internal/fetchdatasource: GetUnitMeta returns NotFound on missing package

If a module exists but the package path is not in it, return NotFound.

For golang/go#47780

Change-Id: If3a6602df4b99c8470020e8538e01c685880d86d
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/345251
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Reviewed-by: Julie Qiu <julie@golang.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/internal/fetchdatasource/fetchdatasource.go b/internal/fetchdatasource/fetchdatasource.go
index 69f803eb..fe2eacca 100644
--- a/internal/fetchdatasource/fetchdatasource.go
+++ b/internal/fetchdatasource/fetchdatasource.go
@@ -181,10 +181,12 @@ func (ds *FetchDataSource) GetUnitMeta(ctx context.Context, path, requestedModul
 		Path:       path,
 		ModuleInfo: module.ModuleInfo,
 	}
-	if u := findUnit(module, path); u != nil {
-		um.Name = u.Name
-		um.IsRedistributable = u.IsRedistributable
+	u := findUnit(module, path)
+	if u == nil {
+		return nil, derrors.NotFound
 	}
+	um.Name = u.Name
+	um.IsRedistributable = u.IsRedistributable
 	return um, nil
 }