don't leak an FD in lz4 (de)compression

Seen first in #826783, but as this buglog also shows leaked uncompressed
files as well we don't close it just yet.

(cherry picked from commit 6f35be91c9e86e463bca7df6eadf05412c7b732c)

2 files changed, 49 insertions, 0 deletions

diff --git a/test/interactive-helper/makefile b/test/interactive-helper/makefile
index 4633b78ce..096767c41 100644
--- a/test/interactive-helper/makefile
+++ b/test/interactive-helper/makefile
@@ -33,6 +33,12 @@ LIB_MAKES = apt-pkg/makefile
 SOURCE = test_udevcdrom.cc
 include $(PROGRAM_H)
 
+PROGRAM=test_fileutl
+SLIBS = -lapt-pkg
+LIB_MAKES = apt-pkg/makefile
+SOURCE = test_fileutl.cc
+include $(PROGRAM_H)
+
 # Program for checking rpm versions
 #PROGRAM=rpmver
 #SLIBS = -lapt-pkg -lrpm
diff --git a/test/interactive-helper/test_fileutl.cc b/test/interactive-helper/test_fileutl.cc
new file mode 100644
index 000000000..e660c2981
--- /dev/null
+++ b/test/interactive-helper/test_fileutl.cc
@@ -0,0 +1,43 @@
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/error.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#include <iostream>
+#include <string>
+
+static void callsystem(std::string const &call)
+{
+   auto ret = system(call.c_str());
+   if (WIFEXITED(ret) == false || WEXITSTATUS(ret) != 0)
+      _error->Error("Calling %s failed!", call.c_str());
+}
+
+int main(int, char ** argv)
+{
+	auto const pid = getpid();
+	std::string ls;
+	strprintf(ls, "ls -l /proc/%d/fd", pid);
+	callsystem(ls);
+	FileFd t;
+	t.Open(argv[1], FileFd::ReadOnly, FileFd::Extension);
+	callsystem(ls);
+	char buf[1024];
+	unsigned long long act;
+	while (t.Read(buf, sizeof(buf), &act))
+		if (act == 0)
+			break;
+	callsystem(ls);
+	t.Seek(5);
+	callsystem(ls);
+	t.Close();
+	callsystem(ls);
+	auto const ret = _error->PendingError();
+	_error->DumpErrors();
+	return ret;
+}