Merge pull request #13 from Codium-ai/docs/pr_compression_doc

Docs/pr compression doc

PR_COMPRESSION.md

@@ -0,0 +1,42 @@
+# Git Patch Logic
+There are two scenarios:
+1. The PR is small enough to fit in a single prompt (including system and user prompt)
+2. The PR is too large to fit in a single prompt (including system and user prompt)
+
+For both scenarios, we first use the following strategy
+#### Repo language prioritization strategy
+
+We prioritize the languages of the repo based on the following criteria:
+1. Exclude binary files and non code files (e.g. images, pdfs, etc)
+2. Given the main languages used in the repo
+2. We sort the PR files by the most common languages in the repo (in descending order): 
+   * ```[[file.py, file2.py],[file3.js, file4.jsx],[readme.md]]```
+   
+
+## Small PR
+In this case, we can fit the entire PR in a single prompt:
+1. Exclude binary files and non code files (e.g. images, pdfs, etc)
+2. We Expand the surrounding context of each patch to 6 lines above and below the patch
+## Large PR
+
+### Motivation
+Pull Requests can be very long and contain a lot of information with varying degree of relevance to the pr-agent.
+We want to be able to pack as much information as possible in a single LMM prompt, while keeping the information relevant to the pr-agent.
+
+
+
+#### PR compression strategy
+We prioritize additions over deletions:
+ - Combine all deleted files into a single list (`deleted files`)
+ - File patches are a list of hunks, remove all hunks of type deletion-only from the hunks in the file patch
+####  Adaptive and token-aware file patch fitting
+We use [tiktoken](https://github.com/openai/tiktoken) to tokenize the patches after the modifications described above, and we use the following strategy to fit the patches into the prompt:
+1. Withing each language we sort the files by the number of tokens in the file (in descending order):
+   * ```[[file2.py, file.py],[file4.jsx, file3.js],[readme.md]]```
+2. Iterate through the patches in the order described above
+2. Add the patches to the prompt until the prompt reaches a certain buffer from the max token length
+3. If there are still patches left, add the remaining patches as a list called `other modified files` to the prompt until the prompt reaches the max token length (hard stop), skip the rest of the patches.
+4. If we haven't reached the max token length, add the `deleted files` to the prompt until the prompt reaches the max token length (hard stop), skip the rest of the patches.
+
+### Example
+![](./pics/git_patch_logic.png)

README.md

@@ -14,6 +14,7 @@ CodiumAI `pr-agent` is an open-source tool is powered by GPT-4 aming to help dev
 - [Quickstart](#Quickstart)
 - [Usage and Tools](#usage-and-tools)
 - [Configuration](#Configuration)
+- [How it works](#how-it-works)
 - [Roadmap](#roadmap)
 - [Similar projects](#similar-projects)
 
@@ -282,6 +283,12 @@ Example for extended suggestion:
 
 ---
 
+## How it works
+  ![PR-Agent Tools](./pics/pr_agent_overview.png)
+
+Check out the [PR Compression strategy](./PR_COMPRESSION.md) page for more details on how pr-agent works.
+
+
 ## Roadmap
 
 - [ ] Support open-source models, as a replacement for openai models. Note that a minimal requirement for each open-source model is to have 8k+ context, and good support for generating json as an output