Iago-lito <iago-lito@xxxxxxx> writes: > Hello, > > I have troubles understanding the behaviour of `git apply` with respect to renames in a `--no-index` context. > > Let us craft a toy folder: > ```sh > $ mkdir x > $ echo a > x/a # To be modified. > $ echo b > x/b # To be renamed. > ``` > > Duplicate it twice to get three identical folders `x = y = z`. > > ```sh > $ cp -r x y > $ cp -r x z > ``` > > Modify `y`: > ```sh > $ echo newline >> y/a # Edit. > $ mv y/b y/c # Rename. > ``` > > Now I would like to use git as a "better GNU patch". > Calculate the diff from `x` to `y`: > ```sh > $ git diff --no-prefix x y | tee patch > diff --git x/a y/a > index 7898192..4030aa5 100644 > --- x/a > +++ y/a > @@ -1 +1,2 @@ > a > +newline > diff --git x/b y/c > similarity index 100% > rename from x/b > rename to y/c > ``` Interesting. I think "git diff --no-index" is "wrong" here, but "wrong" is not in the sense that it is _incorrect_, but in the sense that it merely is incompatible with what you are trying to achieve. If you had files a and b, modified a in place and renamed b to c, and if you did this in a repository with tracked files, you would have seen $ git diff --src-prefix=x --dst-prefix=y diff --git x/a y/a index ... --- x/a +++ y/a ... diff --git x/b y/c similarity index 100% rename from b rename to c Notice how "rename from" and "rename to" information is different in the "real" git-diff output, as opposed to "git diff --no-index" output you have? At least when comparing two directories, "git diff --no-index X Y" could be interpreted as a request to treat as if X and Y were checkouts from two Git commits X and Y, and by comparing them the output should be identical to the result of comparing the contents of commits X and Y. But feeding "git apply" however may not be the only reason why people are using "diff --no-index X Y", and there may be a legitimate reason why peole want to see "from x/b to y/c" in the output, so unconditionally changing the output may very likely break workflows of other people.
