testsuite: Improve error message in findDependencyInStore

haskell · Nov 14, 2023 · b519ddf · b519ddf
1 parent bccd4ec
commit b519ddf
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/cabal-testsuite/src/Test/Cabal/Prelude.hs b/cabal-testsuite/src/Test/Cabal/Prelude.hs
@@ -1156,5 +1156,7 @@ findDependencyInStore storeDir pkgName = do
             then filter (not . flip elem "aeiou") pkgName
                 -- simulates the way 'hashedInstalledPackageId' uses to compress package name
             else pkgName
-    let libDir = head $ filter (pkgName' `isPrefixOf`) packageDirs
+    let libDir = case filter (pkgName' `isPrefixOf`) packageDirs of
+                    [] -> error $ "Could not find " <> pkgName' <> " when searching for " <> pkgName' <> " in\n" <> show packageDirs
+                    (dir:_) -> dir
     pure (storeDir </> storeDirForGhcVersion </> libDir)