Re: Need help merging unrelated histories

[Philip Oakley <philipoakley@iee.org>]

Hi Robert,
A few comments to look at, which may help.
On 28/05/2019 19:26, Robert Dailey wrote:
> On Tue, May 28, 2019 at 8:35 AM Robert Dailey <rcdailey.lists@gmail.com> wrote:
>> On Fri, May 24, 2019 at 12:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
>>> On Mai 24 2019, Robert Dailey <rcdailey.lists@gmail.com> wrote:
>>>
>>>> Can anyone provide some advice on how to properly restructure this
>>>> repository to create some ancestry, as if all along a `master` existed
>>>> and all release branches were based on this in a linear fashion?
>>> How about using git replace --graft, then git filter-branch to make it
>>> permanent?
>> I unfortunately have little-to-no experience with low level plumbing
>> commands. Could you provide an example of a series of commands to run?
>> It will help me to figure out how to do it on my own for my specific
>> use case. Thanks in advance.
> Toyed around with it a bit, and tried with the script below. There
> were no errors, but I noticed that it erased my `.gitattributes` file
> on master that I committed before performing the graft. Why did it
> remove the file? I assume I'm not doing this correctly. Please advise.
> Thank you.
>
> ```sh
> #!/usr/bin/env bash
> set -ex
>
> if [[ ! -d Native_SDK.git ]]; then
>      git clone --bare git@github.com:powervr-graphics/Native_SDK.git
> else
>      cd Native_SDK.git
>      git fetch
>      cd -
> fi
>
> rm -rf test_repo
> git clone Native_SDK.git test_repo
> cd test_repo
>
> git checkout -f --orphan new_master
Check here what is in the files system and index - see the caveat in the 
man page for the --orphan start point and potential use of `git rm -rf .`
> echo '* text=auto' > .gitattributes
Maybe also add some mega comment line to really see it..
> git add .gitattributes
> git commit -m 'Add gitattributes file'
Check what is actually committed, in case you have more/less than expected.
> c=$(git log --oneline origin/3.4 | tail -1 | cut -d ' ' -f 1)
Is this the one you expected (maybe gitk viewer )
> git replace --graft $c new_master
Typing "git replace" without arguments, also lists all replace refs. - 
check what the new one is. Investigate.
> git filter-branch HEAD..origin/3.4
Hmm is this the right range for re-write (not checked, just feels as if 
it's wrong). Maybe also need a local branch name for origin/3.4, just 
for comparing.
> git merge --no-edit --no-ff origin/3.4
> ```
same again

Hopefully the random thoughts may prompt something.
Philip