Allow to have some default ipywidgets version

Author: IvanHCenalmor

.tools/python/merge_requirements.py

@@ -4,13 +4,17 @@
 This updated script resolves simple version conflicts by choosing the newest version seen
 for a given package (and emits a pinned `pkg==<newest>`). It still preserves
 non-package lines (pip options, VCS/URLs) and supports simple `-r` includes.
+
+It also automatically adds ipywidgets if missing, with a version determined by
+Python, JupyterLab, and matplotlib versions from environment.yaml.
 """
 from pathlib import Path
 import argparse
 import sys
 from collections import OrderedDict
 from datetime import datetime
 import re
+import yaml
 
 
 def normalize_line(line: str) -> str:
@@ -129,6 +133,50 @@ def find_requirements_files(source_dir: Path):
     return sorted(source_dir.rglob("requirements*.txt"))
 
 
+def read_environment_yaml(env_path: Path) -> dict:
+    """Read environment.yaml and extract Python, JupyterLab, matplotlib versions."""
+    if not env_path.exists():
+        return {}
+    try:
+        data = yaml.safe_load(env_path.read_text(encoding="utf-8"))
+        versions = {}
+        for dep in data.get("dependencies", []):
+            if isinstance(dep, str):
+                if dep.startswith("python="):
+                    versions["python"] = dep.split("=")[-1]
+                elif dep.startswith("jupyterlab="):
+                    versions["jupyterlab"] = dep.split("=")[-1]
+                elif dep.startswith("matplotlib="):
+                    versions["matplotlib"] = dep.split("=")[-1]
+        return versions
+    except Exception:
+        return {}
+
+
+def resolve_ipywidgets_version(env_versions: dict) -> str:
+    """Resolve ipywidgets version based on Python, JupyterLab, matplotlib versions.
+    
+    Returns a version spec string like ">=7.0.0,<8.0.0" or a pinned version.
+    """
+    py_ver = env_versions.get("python", "3.11")
+    jl_ver = env_versions.get("jupyterlab", "4.0")
+    mpl_ver = env_versions.get("matplotlib", "3.0")
+    
+    # Simple heuristic: ipywidgets 8.x for modern stacks, 7.x for older
+    try:
+        py_major, py_minor = map(int, py_ver.split(".")[:2])
+        jl_major = int(jl_ver.split(".")[0])
+        
+        if jl_major >= 4 and py_major >= 3 and py_minor >= 9:
+            return "8.1.1"  # Latest stable for modern Python + JupyterLab 4
+        elif py_major >= 3 and py_minor >= 8:
+            return "8.0.4"  # Good for Python 3.8+
+        else:
+            return "7.7.2"  # Fallback for older environments
+    except Exception:
+        return ">=7.0.0"  # Safe fallback
+
+
 def main():
     parser = argparse.ArgumentParser(description="Merge multiple requirements.txt files into one.")
     parser.add_argument("--source-dir", default="notebooks", help="Directory to scan for requirements files")
@@ -163,6 +211,25 @@ def main():
     for ol in other_lines.keys():
         final_lines.append(ol)
 
+    # Check if ipywidgets is already present
+    has_ipywidgets = "ipywidgets" in pkgs
+    
+    # If not, resolve and add it based on environment.yaml
+    if not has_ipywidgets:
+        env_path = Path(args.env_output) if args.generate_env else Path("environment.yaml")
+        env_versions = read_environment_yaml(env_path)
+        ipyw_version = resolve_ipywidgets_version(env_versions)
+        
+        # Add to pkgs and pkg_order
+        pkgs["ipywidgets"] = {
+            "name": "ipywidgets",
+            "pinned": True,
+            "ver": ipyw_version,
+            "marker": ""
+        }
+        pkg_order.append("ipywidgets")
+        print(f"Added ipywidgets=={ipyw_version} (resolved from environment)")
+
     # collect package lines
     if args.sort:
         pkg_keys = sorted(pkg_order, key=str.casefold)