Issue #8681: Make the zlib module's error messages more informative when
the zlib itself doesn't give any detailed explanation.
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index bb52fdc..183f01e 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -72,10 +72,24 @@
static void
zlib_error(z_stream zst, int err, char *msg)
{
- if (zst.msg == Z_NULL)
+ const char *zmsg = zst.msg;
+ if (zmsg == Z_NULL) {
+ switch (err) {
+ case Z_BUF_ERROR:
+ zmsg = "incomplete or truncated stream";
+ break;
+ case Z_STREAM_ERROR:
+ zmsg = "inconsistent stream state";
+ break;
+ case Z_DATA_ERROR:
+ zmsg = "invalid input data";
+ break;
+ }
+ }
+ if (zmsg == Z_NULL)
PyErr_Format(ZlibError, "Error %d %s", err, msg);
else
- PyErr_Format(ZlibError, "Error %d %s: %.200s", err, msg, zst.msg);
+ PyErr_Format(ZlibError, "Error %d %s: %.200s", err, msg, zmsg);
}
PyDoc_STRVAR(compressobj__doc__,
@@ -248,8 +262,7 @@
* process the inflate call() due to an error in the data.
*/
if (zst.avail_out > 0) {
- PyErr_Format(ZlibError, "Error %i while decompressing data",
- err);
+ zlib_error(zst, err, "while decompressing data");
inflateEnd(&zst);
goto error;
}