fixup! Add options for the Julia binary and project path

Author: JamesWrigley

docs/src/juliacall.md

@@ -104,11 +104,11 @@ See [JuliaPkg](https://github.com/JuliaPy/PyJuliaPkg) for more details.
 ### Using existing environments
 
 It's possible to override the defaults and disable JuliaPkg entirely by setting
-the `PYTHON_JULIACALL_EXEPATH` and `PYTHON_JULIACALL_PROJECT` options. This is
-particularly useful when using shared environments on HPC systems that may be
-readonly. If `PYTHON_JULIACALL_PROJECT` is specified the project *must* already
-have PythonCall.jl already installed. If only one of these options is specified
-then JuliaPkg will still be loaded to get a default value for the other one.
+the `PYTHON_JULIACALL_EXE` and `PYTHON_JULIACALL_PROJECT` options (both must be
+set together). This is particularly useful when using shared environments on HPC
+systems that may be readonly. Note that the project set in
+`PYTHON_JULIACALL_PROJECT` *must* already have PythonCall.jl installed and it
+*must* match the JuliaCall version, otherwise loading Julia will fail.
 
 ## [Configuration](@id julia-config)
 

pysrc/juliacall/__init__.py

@@ -110,7 +110,7 @@ def int_option(name, *, accept_auto=False, **kw):
             raise ValueError(f'{s}: expecting an int'+(' or auto' if accept_auto else ""))
 
     def args_from_config(config):
-        argv = [config['exepath']]
+        argv = [config['exe']]
         for opt, val in config.items():
             if opt.startswith('opt_'):
                 if val is None:
@@ -147,32 +147,32 @@ def args_from_config(config):
     CONFIG['opt_handle_signals'] = choice('handle_signals', ['yes', 'no'])[0]
     CONFIG['opt_startup_file'] = choice('startup_file', ['yes', 'no'])[0]
     CONFIG['opt_heap_size_hint'] = option('heap_size_hint')[0]
-    CONFIG['opt_project'] = path_option('project', check_exists=True)[0]
-    CONFIG['exepath'] = path_option('exepath', check_exists=True)[0]
+    CONFIG['project'] = path_option('project', check_exists=True)[0]
+    CONFIG['exe'] = path_option('exe', check_exists=True)[0]
 
     # Stop if we already initialised
     if CONFIG['inited']:
         return
 
-    no_exepath = CONFIG['exepath'] is None
-    no_project = CONFIG['opt_project'] is None
-    if no_exepath or no_project:
+    have_exe = CONFIG['exe'] is not None
+    have_project = CONFIG['project'] is not None
+    if not have_exe and not have_project:
         # we don't import this at the top level because it is not required when
         # juliacall is loaded by PythonCall and won't be available, or if both
-        # `exepath` and `project` are set by the user.
+        # `exe` and `project` are set by the user.
         import juliapkg
 
         # Find the Julia executable and project
-        if no_exepath:
-            CONFIG['exepath'] = juliapkg.executable()
-        if no_project:
-            CONFIG['opt_project'] = juliapkg.project()
+        CONFIG['exe'] = juliapkg.executable()
+        CONFIG['project'] = juliapkg.project()
+    elif (not have_exe and have_project) or (have_exe and not have_project):
+        raise Exception("Both PYTHON_JULIACALL_PROJECT and PYTHON_JULIACALL_EXE must be set together, not only one of them.")
 
-    exepath = CONFIG['exepath']
-    project = CONFIG['opt_project']
+    exe = CONFIG['exe']
+    project = CONFIG['project']
 
     # Find the Julia library
-    cmd = [exepath, '--project='+project, '--startup-file=no', '-O0', '--compile=min',
+    cmd = [exe, '--project='+project, '--startup-file=no', '-O0', '--compile=min',
            '-e', 'import Libdl; print(abspath(Libdl.dlpath("libjulia")), "\\0", Sys.BINDIR)']
     libpath, default_bindir = subprocess.run(cmd, check=True, capture_output=True, encoding='utf8').stdout.split('\0')
     assert os.path.exists(libpath)