v8/docs/merging_and_patching.md
andybons 6e0cd21569 [Docs] Add wiki content to Markdown docs
NOTE: You will have to land this as I don’t have write perms to this repo.

BUG=none
R=hablich@chromium.org

Review URL: https://codereview.chromium.org/1347153006

Cr-Commit-Position: refs/heads/master@{#30972}
2015-09-28 12:41:25 +00:00

66 lines
2.6 KiB
Markdown

# Introduction
If you have a patch to the master branch (e.g. an important bug fix) that needs to be merged into one of the production V8 branches, read on.
For the examples, a branched 2.4 version of V8 will be used. Substitute "2.4" with your version number.
**An associated issue is mandatory if a patch is merged. This helps with keeping track of merges.**
# Merge process outlined
The merge process in the Chromium and V8 tracker is driven by labels in the form of
```
Merge-[Status]-[Branch]
```
The currently important labels for V8 are:
1. Merge-Request-## initiates the process => This fix should be merged into M-##
1. Merge-Review-## The merge is not approved yet for M-## e.g. because Canary coverage is missing
1. Merge-Approved-## => Simply means that the Chrome TPM are signing the merge off
1. Merge-Merged-$BRANCHNUMBER$ => When the merge is done the Merge-Approved label is swapped with this one. $BRANCHNUMBER$ is the name/number of the V8 branch e.g. 4.3 for M-43.
# Instructions for git using the automated script
## How to check if a commit was already merged/reverted
Use mergeinfo.py to get all the commits which are connected to the HASH according to Git.
```
tools/release/mergeinfo.py HASH
```
## Step 1: Run the script
Let's assume you're merging revision af3cf11 to branch 2.4 (please specify full git hashes - abbreviations are used here for simplicity).
```
tools/release/merge_to_branch.py --branch 2.4 af3cf11
```
Run the script with '-h' to display its help message, which includes more options (e.g. you can specify a file containing your patch, or you can reverse a patch, specify a custom commit message, or resume a merging process you've canceled before). Note that the script will use a temporary checkout of v8 - it won't touch your work space.
You can also merge more than one revision at once, just list them all.
```
tools/release/merge_to_branch.py --branch 2.4 af3cf11 cf33f1b sf3cf09
```
## Step 2: Send a notification letter to hablich@chromium.org
Saying something like this:
```
_Subject:_ Regression fix merged into V8 2.4 branch (Chrome 8)
_Body:_ We have merged a fix to the V8 version 2.4 branch (the version used in Chrome 8)
Version 2.4.9.10: Issue xxx: The parser doesn't parse.
```
# FAQ
## I get an error during merge that is related to tagging. What should I do?
When two people are merging at the same time a race-condition can happen in the merge scripts. If this is the case, contact machenbach@chromium.org and hablich@chromium.org.
## Is there a TL;DR;?
1. Create issue
1. Add Merge-Request-{Branch} to the issue
1. Wait until somebody will add Merge-Approved-{Branch}
1. Merge