Subject: Re: git rename/moved status unreliable in ruby

From: Phillip Wood <[email-masked]>
Date: Fri, 1 May 2026 16:30:16 +0100

Hi Sebastien

On 01/05/2026 06:05, sebastien.stettler wrote:
> 1. What did you do before the bug happened? (Steps to reproduce your issue)
> 
> when moving ruby classes between namespaces they are marked as new files and the old
> ones are marked as deleted
> 
> if i only change the class name it will mark it as renamed

Rename detection is based on how similar the two files are. Looking at 
the example you linked to below you're changing a file that looks like

module Math
   class Calculator
     def add(a, b)
       a + b
       ...
     end
   end
end

to

module Math
   module Calculators
     class Calculator
       def add(a, b)
         a + b
         ...
       end
     end
   end
end

Which means that git sees that every line has changed because the 
indentation has changed. If you want git to realize that the file has 
been renamed you could move it in one commit and then add modify it in 
the next commit.

Thanks

Phillip

> 2. What did you expect to happen? (Expected behavior)
> 
> in the namespace state i would expected it to be marked as moved since
> nothing has fundementally changed
> 
> 3. What happened instead? (Actual behavior)
> 
> the file was marked as new file and the old file was marked as deleted
> 
> What's different between what you expected and what actually happened
> 
> 4. Anything else you want to add:
> 
> I have demonstrated the behavior here https://github.com/billybonks/git-rename
> 
> Mostly i would like to understand what is the expectation from gits point of view in these mutations.
> If this is considered something that can be improved i am happy to build out more test cases, and help with implementation.
> 
> if not, understanding the reasoning would be great
> 
> Thank you.
> 
> 
> 
> [System Info]
> git version:
> git version 2.47.1
> cpu: arm64
> no commit associated with this build
> sizeof-long: 8
> sizeof-size_t: 8
> shell-path: /bin/sh
> feature: fsmonitor--daemon
> libcurl: 8.7.1
> zlib: 1.2.12
> uname: Darwin 25.3.0 Darwin Kernel Version 25.3.0: Wed Jan 28 20:51:28 PST 2026; root:xnu-12377.91.3~2/RELEASE_ARM64_T6041 arm64
> compiler info: clang: 16.0.0 (clang-1600.0.26.4)
> libc info: no libc information available
> $SHELL (typically, interactive shell): /bin/zsh
> 
> 
> [Enabled Hooks]
> 
> 
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