Add C compiler dep when .xs files are found. (#4599)

* Added `.xs` to the list of extensions that trigger the addition of a C
compiler app for Perl recipes created by conda skeleton.
* test: Add CPAN skeleton test for XS

---------

Co-authored-by: Felix Kuehnl <[email protected]>
Co-authored-by: Marcel Bargull <[email protected]>

conda_build/skeletons/cpan.py

@@ -205,7 +205,7 @@ def get_build_dependencies_from_src_archive(package_url, sha256, src_cache):
         need_f = any([f.name.lower().endswith(('.f', '.f90', '.f77', '.f95', '.f03')) for f in tf])
         # Fortran builds use CC to perform the link (they do not call the linker directly).
         need_c = True if need_f else \
-            any([f.name.lower().endswith('.c') for f in tf])
+            any([f.name.lower().endswith(('.c', '.xs')) for f in tf])
         need_cxx = any([f.name.lower().endswith(('.cxx', '.cpp', '.cc', '.c++'))
                         for f in tf])
         need_autotools = any([f.name.lower().endswith('/configure') for f in tf])

news/4599-add-cpan-xs-detection

@@ -0,0 +1,19 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* conda skeleton cpan now correctly adds a C compiler as dependency if the distribution contains an `.xs` file
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

tests/test_api_skeleton_cpan.py

@@ -0,0 +1,23 @@
+# Copyright (C) 2014 Anaconda, Inc
+# SPDX-License-Identifier: BSD-3-Clause
+'''
+Integrative tests of the CPAN skeleton that start from
+conda_build.api.skeletonize and check the output files
+'''
+
+
+import pytest
+
+from conda_build import api
+from conda_build.jinja_context import compiler
+
+
+@pytest.mark.slow
+@pytest.mark.flaky(rerun=5, reruns_delay=2)
+def test_xs_needs_c_compiler(testing_config):
+    """Perl packages with XS files need a C compiler"""
+    # This uses Sub::Identify=0.14 since it includes no .c files but a .xs file.
+    api.skeletonize("Sub::Identify", version="0.14", repo="cpan", config=testing_config)
+    m = api.render("perl-sub-identify/0.14", finalize=False, bypass_env_check=True)[0][0]
+    build_requirements = m.get_value("requirements/build")
+    assert compiler("c", testing_config) in build_requirements