.env.GITHUB_ACTIONS === "true";
+    const optionalDependencies = await retrieveInstallableOptionalDependencies([
+        "darcs",
+        "mercurial",
+    ]);
     if (isGitHubRunner) {
         if (PLATFORM === "linux") {
-            const darcs = await (async () => {
-                const installability = await checkInstallability("darcs");
-                if (installability) {
-                    return ["darcs"];
-                }
-                return [];
-            })();
             await (0,lib_exec.exec)("sudo", [
                 "apt-get",
                 "--yes",
@@ -138068,10 +138075,9 @@ async function installUnixSystemPackages() {
                 "bubblewrap",
                 "g++-multilib",
                 "gcc-multilib",
-                "mercurial",
                 "musl-tools",
                 "rsync",
-                ...darcs,
+                ...optionalDependencies,
             ]);
         }
         else if (PLATFORM === "macos") {
@@ -138101,7 +138107,7 @@ async function updateUnixPackageIndexFiles() {
 
 
 
-async function getLatestOpamRelease() {
+async function retrieveLatestOpamRelease() {
     const semverRange = ALLOW_PRERELEASE_OPAM ? "*" : "<2.3.0";
     const octokit = lib_github.getOctokit(constants_GITHUB_TOKEN);
     const { data: releases } = await octokit.rest.repos.listReleases({
@@ -138134,7 +138140,7 @@ async function getLatestOpamRelease() {
 }
 async function acquireOpam() {
     await lib_core.group("Install opam", async () => {
-        const { version, browserDownloadUrl } = await getLatestOpamRelease();
+        const { version, browserDownloadUrl } = await retrieveLatestOpamRelease();
         const cachedPath = tool_cache.find("opam", version, ARCHITECTURE);
         const opam = PLATFORM !== "windows" ? "opam" : "opam.exe";
         if (cachedPath === "") {
@@ -156704,7 +156710,7 @@ async function fromURL(url, options = {}) {
 function createHttpClient() {
     return new http_client_lib.HttpClient("OCamlBot (+https://github.com/ocaml/setup-ocaml)", [], { allowRetries: true, maxRetries: 5 });
 }
-async function getCygwinVersion() {
+async function retrieveCygwinVersion() {
     const httpClient = createHttpClient();
     const response = await httpClient.get("https://www.cygwin.com");
     const body = await response.readBody();
@@ -156749,7 +156755,7 @@ async function setGitToIgnoreCygwinLocalPackageDirectory() {
 async function setupCygwin() {
     await lib_core.group("Prepare the Cygwin environment", async () => {
         await setGitToIgnoreCygwinLocalPackageDirectory();
-        const version = await getCygwinVersion();
+        const version = await retrieveCygwinVersion();
         const cachedPath = tool_cache.find("cygwin", version, "x86_64");
         if (cachedPath === "") {
             const downloadedPath = await tool_cache.downloadTool("https://cygwin.com/setup-x86_64.exe");
@@ -156797,7 +156803,7 @@ async function setupCygwin() {
 
 
 async function composeCygwinCacheKeys() {
-    const cygwinVersion = await getCygwinVersion();
+    const cygwinVersion = await retrieveCygwinVersion();
     const key = `${CACHE_PREFIX}-setup-ocaml-cygwin-${cygwinVersion}`;
     const restoreKeys = [key];
     return { key, restoreKeys };
@@ -156817,7 +156823,7 @@ async function composeDuneCacheKeys() {
     return { key, restoreKeys };
 }
 async function composeOpamCacheKeys() {
-    const { version: opamVersion } = await getLatestOpamRelease();
+    const { version: opamVersion } = await retrieveLatestOpamRelease();
     const sandbox = OPAM_DISABLE_SANDBOXING ? "nosandbox" : "sandbox";
     const ocamlCompiler = await RESOLVED_COMPILER;
     const repositoryUrls = OPAM_REPOSITORIES.map(([_, value]) => value).join(",");
@@ -156993,7 +156999,7 @@ var glob = __nccwpck_require__(72922);
 ;// CONCATENATED MODULE: ./src/packages.ts
 
 
-async function getOpamLocalPackages() {
+async function retrieveOpamLocalPackages() {
     const globber = await glob.create(OPAM_LOCAL_PACKAGES);
     const fpaths = await globber.glob();
     return fpaths;
@@ -157063,7 +157069,7 @@ async function installer() {
         lib_core.exportVariable("DUNE_CACHE_TRANSPORT", "direct");
     }
     lib_core.exportVariable("CLICOLOR_FORCE", "1");
-    const fnames = await getOpamLocalPackages();
+    const fnames = await retrieveOpamLocalPackages();
     if (fnames.length > 0) {
         if (OPAM_PIN) {
             await pin(fnames);
diff --git a/dist/post/index.js b/dist/post/index.js
index 7caf9cd5..4634e2b2 100644
--- a/dist/post/index.js
+++ b/dist/post/index.js
@@ -102957,7 +102957,7 @@ var semver = __nccwpck_require__(84);
 function isSemverValidRange(semverVersion) {
     return semver.validRange(semverVersion, { loose: true }) !== null;
 }
-async function getAllCompilerVersions() {
+async function retrieveAllCompilerVersions() {
     const octokit = lib_github.getOctokit(GITHUB_TOKEN);
     const { data: packages } = await octokit.rest.repos.getContent({
         owner: "ocaml",
@@ -102985,7 +102985,7 @@ async function getAllCompilerVersions() {
     return [...versions];
 }
 async function resolveVersion(semverVersion) {
-    const compilerVersions = await getAllCompilerVersions();
+    const compilerVersions = await retrieveAllCompilerVersions();
     const matchedFullCompilerVersion = semver.maxSatisfying(compilerVersions, semverVersion, { loose: true });
     if (matchedFullCompilerVersion === null) {
         throw new Error(`No OCaml base compiler packages matched the version ${semverVersion} in the opam-repository.`);
@@ -103130,7 +103130,7 @@ const constants_RESOLVED_COMPILER = (async () => {
 
 
 async function composeCygwinCacheKeys() {
-    const cygwinVersion = await getCygwinVersion();
+    const cygwinVersion = await retrieveCygwinVersion();
     const key = `${CACHE_PREFIX}-setup-ocaml-cygwin-${cygwinVersion}`;
     const restoreKeys = [key];
     return { key, restoreKeys };
@@ -103150,7 +103150,7 @@ async function composeDuneCacheKeys() {
     return { key, restoreKeys };
 }
 async function composeOpamCacheKeys() {
-    const { version: opamVersion } = await getLatestOpamRelease();
+    const { version: opamVersion } = await retrieveLatestOpamRelease();
     const sandbox = OPAM_DISABLE_SANDBOXING ? "nosandbox" : "sandbox";
     const ocamlCompiler = await RESOLVED_COMPILER;
     const repositoryUrls = OPAM_REPOSITORIES.map(([_, value]) => value).join(",");
diff --git a/lint-fmt/dist/index.js b/lint-fmt/dist/index.js
index ee39879a..630843b5 100644
--- a/lint-fmt/dist/index.js
+++ b/lint-fmt/dist/index.js
@@ -27457,7 +27457,7 @@ async function parse() {
         return;
     }
 }
-async function getOcamlformatVersion() {
+async function retrieveOcamlformatVersion() {
     const config = await parse();
     if (config === undefined) {
         core.warning(".ocamlformat file is not found");
@@ -27492,7 +27492,7 @@ async function installDune() {
 
 async function run() {
     try {
-        const version = await getOcamlformatVersion();
+        const version = await retrieveOcamlformatVersion();
         if (version) {
             await installOcamlformat(version);
         }
diff --git a/packages/analysis/src/analysis.ts b/packages/analysis/src/analysis.ts
index 0bed6235..27bdae6a 100644
--- a/packages/analysis/src/analysis.ts
+++ b/packages/analysis/src/analysis.ts
@@ -11,7 +11,7 @@ import {
 import type { Output } from "./opam-detector.js";
 import { createBuildTarget } from "./opam-detector.js";
 
-async function getOpamLocalPackages() {
+async function retrieveOpamLocalPackages() {
   const globber = await glob.create("*.opam");
   const fpaths = await globber.glob();
   return fpaths;
@@ -23,7 +23,7 @@ export async function analysis() {
     url: "https://github.com/ocaml/setup-ocaml/tree/master/analysis",
     version: "0.0.0",
   });
-  const fpaths = await getOpamLocalPackages();
+  const fpaths = await retrieveOpamLocalPackages();
   for (const fpath of fpaths) {
     const temp = await fs.mkdtemp(
       path.join(os.tmpdir(), "setup-ocaml-opam-tree-"),
diff --git a/packages/lint-fmt/src/index.ts b/packages/lint-fmt/src/index.ts
index aa84f51b..656f22b6 100644
--- a/packages/lint-fmt/src/index.ts
+++ b/packages/lint-fmt/src/index.ts
@@ -1,12 +1,12 @@
 import * as process from "node:process";
 import * as core from "@actions/core";
 import { checkFmt } from "./lint.js";
-import { getOcamlformatVersion } from "./ocamlformat.js";
+import { retrieveOcamlformatVersion } from "./ocamlformat.js";
 import { installDune, installOcamlformat } from "./opam.js";
 
 async function run() {
   try {
-    const version = await getOcamlformatVersion();
+    const version = await retrieveOcamlformatVersion();
     if (version) {
       await installOcamlformat(version);
     }
diff --git a/packages/lint-fmt/src/ocamlformat.ts b/packages/lint-fmt/src/ocamlformat.ts
index 2d6e98d6..019aec90 100644
--- a/packages/lint-fmt/src/ocamlformat.ts
+++ b/packages/lint-fmt/src/ocamlformat.ts
@@ -22,7 +22,7 @@ async function parse() {
   }
 }
 
-export async function getOcamlformatVersion() {
+export async function retrieveOcamlformatVersion() {
   const config = await parse();
   if (config === undefined) {
     core.warning(".ocamlformat file is not found");
diff --git a/packages/setup-ocaml/src/cache.ts b/packages/setup-ocaml/src/cache.ts
index 7904c582..c5d10b20 100644
--- a/packages/setup-ocaml/src/cache.ts
+++ b/packages/setup-ocaml/src/cache.ts
@@ -18,11 +18,11 @@ import {
   PLATFORM,
   RESOLVED_COMPILER,
 } from "./constants.js";
-import { getLatestOpamRelease } from "./opam.js";
-import { getCygwinVersion } from "./windows.js";
+import { retrieveLatestOpamRelease } from "./opam.js";
+import { retrieveCygwinVersion } from "./windows.js";
 
 async function composeCygwinCacheKeys() {
-  const cygwinVersion = await getCygwinVersion();
+  const cygwinVersion = await retrieveCygwinVersion();
   const key = `${CACHE_PREFIX}-setup-ocaml-cygwin-${cygwinVersion}`;
   const restoreKeys = [key];
   return { key, restoreKeys };
@@ -44,7 +44,7 @@ async function composeDuneCacheKeys() {
 }
 
 async function composeOpamCacheKeys() {
-  const { version: opamVersion } = await getLatestOpamRelease();
+  const { version: opamVersion } = await retrieveLatestOpamRelease();
   const sandbox = OPAM_DISABLE_SANDBOXING ? "nosandbox" : "sandbox";
   const ocamlCompiler = await RESOLVED_COMPILER;
   const repositoryUrls = OPAM_REPOSITORIES.map(([_, value]) => value).join(",");
diff --git a/packages/setup-ocaml/src/installer.ts b/packages/setup-ocaml/src/installer.ts
index 9f38d94a..26f65490 100644
--- a/packages/setup-ocaml/src/installer.ts
+++ b/packages/setup-ocaml/src/installer.ts
@@ -26,7 +26,7 @@ import {
   repositoryRemoveAll,
   setupOpam,
 } from "./opam.js";
-import { getOpamLocalPackages } from "./packages.js";
+import { retrieveOpamLocalPackages } from "./packages.js";
 import { setupCygwin } from "./windows.js";
 
 export async function installer() {
@@ -85,7 +85,7 @@ export async function installer() {
     core.exportVariable("DUNE_CACHE_TRANSPORT", "direct");
   }
   core.exportVariable("CLICOLOR_FORCE", "1");
-  const fnames = await getOpamLocalPackages();
+  const fnames = await retrieveOpamLocalPackages();
   if (fnames.length > 0) {
     if (OPAM_PIN) {
       await pin(fnames);
diff --git a/packages/setup-ocaml/src/opam.ts b/packages/setup-ocaml/src/opam.ts
index d620d272..6f1bfc6d 100644
--- a/packages/setup-ocaml/src/opam.ts
+++ b/packages/setup-ocaml/src/opam.ts
@@ -18,7 +18,7 @@ import {
   updateUnixPackageIndexFiles,
 } from "./unix.js";
 
-export async function getLatestOpamRelease() {
+export async function retrieveLatestOpamRelease() {
   const semverRange = ALLOW_PRERELEASE_OPAM ? "*" : "<2.3.0";
   const octokit = github.getOctokit(GITHUB_TOKEN);
   const { data: releases } = await octokit.rest.repos.listReleases({
@@ -62,7 +62,7 @@ export async function getLatestOpamRelease() {
 
 async function acquireOpam() {
   await core.group("Install opam", async () => {
-    const { version, browserDownloadUrl } = await getLatestOpamRelease();
+    const { version, browserDownloadUrl } = await retrieveLatestOpamRelease();
     const cachedPath = toolCache.find("opam", version, ARCHITECTURE);
     const opam = PLATFORM !== "windows" ? "opam" : "opam.exe";
     if (cachedPath === "") {
diff --git a/packages/setup-ocaml/src/packages.ts b/packages/setup-ocaml/src/packages.ts
index a3e1ba1e..5070d147 100644
--- a/packages/setup-ocaml/src/packages.ts
+++ b/packages/setup-ocaml/src/packages.ts
@@ -1,7 +1,7 @@
 import * as glob from "@actions/glob";
 import { OPAM_LOCAL_PACKAGES } from "./constants.js";
 
-export async function getOpamLocalPackages() {
+export async function retrieveOpamLocalPackages() {
   const globber = await glob.create(OPAM_LOCAL_PACKAGES);
   const fpaths = await globber.glob();
   return fpaths;
diff --git a/packages/setup-ocaml/src/unix.ts b/packages/setup-ocaml/src/unix.ts
index 8b45c0e8..8a7a1d9f 100644
--- a/packages/setup-ocaml/src/unix.ts
+++ b/packages/setup-ocaml/src/unix.ts
@@ -2,7 +2,7 @@ import * as process from "node:process";
 import { exec, getExecOutput } from "@actions/exec";
 import { PLATFORM } from "./constants.js";
 
-async function checkInstallability(packageName: string) {
+async function checkAptInstallability(packageName: string) {
   const output = await getExecOutput("sudo", [
     "apt-cache",
     "search",
@@ -12,17 +12,29 @@ async function checkInstallability(packageName: string) {
   return output.stdout.length !== 0;
 }
 
+async function retrieveInstallableOptionalDependencies(
+  optionalDependencies: string[],
+) {
+  switch (PLATFORM) {
+    case "linux": {
+      return optionalDependencies.filter(
+        async (dep) => await checkAptInstallability(dep),
+      );
+    }
+    default: {
+      return [];
+    }
+  }
+}
+
 export async function installUnixSystemPackages() {
   const isGitHubRunner = process.env.GITHUB_ACTIONS === "true";
+  const optionalDependencies = await retrieveInstallableOptionalDependencies([
+    "darcs",
+    "mercurial",
+  ]);
   if (isGitHubRunner) {
     if (PLATFORM === "linux") {
-      const darcs = await (async () => {
-        const installability = await checkInstallability("darcs");
-        if (installability) {
-          return ["darcs"];
-        }
-        return [];
-      })();
       await exec("sudo", [
         "apt-get",
         "--yes",
@@ -30,10 +42,9 @@ export async function installUnixSystemPackages() {
         "bubblewrap",
         "g++-multilib",
         "gcc-multilib",
-        "mercurial",
         "musl-tools",
         "rsync",
-        ...darcs,
+        ...optionalDependencies,
       ]);
     } else if (PLATFORM === "macos") {
       await exec("brew", ["install", "darcs", "gpatch", "mercurial"]);
diff --git a/packages/setup-ocaml/src/version.ts b/packages/setup-ocaml/src/version.ts
index 39b42e46..dc03875d 100644
--- a/packages/setup-ocaml/src/version.ts
+++ b/packages/setup-ocaml/src/version.ts
@@ -7,7 +7,7 @@ function isSemverValidRange(semverVersion: string) {
   return semver.validRange(semverVersion, { loose: true }) !== null;
 }
 
-async function getAllCompilerVersions() {
+async function retrieveAllCompilerVersions() {
   const octokit = github.getOctokit(GITHUB_TOKEN);
   const { data: packages } = await octokit.rest.repos.getContent({
     owner: "ocaml",
@@ -37,7 +37,7 @@ async function getAllCompilerVersions() {
 }
 
 async function resolveVersion(semverVersion: string) {
-  const compilerVersions = await getAllCompilerVersions();
+  const compilerVersions = await retrieveAllCompilerVersions();
   const matchedFullCompilerVersion = semver.maxSatisfying(
     compilerVersions,
     semverVersion,
diff --git a/packages/setup-ocaml/src/windows.ts b/packages/setup-ocaml/src/windows.ts
index 42444668..0f046594 100644
--- a/packages/setup-ocaml/src/windows.ts
+++ b/packages/setup-ocaml/src/windows.ts
@@ -22,7 +22,7 @@ function createHttpClient() {
   );
 }
 
-export async function getCygwinVersion() {
+export async function retrieveCygwinVersion() {
   const httpClient = createHttpClient();
   const response = await httpClient.get("https://www.cygwin.com");
   const body = await response.readBody();
@@ -71,7 +71,7 @@ async function setGitToIgnoreCygwinLocalPackageDirectory() {
 export async function setupCygwin() {
   await core.group("Prepare the Cygwin environment", async () => {
     await setGitToIgnoreCygwinLocalPackageDirectory();
-    const version = await getCygwinVersion();
+    const version = await retrieveCygwinVersion();
     const cachedPath = toolCache.find("cygwin", version, "x86_64");
     if (cachedPath === "") {
       const downloadedPath = await toolCache.downloadTool(