how to fix the problem correctly?

I have a following situation (in dev branch):

3 files: 1.txt, 2.txt, 3.txt

A -> B -> C -> D -> E
        |                     |
   Master               dev

Between B and C the version of file 1.txt was screwed up (let’s say it was copied into git repo from other location where it was in state A (CVS) and then committed by mistake in C, effectively reverting the change of this file in commit B) Commit C also had changes to files 2 and 3. After this commits D and E did not have changes for file 1.txt, only 2 and 3 were touched.

When we tried to revert commit C – this lead to the code completely messed up, with conflicts – so this seems to be not an option. Rebase also doesn’t seem to help here

Only two variants I saw:
1. Do “git co A 1.txt” and commit the change as F
2. Do “git reset –soft master” and recommit all changes once again

Is there a better way?

PS interesting enough – CVS keywords helped us to notice the problem as master state was imported from CVS. In commit A file 1.txt had version ID 1.5 in commit B it was 1.6 , commit C was changing the line back to 1.5 Is there a way for git to help me to recognize this kind of issue if there are no keywords?

DISCLAIMER: I don’t like keywords, and I don’t want them to be
implemented in git.

Thanks, Eugene