Add better comments

packages/cache/src/cache.ts

@@ -96,8 +96,7 @@ export async function restoreCache(
       compressionMethod
     })
     if (!cacheEntry?.archiveLocation) {
-      // This is to support the old cache entry created
-      // by the old version of the cache action on windows.
+      // This is to support the old cache entry created by gzip on windows.
       if (
         process.platform === 'win32' &&
         compressionMethod !== CompressionMethod.Gzip
@@ -111,7 +110,7 @@ export async function restoreCache(
         }
 
         core.debug(
-          "Couldn't find cache entry with zstd compression, falling back to gzip compression"
+          "Couldn't find cache entry with zstd compression, falling back to gzip compression."
         )
       } else {
         // Cache not found

packages/cache/src/internal/cacheHttpClient.ts

@@ -104,6 +104,7 @@ export async function getCacheEntry(
     httpClient.getJson<ArtifactCacheEntry>(getCacheApiUrl(resource))
   )
   if (response.statusCode === 204) {
+    // Cache not found
     return null
   }
   if (!isSuccessStatusCode(response.statusCode)) {
@@ -113,6 +114,7 @@ export async function getCacheEntry(
   const cacheResult = response.result
   const cacheDownloadUrl = cacheResult?.archiveLocation
   if (!cacheDownloadUrl) {
+    // Cache achiveLocation not found
     throw new Error('Cache not found.')
   }
   core.setSecret(cacheDownloadUrl)

packages/cache/src/internal/tar.ts

@@ -14,7 +14,7 @@ import {
 
 const IS_WINDOWS = process.platform === 'win32'
 
-// Function also mutates the args array. For non-mutation call with passing an empty array.
+// Returns tar path and type: BSD or GNU
 async function getTarPath(): Promise<ArchiveTool> {
   switch (process.platform) {
     case 'win32': {
@@ -43,6 +43,7 @@ async function getTarPath(): Promise<ArchiveTool> {
     default:
       break
   }
+  // Default assumption is GNU tar is present in path
   return <ArchiveTool>{
     path: await io.which('tar', true),
     type: ArchiveToolType.GNU
@@ -60,6 +61,7 @@ async function getTarArgs(
   const cacheFileName = utils.getCacheFileName(compressionMethod)
   const tarFile = 'cache.tar'
   const workingDirectory = getWorkingDirectory()
+  // Speficic args for BSD tar on windows for workaround
   const BSD_TAR_ZSTD =
     tarPath.type === ArchiveToolType.BSD &&
     compressionMethod !== CompressionMethod.Gzip &&
@@ -122,6 +124,7 @@ async function getTarArgs(
   return args
 }
 
+// Returns commands to run tar and compression program
 async function getCommands(
   compressionMethod: CompressionMethod,
   type: string,
@@ -201,6 +204,7 @@ async function getDecompressionProgram(
   }
 }
 
+// Used for creating the archive
 // -T#: Compress using # working thread. If # is 0, attempt to detect and use the number of physical CPU cores.
 // zstdmt is equivalent to 'zstd -T0'
 // --long=#: Enables long distance matching with # bits. Maximum is 30 (1GB) on 32-bit OS and 31 (2GB) on 64-bit.
@@ -240,6 +244,7 @@ async function getCompressionProgram(
   }
 }
 
+// Executes all commands as separate processes
 async function execCommands(commands: string[], cwd?: string): Promise<void> {
   for (const command of commands) {
     try {
@@ -252,6 +257,7 @@ async function execCommands(commands: string[], cwd?: string): Promise<void> {
   }
 }
 
+// List the contents of a tar
 export async function listTar(
   archivePath: string,
   compressionMethod: CompressionMethod
@@ -260,6 +266,7 @@ export async function listTar(
   await execCommands(commands)
 }
 
+// Extract a tar
 export async function extractTar(
   archivePath: string,
   compressionMethod: CompressionMethod
@@ -271,6 +278,7 @@ export async function extractTar(
   await execCommands(commands)
 }
 
+// Create a tar
 export async function createTar(
   archiveFolder: string,
   sourceDirectories: string[],