refactor: remove jinja2 dependency, use simple template engine

- Replace jinja2 with custom render_template() helper
- Support {{ var }} substitution and {% if %}...{% endif %} conditionals
- Remove jinja2 from pyproject.toml and requirements.txt
- Simplifies dependency tree and reduces install size

devgen/modules/commit_generator.py

@@ -33,8 +33,8 @@ from devgen.utils import (
     extract_commit_messages,
     get_commit_dry_run_path,
     is_file_recent,
-    load_template_env,
+    load_template,
-    render_custom_template,
+    render_template,
     sanitize_ai_commit_message,
 )
 
@@ -74,13 +74,13 @@ class CommitMessageBuilder:
 
     def __init__(
         self,
-        template_env,
+        template_str: str,
         config: Dict[str, Any],
         provider: str,
         model: str,
         debug: bool = False,
     ) -> None:
-        self.template_env = template_env
+        self.template_str = template_str
         self.config = config
         self.provider = provider
         self.model = model
@@ -97,25 +97,14 @@ class CommitMessageBuilder:
         use_emoji = self.config.get("emoji", True)
         ollama_host = self.config.get("ollama_host")
 
-        if custom_template:
+        template = custom_template or self.template_str
-            prompt = render_custom_template(
+        prompt = render_template(
-                custom_template,
+            template,
-                group_name=group,
+            group_name=group,
-                diff_text=diff,
+            diff_text=diff,
-                use_emoji=use_emoji,
+            use_emoji=use_emoji,
-                context=manifest_context,
+            context=manifest_context,
-            )
+        ).strip()
-        else:
-            prompt = (
-                self.template_env.get_template("commit_message.tpl")
-                .render(
-                    group_name=group,
-                    diff_text=diff,
-                    use_emoji=use_emoji,
-                    context=manifest_context,
-                )
-                .strip()
-            )
 
         provider = (
             extra_kwargs.get("provider") or self.config.get("provider") or self.provider
@@ -198,10 +187,10 @@ class CommitEngine:
             ),
             logger=self.logger,
         )
-        self.template_env = load_template_env("commit")
+        self.template_str = load_template("commit", "commit_message.tpl")
         self.cache = CacheManager(get_commit_dry_run_path())
         self.message_builder = CommitMessageBuilder(
-            self.template_env,
+            self.template_str,
             self.config,
             provider=self.provider,
             model=self.model,

devgen/utils.py

@@ -6,7 +6,6 @@ from pathlib import Path
 from typing import Any, Dict, Optional
 
 import yaml
-from jinja2 import Environment, FileSystemLoader
 
 
 def ensure_log_directory() -> Path:
@@ -216,21 +215,61 @@ def delete_file(filepath: Path | str) -> bool:
         return False
 
 
-def load_template_env(sub_dir: str) -> Environment:
+def load_template(sub_dir: str, name: str) -> str:
+    """Load a template file from the templates directory."""
     template_dir = Path(__file__).parent / "templates" / sub_dir
-    if not template_dir.is_dir():
+    template_path = template_dir / name
+    if not template_path.is_file():
         raise RuntimeError(
-            f"Template directory not found: {template_dir}. "
+            f"Template not found: {template_path}. "
             "The installation may be corrupted."
         )
-    return Environment(loader=FileSystemLoader(template_dir))
+    return template_path.read_text(encoding="utf-8")
 
 
-def render_custom_template(template_str: str, **context) -> str:
+def render_template(template_str: str, **context) -> str:
-    """Renders a Jinja2 template from a string."""
+    """Render a simple template with variable substitution and conditionals.
-    env = Environment()
+
-    template = env.from_string(template_str)
+    Supports:
-    return template.render(**context)
+    - {{ variable }} - variable substitution
+    - {% if condition %}...{% endif %} - conditional blocks
+    - {% if condition %}...{% else %}...{% endif %} - conditional with else
+    """
+    result = template_str
+
+    # Process conditional blocks: {% if var %}...{% endif %}
+    # and {% if var %}...{% else %}...{% endif %}
+    if_pattern = re.compile(
+        r"\{%\s*if\s+(\w+)\s*%\}(.*?)\{%\s*endif\s*%\}",
+        re.DOTALL,
+    )
+
+    def replace_if(match):
+        var_name = match.group(1)
+        content = match.group(2)
+        value = context.get(var_name)
+        if value:
+            # Check for else block
+            else_pattern = re.compile(r"\{%\s*else\s*%\}", re.DOTALL)
+            parts = else_pattern.split(content, 1)
+            return parts[0]
+        else:
+            else_pattern = re.compile(r"\{%\s*else\s*%\}", re.DOTALL)
+            parts = else_pattern.split(content, 1)
+            return parts[1] if len(parts) > 1 else ""
+
+    result = if_pattern.sub(replace_if, result)
+
+    # Process variable substitutions: {{ variable }}
+    var_pattern = re.compile(r"\{\{\s*(\w+)\s*\}\}")
+
+    def replace_var(match):
+        var_name = match.group(1)
+        return str(context.get(var_name, ""))
+
+    result = var_pattern.sub(replace_var, result)
+
+    return result
 
 
 def load_config() -> Dict[str, Any]:
@@ -338,7 +377,8 @@ __all__ = [
     "get_git_staged_files",
     "read_file_content",
     "delete_file",
-    "load_template_env",
+    "load_template",
+    "render_template",
     "load_config",
     "get_questionary_style",
     "is_token_limit_error",

pyproject.toml

@@ -27,7 +27,6 @@ classifiers = [
 dependencies = [
     "anthropic>=0.75.0",
     "google-genai>=0.1.0",
-    "jinja2>=3.1.6",
     "openai>=2.11.0",
     "pyyaml>=6.0.3",
     "questionary>=2.1.1",

requirements.txt

@@ -1,6 +1,5 @@
 anthropic==0.109.1
 google-genai==2.8.0
-jinja2==3.1.6
 openai==2.41.1
 pre-commit==4.6.0
 pyyaml==6.0.3