Git Diffing#

Diff working tree vs commit: Use ‘–‘ for working tree e.g. batch>git difftool --dir-diff HEAD --

Diff staged changes vs working directory: batch>git difftool --dir-diff

Diff staged changes vs HEAD: batch>git difftool --dir-diff --staged

Diff across branches:

git difftool 4.17..bebylon -- /d/Ikrima/src/Public-Development/UnrealEngine/Engine/Source/Runtime/Renderer/Private/BasePassRendering.cpp
git difftool --dir-diff release ~HEAD

Folder history diff or folder diff between two different commits batch>git difftool --dir-diff 27990a4451cf9458b280c9be027af41898721791~1 27990a4451cf9458b280c9be027af41898721791

Patch#

Create containing all commits in your current branch that are not in the master branch: batch>git format-patch origin/master --stdout > mypatch.patch

From <https://stackoverflow.com/questions/5432396/create-a-patch-by-comparing-a-specific-branch-on-the-remote-with-a-specific-loca>

GitExtensions: filter a set of branches Bebylon* –remotes=upstream/release* –remotes=upstream/dev*

Diff tool config:

Araxis config:

[difftool "araxis"]
path = C:\\Program Files\\Araxis\\Araxis Merge\\compare.exe

[mergetool "Araxis"]
path = C:/Program Files/Araxis/Araxis Merge/Compare.exe
cmd = \"C:/Program Files/Araxis/Araxis Merge/Compare.exe\" \"$REMOTE\" \"$BASE\" \"$LOCAL\" \"$MERGED\"

Merge with force accept theirs:

Use this commands to do that:

git checkout branch_new
git merge -s ours branch_old
git checkout branch_old
git merge branch_new

From <https://stackoverflow.com/questions/4624357/how-do-i-overwrite-rather-than-merge-a-branch-on-another-branch-in-git>

Remove a folder/file from history: http://stackoverflow.com/questions/10067848/remove-folder-and-its-contents-from-git-githubs-history

https://confluence.atlassian.com/display/BITBUCKET/Maintaining+a+Git+Repository

https://help.github.com/articles/remove-sensitive-data

You want to nuke commit C and never see it again. You do this: batch>git reset --hard HEAD~1

From <http://stackoverflow.com/questions/927358/how-do-you-undo-the-last-commit>

For the lightest touch, you can even undo your commit but leave your files and your index: batch>git reset --soft HEAD~1

From <http://stackoverflow.com/questions/927358/how-do-you-undo-the-last-commit>

Remove all untracked files and directories. (-f is force, -d is remove directories) batch>git clean -fd

Remove ignored files as well batch>git clean -fdx

From <http://stackoverflow.com/questions/5807137/how-to-revert-uncommitted-changes-including-files-and-folders>

Squash/Merge previous two commits: batch>git rebase -i HEAD~2

Then select squash for the second commit From <https://stackoverflow.com/questions/5189560/squash-my-last-x-commits-together-using-git>

To move folders into a different folders in git: git filter-branch --tree-filter 'mkdir -p /path/to/tmp; mv * /path/to/tmp; mkdir subdir; mv /path/to/tmp/* subdir/' --tag-name-filter cat --prune-empty -- --all https://gist.github.com/fabiomaggio/ce7ecd7dffd27b32a45325204288efce

Rebase against another branch overriding conflicts with your own branch changes:

# assuming branch-a is our current version
git rebase -Xtheirs branch-b # <- ours: branch-b, theirs: branch-a

IMPORTANT: -Xtheirs and -Xours is counterintuitive - For rebase: -Xtheirs refers to your local current branch that you want to replay ontop of the master branch. - For merge: -Xours refers to the local branch.

From https://demisx.github.io/git/rebase/2015/07/02/git-rebase-keep-my-branch-changes.html

Git-P4#

TLDR#

You need to use python 2.7
When doing git clone, you have to specify to use client spec git p4 clone //depot/main/BBR/Source . --use-client-spec
You can also exlcude paths and have multiple depot paths
With different directory structures, you can reformat patch files: https://stackoverflow.com/questions/931882/how-to-apply-a-git-patch-from-one-repository-to-another

$ cat patch_file | git am     \
          -p1                 \ # remove 1 leading directory ('static/')
        --directory='lib/'     # prepend 'lib/'

You can also cherry pick commits directly (git will automatically resolve the different path )
Remember to have your git-p4 repo in a separate directory from your actual p4 directory
You can merge unrealted git histories with git merge myotherbranch --allow-unrelated-histories
Use these git config -e settings

[git-p4]
  skipSubmitEdit = true
  useclientspec = true

More Info#

You can use this to sync from perforce to a git and back (it’s brittle)

Links: - https://www.paraesthesia.com/archive/2016/10/27/migrating-perforce-to-git-in-windows/ - https://zzz.buzz/2016/04/30/git-p4-on-windows/ - https://www.atlassian.com/git/tutorials/git-p4

Install instructions#

Needs python 2.7
git config --global alias.p4 !"python 'C:/Program Files (x86)/Git/mingw32/libexec/git-core/git-p4'"

Using#

Set P4 Vars:

set P4PORT=public.perforce.com:1666
set P4USER=yourusername
set P4PASSWD=yourpassword

Clone repo: git p4 clone --detect-branches //depot/perforce_software/p4jenkins
Submit: git p4 submit

Last update: January 8, 2020