nix cat/dump-path/key: stop progress bar before writeFull

These commands outputs data that may not end with a newline. This
causes problems when the progress bar redraws, as that completely
wipes the last line of output. As nix key generate-secret outputs
a single line of text with no output, it shows up entirely blank,
making it look like nothing happened.

Fixes: https://git.lix.systems/lix-project/lix/issues/320
Change-Id: I5ac706d71d839b6dfa760b60a351414cd96297cf

1 files changed, 5 insertions, 1 deletions

diff --git a/src/nix/cat.cc b/src/nix/cat.cc
index 60aa66ce0..678edd9a1 100644
--- a/src/nix/cat.cc
+++ b/src/nix/cat.cc
@@ -2,6 +2,7 @@
 #include "store-api.hh"
 #include "fs-accessor.hh"
 #include "nar-accessor.hh"
+#include "progress-bar.hh"
 
 using namespace nix;
 
@@ -17,7 +18,10 @@ struct MixCat : virtual Args
         if (st.type != FSAccessor::Type::tRegular)
             throw Error("path '%1%' is not a regular file", path);
 
-        writeFull(STDOUT_FILENO, accessor->readFile(path));
+        auto file = accessor->readFile(path);
+
+        stopProgressBar();
+        writeFull(STDOUT_FILENO, file);
     }
 };