Only fetch checksums for unknown wrapper versions (#292)

The checksum values for most wrapper versions are hard-coded into the
action. These known checksum values are first used for validation: only
if none of the known values work do we download checksums.

Previously, we blindly downloaded all of the checksum values in this
case: we now only download the checksums for versions that are not in
our "known" set.

Fixes #171

sources/src/wrapper-validation/checksums.ts

@@ -4,21 +4,27 @@ import fileWrapperChecksums from './wrapper-checksums.json'
 
 const httpc = new httpm.HttpClient('gradle/wrapper-validation-action', undefined, {allowRetries: true, maxRetries: 3})
 
-function getKnownValidChecksums(): Map<string, Set<string>> {
-    const versionsMap = new Map<string, Set<string>>()
-    for (const entry of fileWrapperChecksums) {
-        const checksum = entry.checksum
+export class WrapperChecksums {
+    checksums = new Map<string, Set<string>>()
+    versions = new Set<string>()
 
-        let versionNames = versionsMap.get(checksum)
-        if (versionNames === undefined) {
-            versionNames = new Set()
-            versionsMap.set(checksum, versionNames)
+    add(version: string, checksum: string): void {
+        if (this.checksums.has(checksum)) {
+            this.checksums.get(checksum)!.add(version)
+        } else {
+            this.checksums.set(checksum, new Set([version]))
         }
 
-        versionNames.add(entry.version)
+        this.versions.add(version)
     }
+}
 
-    return versionsMap
+function loadKnownChecksums(): WrapperChecksums {
+    const checksums = new WrapperChecksums()
+    for (const entry of fileWrapperChecksums) {
+        checksums.add(entry.version, entry.checksum)
+    }
+    return checksums
 }
 
 /**
@@ -26,9 +32,12 @@ function getKnownValidChecksums(): Map<string, Set<string>> {
  *
  * Maps from the checksum to the names of the Gradle versions whose wrapper has this checksum.
  */
-export const KNOWN_VALID_CHECKSUMS = getKnownValidChecksums()
+export const KNOWN_CHECKSUMS = loadKnownChecksums()
 
-export async function fetchValidChecksums(allowSnapshots: boolean): Promise<Set<string>> {
+export async function fetchUnknownChecksums(
+    allowSnapshots: boolean,
+    knownChecksums: WrapperChecksums
+): Promise<Set<string>> {
     const all = await httpGetJsonArray('https://services.gradle.org/versions/all')
     const withChecksum = all.filter(
         entry => typeof entry === 'object' && entry != null && entry.hasOwnProperty('wrapperChecksumUrl')
@@ -37,7 +46,11 @@ export async function fetchValidChecksums(allowSnapshots: boolean): Promise<Set<
         // eslint-disable-next-line @typescript-eslint/no-explicit-any
         (entry: any) => allowSnapshots || !entry.snapshot
     )
-    const checksumUrls = allowed.map(
+    const notKnown = allowed.filter(
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (entry: any) => !knownChecksums.versions.has(entry.version)
+    )
+    const checksumUrls = notKnown.map(
         // eslint-disable-next-line @typescript-eslint/no-explicit-any
         (entry: any) => entry.wrapperChecksumUrl as string
     )

sources/src/wrapper-validation/validate.ts

@@ -8,7 +8,7 @@ export async function findInvalidWrapperJars(
     minWrapperCount: number,
     allowSnapshots: boolean,
     allowedChecksums: string[],
-    knownValidChecksums: Map<string, Set<string>> = checksums.KNOWN_VALID_CHECKSUMS
+    knownValidChecksums: checksums.WrapperChecksums = checksums.KNOWN_CHECKSUMS
 ): Promise<ValidationResult> {
     const wrapperJars = await find.findWrapperJars(gitRepoRoot)
     const result = new ValidationResult([], [])
@@ -21,7 +21,7 @@ export async function findInvalidWrapperJars(
         const notYetValidatedWrappers = []
         for (const wrapperJar of wrapperJars) {
             const sha = await hash.sha256File(resolve(gitRepoRoot, wrapperJar))
-            if (allowedChecksums.includes(sha) || knownValidChecksums.has(sha)) {
+            if (allowedChecksums.includes(sha) || knownValidChecksums.checksums.has(sha)) {
                 result.valid.push(new WrapperJar(wrapperJar, sha))
             } else {
                 notYetValidatedWrappers.push(new WrapperJar(wrapperJar, sha))
@@ -31,7 +31,7 @@ export async function findInvalidWrapperJars(
         // Otherwise fall back to fetching checksums from Gradle API and compare against them
         if (notYetValidatedWrappers.length > 0) {
             result.fetchedChecksums = true
-            const fetchedValidChecksums = await checksums.fetchValidChecksums(allowSnapshots)
+            const fetchedValidChecksums = await checksums.fetchUnknownChecksums(allowSnapshots, knownValidChecksums)
 
             for (const wrapperJar of notYetValidatedWrappers) {
                 if (!fetchedValidChecksums.has(wrapperJar.checksum)) {