Add a customized GitRepositoryError and funnel all Git operations through a method that throws one of those if the operation fails. This makes sure that Git failures clients can distinguish from other Process errors (so failure handling can be customized), and that they all have a location.

Author: abertelrud

Sources/PackageGraph/RepositoryPackageContainerProvider.swift

@@ -400,7 +400,7 @@ public class RepositoryPackageContainer: BasePackageContainer, CustomStringConve
             }.1
         } catch {
             // Examine the error to see if we can come up with a more informative and actionable error message.  We know that the revision is expected to be a branch name or a hash (tags are handled through a different code path).
-            if let gitInvocationError = error as? ProcessResult.Error, gitInvocationError.description.contains("Needed a single revision") {
+            if let error = error as? GitRepositoryError, error.description.contains("Needed a single revision") {
                 // It was a Git process invocation error.  Take a look at the repository to see if we can come up with a reasonable diagnostic.
                 if let rev = try? repository.resolveRevision(identifier: revision), repository.exists(revision: rev) {
                     // Revision does exist, so something else must be wrong.