If you rename a file, git won’t show history of the previous name:
$ git log --pretty=oneline things/text.txt
8567d... Move file into things directory
However, the --follow flag will allow you to see the history of commits beyond the rename:
$ git log --follow --pretty=oneline things/text.txt
8567d... Move file into things directory
1458a... Fix something
0aac5... Add something
Docs:
--follow
Continue listing the history of a file beyond renames (works only for a single file).