Pass errors up the stack in CalculateWorld and InstallPackages

This problem was found in melange
 chainguard-dev/melange#1645

Any time a download failed, we did not communicate the error
up the stack.

Signed-off-by: Scott Moser <[email protected]>

pkg/apk/apk/implementation.go

@@ -524,9 +524,9 @@ func (a *APK) CalculateWorld(ctx context.Context, allpkgs []*RepositoryPackage)
 	resolved := make([]*APKResolved, len(allpkgs))
 
 	// A slice of pseudo-promises that get closed when expanded[i] is ready.
-	done := make([]chan struct{}, len(allpkgs))
+	done := make([]chan error, len(allpkgs))
 	for i := range allpkgs {
-		done[i] = make(chan struct{})
+		done[i] = make(chan error)
 	}
 
 	// Meanwhile, concurrently fetch and expand all our APKs.
@@ -537,18 +537,22 @@ func (a *APK) CalculateWorld(ctx context.Context, allpkgs []*RepositoryPackage)
 		g.Go(func() error {
 			r, err := a.FetchPackage(ctx, pkg)
 			if err != nil {
-				return fmt.Errorf("fetching %s: %w", pkg.Name, err)
+				err = fmt.Errorf("fetching %s: %w", pkg.Name, err)
+				done[i] <- err
+				return err
 			}
+
 			res, err := ResolveApk(ctx, r)
 			if err != nil {
-				return fmt.Errorf("resolving %s: %w", pkg.Name, err)
+				err = fmt.Errorf("resolving %s: %w", pkg.Name, err)
+				done[i] <- err
+				return err
 			}
 
 			res.Package = pkg
 			resolved[i] = res
 
-			close(done[i])
-
+			done[i] <- nil
 			return nil
 		})
 	}
@@ -645,9 +649,9 @@ func (a *APK) InstallPackages(ctx context.Context, sourceDateEpoch *time.Time, a
 	infos := make([]*Package, len(allpkgs))
 
 	// A slice of pseudo-promises that get closed when expanded[i] is ready.
-	done := make([]chan struct{}, len(allpkgs))
+	done := make([]chan error, len(allpkgs))
 	for i := range allpkgs {
-		done[i] = make(chan struct{})
+		done[i] = make(chan error)
 	}
 
 	// Kick off a goroutine that sequentially installs packages as they become ready.
@@ -660,7 +664,10 @@ func (a *APK) InstallPackages(ctx context.Context, sourceDateEpoch *time.Time, a
 			select {
 			case <-ctx.Done():
 				return ctx.Err()
-			case <-ch:
+			case err := <-ch:
+				if err != nil {
+					return err
+				}
 				exp := expanded[i]
 				pkg := allpkgs[i]
 
@@ -700,13 +707,13 @@ func (a *APK) InstallPackages(ctx context.Context, sourceDateEpoch *time.Time, a
 		g.Go(func() error {
 			exp, err := a.expandPackage(ctx, pkg)
 			if err != nil {
-				return fmt.Errorf("expanding %s: %w", pkg, err)
+				err = fmt.Errorf("expanding %s: %w", pkg, err)
+			} else {
+				expanded[i] = exp
 			}
 
-			expanded[i] = exp
-			close(done[i])
-
-			return nil
+			done[i] <- err
+			return err
 		})
 	}