Fortran support may be broken

[principis]

On Fedora 39 the CPPFortranMixed.test_hierarchies test fails:

FAILED testing/tests/cpp_fortran_mixed.py::CPPFortranMixed::test_hierarchies - RuntimeError: Matching child for [function] 'conversions::degrees_to_radians_s' with signature 'real(c_float) function conversions::degrees_to_radians_s(degrees_s)' not found!

Complete test results: test_output.txt

Version info:
Doxygen version: 1.9.7
Breathe version: 4.35.0
Sphinx version: 6.2.1
Python version: 3.12.1

[svenevs]

Thanks for reporting @principis!

It seems like either the gfortran version or doxygen@1.9.7 are at play here. The underlying problem is the testing framework is dumb / very picky, and wanted to find real(c_float) function conversions::degrees_to_radians_s(real(c_float), intent(in)) (note: the difference is the parameters degrees_s)

I will need to fiddle with things, if this is for a packaging build it might be appropriate to disable the test. I will see what I can dig up, I've had this change behavior in the past too and IIRC it was because doxygen changed how the xml worked.

[principis]

Thanks for your swift response! I'm packaging exhale for Fedora, I'll disable the test for now. 🙂

[svenevs]

I'll disable the test for now.

TL;DR: I'd say that's probably the right call, not much has changed code-wise for a couple of years, the latest release was really just to fix packaging mistakes that were starting to prevent people from installing the project on RTD using PyPI.

---

Hmmmmm... so after some digging around, it seems like at some point the fortran support broke. Possibly for quite some time. The next thing to check for me / anybody interested would be looking at different combinations of sphinx and breathe versions to see if there is a known point where the function signatures exhale was generating actually worked.

# See tox.ini hack, the variable needs the leadding '=='
# change X.Y.Z / A.B.C to try
SPHINX_VERSION='==X.Y.Z' BREATHE_VERSION='==A.B.C' tox -e py -- -k cpp_fortran_mixed --pdb -s

In this edge case, tests don't actually necessarily fail, it will just render the warning. To keep all of the builds around (warning: -k cpp_fortran_mixed is useful here, actually builds and renders the html for all projects if you run just tox -e py...):

diff --git a/testing/base.py b/testing/base.py
index 3360c81..96a8219 100644
--- a/testing/base.py
+++ b/testing/base.py
@@ -122,7 +122,7 @@ class ExhaleTestCaseMetaclass(type):
                 yield  # the test runs
                 # @no_cleanup sets self.testroot to [self.testroot] as a flag that
                 # cleanup should not transpire
-                if isinstance(self.testroot, six.string_types):
+                if False and isinstance(self.testroot, six.string_types):
                     # This cleanup happens between each test case, do not delete docs/
                     # until all tests for this class are done!
                     containmentFolder = self.getAbsContainmentFolder()
@@ -207,7 +207,7 @@ class ExhaleTestCaseMetaclass(type):
                 # perform cleanup by deleting the docs dir
                 # @no_cleanup sets self.testroot to [self.testroot] as a flag that
                 # cleanup should not transpire
-                if isinstance(self.testroot, six.string_types) and os.path.isdir(self.testroot):
+                if False and isinstance(self.testroot, six.string_types) and os.path.isdir(self.testroot):
                     shutil.rmtree(self.testroot)
 
                 self.testroot = None
@@ -225,6 +225,9 @@ class ExhaleTestCaseMetaclass(type):
                     self.checkAllFilesGenerated()
                     self.checkAllFilesIncluded()
 
+                    print("{{{{{ imma building }}}}}")
+                    self.app.build()
+
             attrs["test_common"] = test_common
 
             # Import the default hierarchy dictionaries from the testing/projects folder

And the place where you can fiddle with the parsing of things is here

diff --git a/exhale/graph.py b/exhale/graph.py
index c0d8e86..99d57ad 100644
--- a/exhale/graph.py
+++ b/exhale/graph.py
@@ -2196,7 +2196,16 @@ class ExhaleRoot(object):
                 # 2. The function parameter list.
                 parameters = []
                 for param in memberdef.find_all("param", recursive=False):
-                    parameters.append(param.type.text)
+                    # if param.type.text is not None and 'real(c_float), intent(in)' == param.type.text:
+                    if func_refid == "namespaceconversions_1af3f7e870092b4986419a4c8c56aaff63":
+                        # import pdb
+                        # pdb.set_trace()
+                        # (pdb) p param <<< that'll show you the function parameters
+                        #         these are the beautiful soup (xml) nodes getting parsed
+                        #         as we're building the {hacky} exhale representation
+                        parameters.append(param.defname.text)
+                    else:
+                        parameters.append(param.type.text)
                 func.parameters = utils.sanitize_all(parameters)
                 # 3. The template parameter list.
                 templateparamlist = memberdef.templateparamlist

Noting that modifying this method directly is also an easy way to hack

exhale/exhale/graph.py

Line 279 in c995925

def breathe_identifier(self):

There's other known problems even with C++ functions (overloads specifically, some work, some don't) 😶 While I'd love to be able to fix these things, they're usually in a corner case of "no known solution without making significant changes here and in breathe"...

---

When running tests against later versions of sphinx and breathe all kinds of other things broke, so it's not clear if this will get solved anytime soon 😞