gh-142787: Fix assertion failure in sqlite3 blob slice

Abdoulrasheed · Abdoulrasheed · commit 97ca005b1d1e · 2025-12-16T13:21:59.000Z
diff --git a/Misc/NEWS.d/next/Library/2024-12-16-142787.gh-issue-142787.blob_slice.rst b/Misc/NEWS.d/next/Library/2024-12-16-142787.gh-issue-142787.blob_slice.rst
@@ -0,0 +1,2 @@
+Fix assertion failure in :mod:`sqlite3` blob subscript when slicing with
+indices that result in an empty slice.
diff --git a/Modules/_sqlite/blob.c b/Modules/_sqlite/blob.c
@@ -439,6 +439,10 @@ subscript_slice(pysqlite_Blob *self, PyObject *item)
         return NULL;
     }
 
+    if (len == 0) {
+        return PyBytes_FromStringAndSize(NULL, 0);
+    }
+
     if (step == 1) {
         return read_multiple(self, len, start);
     }

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Fix assertion failure in :mod:`sqlite3` blob subscript when slicing with
	`2`	`+indices that result in an empty slice.`
Original file line number	Diff line number	Diff line change
`@@ -439,6 +439,10 @@ subscript_slice(pysqlite_Blob self, PyObject item)`
`439`	`439`	`return NULL;`
`440`	`440`	`}`
`441`	`441`
	`442`	`+ if (len == 0) {`
	`443`	`+ return PyBytes_FromStringAndSize(NULL, 0);`
	`444`	`+ }`
	`445`	`+`
`442`	`446`	`if (step == 1) {`
`443`	`447`	`return read_multiple(self, len, start);`
`444`	`448`	`}`