@@ -75,5 +75,6 @@
   "eslint.useESLintClass": true,
   "yaml.schemas": {
     "https://json.schemastore.org/container-structure-test.json": "/dev/docker/ci/tests/*.yml"
-  }
+  },
+  "js/ts.tsdk.path": "node_modules/typescript/lib"
 }
@@ -3,6 +3,7 @@ FROM aminya/setup-cpp-ubuntu:latest AS setup-cpp-ubuntu-mingw
 # install mingw/powershell
 RUN setup-cpp \
     --compiler mingw \
+    --gcc true \
     --powershell true && \
 # cleanup
     apt-get clean autoclean && \
 
@@ -17,6 +17,7 @@ RUN apt-get update -qq && \
         --autoreconf true \
         --nala true \
         --compiler mingw \
+        --gcc true \
         --cmake true \
         --ninja true \
         --task true \
 
@@ -0,0 +1,49 @@
+import { execaSync } from "execa"
+
+import { getAptEnv } from "../src/apt-env.js"
+import { hasAptGet } from "../src/get-apt.js"
+import { filterAndQualifyAptPackages } from "../src/qualify-install.js"
+
+function indexedGccVariants() {
+  try {
+    const { stdout } = execaSync("apt-cache", ["search", "--names-only", "^gcc-[0-9]+$"], {
+      env: getAptEnv("apt-get"),
+      stdio: "pipe",
+    })
+    return stdout.split("\n")
+      .map((line) => line.trim().split(/\s+/u)[0])
+      .filter((name): name is string => name !== undefined && /^gcc-\d+$/u.test(name))
+      .sort((first, second) => {
+        const firstVersion = Number.parseInt(first.slice("gcc-".length), 10)
+        const secondVersion = Number.parseInt(second.slice("gcc-".length), 10)
+        return secondVersion - firstVersion
+      })
+  } catch {
+    return []
+  }
+}
+
+describe("filterAndQualifyAptPackages", () => {
+  if (!hasAptGet()) {
+    test.skip("filters installed packages", () => {})
+    return
+  }
+
+  it("filters an installed package when upgrade is disabled", async () => {
+    await expect(filterAndQualifyAptPackages([{ name: "apt", upgrade: false }])).resolves.toEqual([])
+  })
+
+  it("retains an installed package when upgrade is requested", async () => {
+    await expect(filterAndQualifyAptPackages([{ name: "apt", upgrade: true }])).resolves.toEqual(["apt"])
+  })
+
+  const gccVariants = indexedGccVariants()
+  if (gccVariants.length === 0) {
+    test.skip("resolves the highest indexed gcc-N package", () => {})
+    return
+  }
+
+  it("resolves an unversioned package to its highest indexed numeric variant", async () => {
+    await expect(filterAndQualifyAptPackages([{ name: "gcc" }])).resolves.toEqual([gccVariants[0]])
+  })
+})
@@ -30,6 +30,11 @@ export type AptPackage = {
   name: string
   /** The version of the package (optional) */
   version?: string
+  /**
+   * Whether to allow apt to upgrade the latest package available in the default repositories.
+   * This would could do a major upgrade for unversioned meta packages (e.g. gcc) or minor upgrade for versioned packages (e.g. gcc-9)
+   */
+  upgrade?: boolean
   /** The repository to add before installing the package (optional) */
   repository?: string
   /** The key to add before installing the package (optional) */
 
@@ -28,13 +28,15 @@ export async function filterAndQualifyAptPackages(packages: AptPackage[], apt: s
 /**
  * Qualify the package into full package name/version.
  * If the package is not installed, return the full package name/version.
- * If the package is already installed, return undefined
+ * If the package is already installed and upgrade is not requested, return undefined
  */
 export async function qualifiedNeededAptPackage(pack: AptPackage, apt: string = getApt()) {
+  // By default, leave the package in the install list so apt can select the candidate.
+  const upgrade = pack.upgrade ?? true
   // Qualify the package into full package name/version
   const qualified = await getAptArg(apt, pack)
-  // filter out the package that are already installed
-  return (await isAptPackInstalled(qualified)) ? undefined : qualified
+  // Filter out packages that are already installed unless they should be upgraded.
+  return (await isAptPackInstalled(qualified)) && !upgrade ? undefined : qualified
 }
 
 async function aptPackageType(
@@ -118,7 +120,14 @@ async function aptCacheShowHasPackage(apt: string, arg: string) {
 }
 
 async function getAptArg(apt: string, pack: AptPackage) {
-  const { name, version, fallBackToLatest = false } = pack
+  const { name, version, upgrade = true, fallBackToLatest = false } = pack
+
+  if ((version === undefined || version === "") && upgrade) {
+    const numericVariant = await findHighestNumericAptPackage(apt, name)
+    if (numericVariant !== undefined) {
+      return numericVariant
+    }
+  }
 
   const package_type = await aptPackageType(apt, name, version, fallBackToLatest)
   switch (package_type) {
@@ -133,3 +142,24 @@ async function getAptArg(apt: string, pack: AptPackage) {
       throw new Error(`Could not find package '${name}' ${version ?? "with unspecified version"}`)
   }
 }
+
+async function findHighestNumericAptPackage(apt: string, name: string) {
+  const packageNamePattern = new RegExp(`^${escapeRegex(name)}-([0-9]+)$`, "u")
+
+  try {
+    const { stdout } = await execa("apt-cache", [
+      "search",
+      "--names-only",
+      `^${escapeRegex(name)}-[0-9]+$`,
+    ], { env: getAptEnv(apt), stdio: "pipe" })
+    const candidates = stdout.split("\n").flatMap((line) => {
+      const packageName: string | undefined = line.trim().split(/\s+/u)[0]
+      const match = packageName.match(packageNamePattern)
+      return match === null ? [] : [{ packageName, version: Number.parseInt(match[1], 10) }]
+    })
+
+    return candidates.sort((first, second) => second.version - first.version)[0]?.packageName
+  } catch {
+    return undefined
+  }
+}
Original file line number	Diff line number	Diff line change
`@@ -75,5 +75,6 @@`
`75`	`75`	`"eslint.useESLintClass": true,`
`76`	`76`	`"yaml.schemas": {`
`77`	`77`	`"https://json.schemastore.org/container-structure-test.json": "/dev/docker/ci/tests/*.yml"`
`78`		`- }`
	`78`	`+ },`
	`79`	`+ "js/ts.tsdk.path": "node_modules/typescript/lib"`
`79`	`80`	`}`