Use the provided OCaml version when a match is not found

src/version.ts

@@ -1,3 +1,4 @@
+import * as core from "@actions/core";
 import * as github from "@actions/github";
 import * as semver from "semver";
 
@@ -20,6 +21,7 @@ function unique(array: string[]) {
   return Array.from(new Set(array));
 }
 
+// Get all the OCaml releases on GitHub
 async function getAllCompilerVersions(): Promise<string[]> {
   const octokit = github.getOctokit(GITHUB_TOKEN);
   const releases = [];
@@ -42,13 +44,31 @@ async function getAllCompilerVersions(): Promise<string[]> {
   return versions;
 }
 
-export async function resolveVersion(semverVersion: string): Promise<string> {
+export async function resolveVersion(
+  semverVersionRange: string
+): Promise<string> {
   const compilerVersions = await getAllCompilerVersions();
-  const matchedFullCompilerVersions = compilerVersions
-    .filter((version) =>
-      semver.satisfies(version, semverVersion, { loose: true })
-    )
-    .sort((v1, v2) => semver.rcompare(v1, v2, { loose: true }));
-  const latestFullCompilerVersion = matchedFullCompilerVersions[0];
-  return latestFullCompilerVersion;
+  const latestFullCompilerVersion = semver.maxSatisfying(
+    compilerVersions,
+    semverVersionRange,
+    { loose: true }
+  );
+  if (latestFullCompilerVersion !== null) {
+    return latestFullCompilerVersion;
+  } else {
+    core.warning(
+      `Could not find an OCaml release on GitHub that matches the range ${semverVersionRange}.`
+    );
+    const cleanedFullCompilerVersion = semver.clean(semverVersionRange, {
+      loose: true,
+    });
+    if (cleanedFullCompilerVersion === null) {
+      throw new Error(`Failed to resolve version range ${semverVersionRange}.`);
+    } else {
+      core.warning(
+        `Proceed with the OCaml version ${cleanedFullCompilerVersion}.`
+      );
+      return cleanedFullCompilerVersion;
+    }
+  }
 }