fix(tracer): error when encoding bytes and adding a string [backport 3.9] (#13718)

Backport 2e13f18 from #13419 to 3.9.

fixes error when we try to concat the string 'truncated' to bytes

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Co-authored-by: Rachel Yang <[email protected]>
Co-authored-by: Quinna Halim <[email protected]>
Co-authored-by: Brett Langdon <[email protected]>

Author: 4 people

ddtrace/internal/_encoding.pyx

@@ -98,7 +98,10 @@ cdef inline int array_prefix_size(stdint.uint32_t l):
 
 cdef inline object truncate_string(object string):
     if string and len(string) > MAX_SPAN_META_VALUE_LEN:
-        return string[:TRUNCATED_SPAN_ATTRIBUTE_LEN - 14] + "<truncated>..."
+        if PyBytesLike_Check(string):
+            return string[:TRUNCATED_SPAN_ATTRIBUTE_LEN - 14] + b"<truncated>..."
+        elif PyUnicode_Check(string):
+            return string[:TRUNCATED_SPAN_ATTRIBUTE_LEN - 14] + "<truncated>..."
     return string
 
 cdef inline int pack_bytes(msgpack_packer *pk, char *bs, Py_ssize_t l):

releasenotes/notes/encode-bytes-974d93cec3725455.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    tracing: This resolves a ``TypeError`` in encoding when truncating a large bytes object.

tests/integration/test_integration_snapshots.py

@@ -291,6 +291,21 @@ def test_encode_span_with_large_string_attributes(encoding):
             span.set_tag(key="c" * 25001, value="d" * 2000)
 
 
+@pytest.mark.parametrize("encoding", ["v0.4", "v0.5"])
+@pytest.mark.snapshot()
+def test_encode_span_with_large_bytes_attributes(encoding):
+    from ddtrace import tracer
+
+    with override_global_config(dict(_trace_api=encoding)):
+        name = b"a" * 25000
+        resource = b"b" * 25001
+        key = b"c" * 25001
+        value = b"d" * 2000
+
+        with tracer.trace(name=name, resource=resource) as span:
+            span.set_tag(key=key, value=value)
+
+
 @pytest.mark.parametrize("encoding", ["v0.4", "v0.5"])
 @pytest.mark.snapshot()
 def test_encode_span_with_large_unicode_string_attributes(encoding):