Skip to content

UPDATE.md

Latest commit

 

History

History
52 lines (50 loc) · 2.29 KB

UPDATE.md

File metadata and controls

52 lines (50 loc) · 2.29 KB
Raw

sparse update command

Merge Detection

The isMerged function in slice.zig determines whether the current slice (a Git branch reference) has been merged into another branch (into). It uses Git operations to compare commit trees and logs, caching results for efficiency.

Step-by-Step Breakdown

  1. Check Cache If the merge status for the target branch is already cached in _is_merge_into_map, return the cached result.
  2. Quick Object ID Check If the object IDs (commit hashes) of the two branches are the same, return false (no merge check needed).
  3. Find Merge Base Use GitMerge.base to find the common ancestor commit (merge base) between the current slice and the target branch.
  4. Get Trees for Comparison
    • Use git rev-parse to get the tree hash of the merge base.
    • Use git rev-parse to get the tree hash of the current slice.
  5. Get Commit Trees in Target Branch Use git log --format=%T <merge_base>..<into> to get all tree hashes in the target branch since the merge base.
  6. Compare Trees
    • For each tree hash in the log, compare it to the slice’s tree hash.
    • If a match is found, the slice is considered merged. Cache and return true.
    • If no match is found, cache and return false.

High-Level Overview

graph TD
    A[Start isMerged] --> B{Is result cached?}
    B -- Yes --> C[Return cached result]
    B -- No --> D{Are object IDs equal?}
    D -- Yes --> E[Return false]
    D -- No --> F[Find merge base]
    F --> G[Get tree hash of merge base]
    G --> H[Get tree hash of slice]
    H --> I[Get tree hashes in target branch since merge base]
    I --> J{Any tree hash matches slice tree?}
    J -- Yes --> K[Cache & Return true]
    J -- No --> L[Cache & Return false]
Loading

Git Operations Sequence Diagram

sequenceDiagram
    participant Slice
    participant Git
    Slice->>Git: Find merge base (GitMerge.base)
    Slice->>Git: Get merge base tree (git rev-parse <merge_base>^{tree})
    Slice->>Git: Get slice tree (git rev-parse <slice_ref>^{tree})
    Slice->>Git: Get log trees (git log --format=%T <merge_base>..<into>)
    Slice->>Slice: Compare log trees to slice tree
    alt Match found
        Slice->>Slice: Cache & return true
    else No match
        Slice->>Slice: Cache & return false
    end
Loading