diff --git a/pkgs/build-support/fetchbzr/nix-prefetch-bzr b/pkgs/build-support/fetchbzr/nix-prefetch-bzr
index 9ff86c20ae3f..2f46819323f2 100755
--- a/pkgs/build-support/fetchbzr/nix-prefetch-bzr
+++ b/pkgs/build-support/fetchbzr/nix-prefetch-bzr
@@ -52,6 +52,8 @@ if test -z "$finalPath"; then
     # Perform the checkout.
     bzr -Ossl.cert_reqs=none export $revarg --format=dir "$tmpFile" "$url"
 
+    echo "bzr revision is $(bzr revno $revarg "$url")"
+
     # Compute the hash.
     hash=$(nix-hash --type $hashType $hashFormat $tmpFile)
     if ! test -n "$QUIET"; then echo "hash is $hash" >&2; fi
diff --git a/pkgs/build-support/fetchhg/nix-prefetch-hg b/pkgs/build-support/fetchhg/nix-prefetch-hg
index f1f648f4aeb8..075dbc9c367b 100755
--- a/pkgs/build-support/fetchhg/nix-prefetch-hg
+++ b/pkgs/build-support/fetchhg/nix-prefetch-hg
@@ -51,6 +51,7 @@ if test -z "$finalPath"; then
     hg archive -q -y -r "$rev" --cwd $tmpClone $tmpArchive
     rm -f $tmpArchive/.hg_archival.txt
 
+    echo "hg revision is $(cd $tmpClone; hg id -r "$rev" -i)"
 
     # Compute the hash.
     hash=$(nix-hash --type $hashType $hashFormat $tmpArchive)
diff --git a/pkgs/build-support/fetchsvn/nix-prefetch-svn b/pkgs/build-support/fetchsvn/nix-prefetch-svn
index 2858a0b01ab1..a2ee3ac6052f 100755
--- a/pkgs/build-support/fetchsvn/nix-prefetch-svn
+++ b/pkgs/build-support/fetchsvn/nix-prefetch-svn
@@ -56,6 +56,7 @@ if test -z "$finalPath"; then
     fi
 
     echo p | svn "$command" --quiet -r "$rev" "$url" "$tmpFile" >&2
+    echo "svn revision is $(svn info -r "$rev" "$url" | grep "Revision: " | cut -d' ' -f2)"
 
     # Compute the hash.
     hash=$(nix-hash --type $hashType $hashFormat $tmpFile)