ADR 20251216 implement lazy loading in templatemanager Implement lazy loading in TemplateManager

Implement lazy loading in TemplateManager

Property	Value
ID	20251216-implement-lazy-loading-in-templatemanager
Status	accepted
Date	2025-12-16
Deciders	Claude, User
Tags	architecture, patterns, performance

Implement lazy loading in TemplateManager

Context and Problem Statement

The TemplateManager needs to discover and load issue templates from both bundled resources and project directories. Template discovery involves file I/O operations that can be slow, especially in projects with many templates. We need to balance performance with usability.

Decision Drivers

• Performance: Minimize startup overhead
• User experience: Fast command execution
• Resource efficiency: Don't load unused templates
• Code simplicity: Avoid complex caching mechanisms

Considered Options

• Option 1: Load all templates eagerly during initialization
• Option 2: Lazy loading with cache (CHOSEN)
• Option 3: No caching, load templates on every request

Decision Outcome

Chosen option: "Lazy loading with cache", because:

• Prevents unnecessary file I/O until templates are needed
• Caches results for subsequent access
• Simple implementation with _ensure_loaded() pattern
• Optimal balance of performance and simplicity

Consequences

• Good, because fast startup (no I/O until needed)
• Good, because subsequent access is cached
• Good, because simple implementation
• Neutral, requires explicit reload() for template updates

Implementation

# issue_template.py:500-519
class TemplateManager:
    def __init__(self, project_root: Path | None = None) -> None:
        self._project_root = project_root or Path.cwd()
        self._templates: dict[str, IssueTemplate] = {}
        self._loaded = False  # Lazy loading flag

    def _ensure_loaded(self) -> None:
        """Ensure templates are loaded (lazy loading)."""
        if not self._loaded:
            self._templates = self.discover_templates()
            self._loaded = True

    def get_template(self, type_or_name: str) -> IssueTemplate | None:
        self._ensure_loaded()  # Load on first access
        resolved_name = TYPE_ALIASES.get(type_or_name.lower(), type_or_name.lower())
        return self._templates.get(resolved_name)

Validation

Code review confirmed:

• Lazy loading implemented correctly
• All public methods call _ensure_loaded()
• reload() method available for cache invalidation

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Synced from git-adr on 2025-12-17 09:49 UTC