Problems with git diff working on command line but not in Python

Question

I'm in the process of writing an application to move commits back and forth between Git and ClearCase repositories.

Git version is: 1.8.3.msysgit.0

The code is written in Python (2.7.5) and I'm getting a wierd error. The behaviour on the command line and the behaviour of the same command in the application are not the same:

From my application's log, I get this::

[git diff --name-status -M -z --ignore-submodules 4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac^..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --] exit code: 128
Command output for [git diff --name-status -M -z --ignore-submodules 4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac^..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --]:
stderr >> fatal: bad revision '4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac^..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac'

However from the same Windows command line, no results, but no error either:

C:\Temp\gitcc_test>git diff --name-status -M -z --ignore-submodules 4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac^..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --

C:\Temp\gitcc_test>

On a similar note, if I run this command line (showing the diffs, not just renamed files), I get output:

C:\Temp\gitcc_test>git diff --ignore-submodules 6a4db18a0048db2dfe0e6639cabcdf10e265a1b6..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --
diff --git a/hello.txt b/hello.txt
index 3eecb7d..da588dd 100644
--- a/hello.txt
+++ b/hello.txt
@@ -1 +1 @@
-Bonjour!
+Hello!

C:\Temp\gitcc_test>

But this command returns nothing:

C:\Temp\gitcc_test>git diff --ignore-submodules 4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac^..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --

C:\Temp\gitcc_test>

The parent commit of 4dc7... is 6a4d..., so why doesn't 4dc7...^ give me any results?

Thanks in advance!

That does look like it should work. I know msysgit has oddities due to Windows (though I don't use Windows so am not sure about the various broken bits), so the first thing I'd try is this: When you give `git diff` the `A..B` syntax it behaves the same as `git diff A B`, so maybe replacing the `A..B` part with two separate arguments will make msysgit behave better. (But that's just a shot in the dark.) — torek, Feb 25 '14 at 17:19
@torek Thanks for the suggestion, I had tried that, and I'm afraid the behaviour is the same. — Chris Cooper, Feb 26 '14 at 15:09

score 0 · Accepted Answer · answered Feb 26 '14 at 15:13

It turns out that not using the '..' and placing the caret at the other end of the hash works a treat on both command line and under Python.

So this:

git diff --name-status -M -z --ignore-submodules 4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac^..4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --

Becomes this:

git diff --name-status -M -z --ignore-submodules ^4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac 4dc7ad29d69ee2385802b262bfb9a4f1e28f10ac --

And everything works a treat!

@lrineau I'll accept it as soon as I am able, there is a time limit on acceptance of your own answer. — Chris Cooper, Feb 27 '14 at 08:08

Problems with git diff working on command line but not in Python

1 Answers1