Fix get_min_versions.py to respect Python version markers

The script now evaluates python_version markers in dependencies and only
extracts minimum versions for packages applicable to the current Python
version. This ensures:

- Python 3.9 CI jobs use LangChain 0.3.x minimums
- Python 3.10+ CI jobs use LangChain 1.x minimums

This prevents incompatible package combinations like langchain-core 0.3.78
with langchain-openai 1.1.0 (which requires langchain-core >= 1.1.0).

Author: fede-kamel

.github/scripts/get_min_versions.py

@@ -47,25 +47,43 @@ def get_min_version_from_toml(toml_path: str):
     # Parse dependencies list into a dictionary
     # Format: "package-name>=x.x.x,<y.y.y" or "package-name>=x.x.x; python_version < '3.10'"
     dependencies = {}
+    python_version = f"{sys.version_info.major}.{sys.version_info.minor}"
+
     for dep in dependencies_list:
-        # Remove environment markers (everything after semicolon)
-        dep_without_marker = dep.split(";")[0].strip()
+        # Check if there's a Python version marker
+        if ";" in dep:
+            dep_without_marker, marker = dep.split(";", 1)
+            dep_without_marker = dep_without_marker.strip()
+            marker = marker.strip()
+
+            # Check if this dependency applies to current Python version
+            # Handle python_version < '3.10' and python_version >= '3.10' markers
+            applies_to_current = True
+            if "python_version" in marker:
+                if "<" in marker and not ">=" in marker:
+                    # python_version < 'X.Y'
+                    match = re.search(r"python_version\s*<\s*['\"](\d+\.\d+)['\"]", marker)
+                    if match:
+                        max_version = match.group(1)
+                        applies_to_current = parse_version(python_version) < parse_version(max_version)
+                elif ">=" in marker:
+                    # python_version >= 'X.Y'
+                    match = re.search(r"python_version\s*>=\s*['\"](\d+\.\d+)['\"]", marker)
+                    if match:
+                        min_version_marker = match.group(1)
+                        applies_to_current = parse_version(python_version) >= parse_version(min_version_marker)
+
+            if not applies_to_current:
+                continue
+        else:
+            dep_without_marker = dep.strip()
 
         # Extract package name and version spec
         match = re.match(r"^([a-zA-Z0-9_-]+)(.*)$", dep_without_marker)
         if match:
             pkg_name = match.group(1)
             version_spec = match.group(2)
-
-            # If this package already exists, collect both version specs
-            if pkg_name in dependencies:
-                # Store as a list to handle multiple version constraints
-                if isinstance(dependencies[pkg_name], list):
-                    dependencies[pkg_name].append(version_spec)
-                else:
-                    dependencies[pkg_name] = [dependencies[pkg_name], version_spec]
-            else:
-                dependencies[pkg_name] = version_spec
+            dependencies[pkg_name] = version_spec
 
     # Initialize a dictionary to store the minimum versions
     min_versions = {}
@@ -74,23 +92,8 @@ def get_min_version_from_toml(toml_path: str):
     for lib in MIN_VERSION_LIBS:
         # Check if the lib is present in the dependencies
         if lib in dependencies:
-            # Get the version string(s)
             version_spec = dependencies[lib]
-
-            # Handle list format (multiple version constraints for different Python versions)
-            if isinstance(version_spec, list):
-                # Extract all version strings from the list and find the minimum
-                versions = []
-                for spec in version_spec:
-                    if spec:
-                        versions.append(get_min_version(spec))
-
-                # If we found versions, use the minimum one
-                if versions:
-                    min_version = min(versions, key=parse_version)
-                    min_versions[lib] = min_version
-            elif isinstance(version_spec, str) and version_spec:
-                # Handle simple string format
+            if version_spec:
                 min_version = get_min_version(version_spec)
                 min_versions[lib] = min_version