Add --heap-size-hint parameter (#547)

* refactor: avoid spooky action at a distance in init

* feat: add heap-size-hint

* docs: add heap-size-hint to docs and release notes

---------

Co-authored-by: Christopher Doris <github.com/cjdoris>

Author: MilesCranmer

docs/src/juliacall.md

@@ -124,6 +124,7 @@ be configured in two ways:
 | `-X juliacall-threads=<N\|auto>` | `PYTHON_JULIACALL_THREADS=<N\|auto>` | Launch N threads. |
 | `-X juliacall-warn-overwrite=<yes\|no>` | `PYTHON_JULIACALL_WARN_OVERWRITE=<yes\|no>` | Enable or disable method overwrite warnings. |
 | `-X juliacall-autoload-ipython-extension=<yes\|no>` | `PYTHON_JULIACALL_AUTOLOAD_IPYTHON_EXTENSION=<yes\|no>` | Enable or disable IPython extension autoloading. |
+| `-X juliacall-heap-size-hint=<N>` | `PYTHON_JULIACALL_HEAP_SIZE_HINT=<N>` | Hint for initial heap size in bytes. |
 
 ## [Multi-threading](@id py-multi-threading)
 

docs/src/releasenotes.md

@@ -1,5 +1,8 @@
 # Release Notes
 
+## Unreleased
+* Added `PYTHON_JULIACALL_HEAP_SIZE_HINT` option to configure initial Julia heap size.
+
 ## 0.9.24 (2025-01-22)
 * Bug fixes.
 

pysrc/juliacall/__init__.py

@@ -109,9 +109,9 @@ def int_option(name, *, accept_auto=False, **kw):
         except ValueError:
             raise ValueError(f'{s}: expecting an int'+(' or auto' if accept_auto else ""))
 
-    def args_from_config():
-        argv = [CONFIG['exepath']]
-        for opt, val in CONFIG.items():
+    def args_from_config(config):
+        argv = [config['exepath']]
+        for opt, val in config.items():
             if opt.startswith('opt_'):
                 if val is None:
                     if opt == 'opt_handle_signals':
@@ -146,6 +146,7 @@ def args_from_config():
     CONFIG['opt_warn_overwrite'] = choice('warn_overwrite', ['yes', 'no'])[0]
     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]
 
     # Stop if we already initialised
     if CONFIG['inited']:
@@ -181,7 +182,7 @@ def args_from_config():
     CONFIG['lib'] = lib = c.PyDLL(libpath, mode=c.RTLD_GLOBAL)
 
     # parse options
-    argc, argv = args_from_config()
+    argc, argv = args_from_config(CONFIG)
     jl_parse_opts = lib.jl_parse_opts
     jl_parse_opts.argtypes = [c.c_void_p, c.c_void_p]
     jl_parse_opts.restype = None