fix

src/pystream.cpp

@@ -11,9 +11,9 @@
 pystreambuf::pystreambuf(py::object iohandle, int size)
     : buffer_(size), iohandle_(iohandle) {
   // this ctor must not throw
-  if (hasattr(iohandle, "readinto") || hasattr(iohandle, "readinto1"))
-    readinto_ =
-        iohandle.attr(py::hasattr(iohandle, "readinto1") ? "readinto1" : "readinto");
+  const bool has_readinto1 = hasattr(iohandle, "readinto1");
+  if (has_readinto1 || hasattr(iohandle, "readinto"))
+    readinto_ = iohandle.attr(has_readinto1 ? "readinto1" : "readinto");
   if (hasattr(iohandle, "write")) write_ = iohandle.attr("write");
   char* b = buffer_.mutable_data();
   setp(b, b + size);
@@ -86,9 +86,9 @@ int pystreambuf::sync_() {
 }
 
 void pystreambuf::pywrite_buffer() {
-  const int s = std::distance(pbase(), pptr());
   py::gil_scoped_acquire g;
   assert(write_);
+  const int s = std::distance(pbase(), pptr());
   // TODO there is probably a more efficient way
   write_(buffer_[py::slice(0, s, 1)]);
 }

tests/test_io.py

@@ -20,8 +20,8 @@
 def test_pystream_1():
     fn = str(Path(__file__).parent / "sibyll21.dat")
     with open(fn, "rb") as f:
-        with pyiostream(f, 1000) as pis:
-            with io.ReaderAscii(pis) as r:
+        with pyiostream(f, 1000) as s:
+            with io.ReaderAscii(s) as r:
                 ev1 = r.read()
     with io.ReaderAscii(fn) as r:
         ev2 = r.read()
@@ -37,8 +37,8 @@ def test_pystream_2():
             f2.write(f.read())
 
     with gzip.open(fn2) as f:
-        with pyiostream(f, 1000) as pis:
-            with io.ReaderAscii(pis) as r:
+        with pyiostream(f, 1000) as s:
+            with io.ReaderAscii(s) as r:
                 ev1 = r.read()
 
     with io.ReaderAscii(fn) as r:
@@ -52,14 +52,14 @@ def test_pystream_2():
 def test_pystream_3(evt):  # noqa
     fn = "test_pystream_3.dat.gz"
     with gzip.open(fn, "w") as f:
-        with pyiostream(f, 1000) as pis:
-            with io.WriterAscii(pis) as w:
+        with pyiostream(f, 1000) as s:
+            with io.WriterAscii(s) as w:
                 w.write(evt)
 
     with gzip.open(fn) as f:
-        pis = pyiostream(f, 1000)
-        with io.ReaderAscii(pis) as r:
-            evt2 = r.read()
+        with pyiostream(f, 1000) as s:
+            with io.ReaderAscii(s) as r:
+                evt2 = r.read()
 
     assert evt == evt2