pr-desc-cli/dist/pr-generator.js

AI-powered PR description generator

import { generateText } from "ai";
import { getAIModel } from "./models.js";
export async function generatePRDescription(changes, options) {
    const model = await getAIModel(options.provider, options.model);
    const maxFiles = options.maxFiles ?? 20;
    const maxDiffLines = options.maxDiffLines ?? 500;
    const fileSummaries = changes.files
        .slice(0, maxFiles)
        .map((f) => {
        const patch = f.patch
            ? f.patch.slice(0, maxDiffLines) +
                (f.patch.length > maxDiffLines ? "..." : "")
            : "";
        return `FILE: ${f.path} STATUS: ${f.status} +${f.additions} -${f.deletions}\n${patch}`;
    })
        .join("\n\n");
    function buildPrompt(changes, template, fileSummaries, customTemplateContent) {
        const gitDataSection = `
## Git Context
**Base Branch:** ${changes.baseBranch}  
**Current Branch:** ${changes.currentBranch}  
**Files Changed:** ${changes.files.length}  
**Insertions:** ${changes.stats.insertions}  
**Deletions:** ${changes.stats.deletions}  

### Recent Commits
${changes.commits
            .map((commit) => `- ${commit.message.trim()} (${commit.hash.slice(0, 7)})`)
            .join("\n")}

### File Changes summary
${fileSummaries}
`;
        const finalAiInstruction = `
Do *not* include any meta information or explanations — just the PR content
Do **not** include labels like "PR Description:", "Title:", or meta text — only the final PR content.
Do *not* include any labels like "Here's a suggested PR description", "Feel free to modify it"
`;
        // Check for custom template content
        if (customTemplateContent) {
            return `
You are an expert software engineer writing a Pull Request description.
Analyze the following git changes and generate a PR description that strictly adheres to the provided custom Markdown template.
Fill in the sections of the template using the git changes data.

${gitDataSection}

## Custom PR Template:
${customTemplateContent}

Please generate the PR description by filling the custom template based on the git changes provided.
${finalAiInstruction}
`;
        }
        const templates = {
            standard: `${gitDataSection}

You are an expert software engineer.  
Write a **standard** **production-ready** Pull Request description in clean Markdown.
${finalAiInstruction}  

Follow this exact structure:

# Title
[Short, clear title summarizing the change in under 10 words.]

## Summary of Changes
[Concise high-level overview of what this PR does, focusing on the end result.]

## What Was Changed
[List the specific code modifications, features added, bugs fixed, or files updated. Use bullet points for clarity.]

## Why This Change Was Made
[Explain the rationale, problem solved, or context from related work.]


## Technical Details
[Include implementation specifics, relevant algorithms, dependencies, DB changes, env vars, or API modifications.]


## How to Test
1. Checkout this branch.
2. Run \`npm install\` and \`npm run dev\`.
3. Navigate to **[feature/page/URL]**.
4. Perform **[specific actions]**.
5. Verify **[expected results]**.


## Breaking Changes
[List any breaking changes or write \`None\`. Include migration steps if applicable.]
**NOTE** Breaking Changes **includes but not limited** to the following conditions:

1. A new feature implemented
2. A Big refactor to current implementation

## Related Issues / References
[Optional: Link to Jira ticket, GitHub issue, or related PR.]
`,
            detailed: `${gitDataSection}

You are an expert software engineer.  
Write a **production-ready** and **comprehensive** Pull Request description in clean Markdown.  
${finalAiInstruction}

Follow this exact structure:

# Title
[Short, clear title summarizing the change in under 10 words.]

## Summary of Changes
[Brief high-level overview of what this PR achieves.]

## Changes Made
[Detailed bullet list of modifications, new features, and fixes.]

## Technical Details
[Explain the approach, important design decisions, dependencies, DB changes, env vars, or API changes.]

## Testing
[Steps to test the PR — actions, expected results, and verification points.]

## Breaking Changes
[List any breaking changes or write \`None\`. Include migration instructions if necessary.]

## Additional Notes
[Optional extra context, performance considerations, or known limitations.]
`,
            minimal: `${gitDataSection}

You are an expert software engineer.  
Write a **concise** and **minimal** Pull Request description in clean Markdown.  
${finalAiInstruction}

Follow this exact structure:

# Title
[Short, clear title summarizing the change.]

## Summary
[A two line summary of what was changed.]

## Key Changes
[Bullet points summarizing the main changes.]
`,
        };
        return templates[template] || templates.standard;
    }
    const prompt = buildPrompt(changes, options.template, fileSummaries, options.customTemplateContent);
    if (options.refineFrom) {
        const prev = options.refineFrom.trim();
        const refinePrompt = `Previous PR description:
"
${prev}
"

Based on the git diff below, improve or correct the suggestion to make it more clear, complete, and professional. Return ONLY the corrected PR content (no explanation):
<diff>
${fileSummaries}
</diff>

Rules:
- Do not include any meta information or explanations — just the PR content
- Do not include labels like "PR Description:", "Title:", or meta text — only the final PR content.
- Do not include any labels like "Here's a suggested PR description", "Feel free to modify it"
${options.template ? `- Follow the ${options.template} template structure` : ""}
${options.customTemplateContent
            ? `- Follow the provided custom template structure`
            : ""}
`;
        try {
            const res = await generateText({
                model,
                prompt: refinePrompt,
                temperature: 0.15,
                maxTokens: 800,
            });
            const out = (res?.text ??
                res?.output?.[0]?.content ??
                "").trim();
            return out || prev;
        }
        catch (err) {
            // just fallback to original prompt
            console.error("Error during refine:", err);
            return prev;
        }
    }
    try {
        const res = await generateText({
            model,
            prompt,
            temperature: 0.3,
            maxTokens: 800,
        });
        return (res?.text ??
            res?.output?.[0]?.content ??
            "Error: No response from AI").trim();
    }
    catch (err) {
        console.error("Error during PR generation:", err);
        return "Error: Unable to generate PR description";
    }
}