Only set linetrace=True when compiling for coverage

Author: MatthiasValvekens

.github/workflows/coverage.yml

@@ -16,7 +16,12 @@ jobs:
     steps:
       - name: Acquire sources
         uses: actions/checkout@v4
-
+      - name: Arm coverage-only compiler directives
+        # Unfortunately, it doesn't seem to be possible to pass directives
+        # to Cython through environment variables: https://github.com/cython/cython/issues/3930
+        # Doing it here is still better than introducing a non-declarative setup.py into the
+        # build again.
+        run: sed -i 's/#coverage#cython/#cython/g' pkcs11/*.pyx
       - name: Setup Python
         uses: actions/setup-python@v5
         with:

pkcs11/_pkcs11.pxd

@@ -625,10 +625,11 @@ cdef inline CK_ULONG_buffer(length):
     return array(shape=(length,), itemsize=sizeof(CK_ULONG), format='L')
 
 
-cdef inline object map_rv_to_error(
-        CK_RV rv
-):
+# Note: this `cdef inline` declaration doesn't seem to be consistently labelled
+# as executed by Cython's line tracing, so we flag it as nocover
+# to avoid noise in the metrics.
 
+cdef inline object map_rv_to_error(CK_RV rv):  # pragma: nocover
     if rv == CKR_ATTRIBUTE_TYPE_INVALID:
         exc = AttributeTypeInvalid()
     elif rv == CKR_ATTRIBUTE_VALUE_INVALID:

pkcs11/_pkcs11.pyx

@@ -1,6 +1,5 @@
-#!python
 #cython: language_level=3
-#cython: linetrace=True
+#coverage#cython: linetrace=True
 """
 High-level Python PKCS#11 Wrapper.