mkdir -p /var/cache/melange even if --cache-dir isn't found

Signed-off-by: Jason Hall <[email protected]>

pipelines/fetch.yaml

@@ -37,6 +37,7 @@ pipeline:
 
       bn=$(basename ${{inputs.uri}})
 
+      ls /var/cache/melange ## TODO(jason): Remove this; this just tests that the dir exists.
       if [ ! "${{inputs.expected-sha256}}" == "" ]; then
         fn="/var/cache/melange/sha256:${{inputs.expected-sha256}}"
         printf "Looking for $fn in cache"

pkg/build/build.go

@@ -620,8 +620,13 @@ func (ctx *Context) PopulateCache() error {
 
 	fsys := apkofs.DirFS(ctx.CacheDir)
 
+	// mkdir /var/cache/melange
+	if err := os.MkdirAll("/var/cache/melange", 0o755); err != nil {
+		return err
+	}
+
+	// --cache-dir doesn't exist, nothing to do.
 	if _, err := fs.Stat(fsys, "."); errors.Is(err, fs.ErrNotExist) {
-		// --cache-dir doesn't exist, skip it.
 		return nil
 	}