nailing-cargo: Update mode: cope if Cargo.lock starts absent

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/nailing-cargo b/nailing-cargo
index 36d652eaf6a1facb26c634bfd0d6cd2e7df9199e..0e351a8267ccee231a5ee6f7a0e1987c83d3e3be 100755 (executable)
--- a/nailing-cargo
+++ b/nailing-cargo
@@ -405,14 +405,14 @@ sub oot_massage_cmdline () {
     $pre =  <<'END';
         cd "$1"; shift;
         mkdir -p -- "$1"; cd "$1"; shift;
-        cp -- "$1"/Cargo.toml .;
+        cp -- "$1"/Cargo.toml
 END
-    $pre .= <<'END';
-        cp -- "$1"/Cargo.lock .;
-END
-    $pre .= <<'ENDLK';
-        cp -- "$1"/Cargo.lock .;
+    $pre .= <<'ENDLK' if stat_exists 'Cargo.lock', 'working cargo lockfile';
+              "$1"/Cargo.lock
 ENDLK
+    $pre .= <<'ENDCP';
+                              .;
+ENDCP
     $pre .= <<'ENDPRE';
         shift;
         mkdir -p src; >src/lib.rs;