"Variable FILES is empty." if one renames the data/... file

[probonopd]

"Variable FILES is empty." if one renames the data/... file.
It seems like our detection of which file was changed doesn't handle renames properly.

Example: #3141

[probonopd]

We've been using

FILES=$(git log -1 -p data/ | grep +++ | cut -d '/' -f 2-| sed -e 's|dev/null||g')

How do we need to change this so that renames are also caught?

Would this be a good approach?

FILES=$(git diff --name-status -1 --diff-filter=AR -- data/ | awk '{print $2}')

[probonopd]

Maybe better:

# Most recent addition or renaming within the last 10 commits
FILES=$(git log -10 --name-status --diff-filter=AR --pretty=format: -- data/ | awk '/^A/ || /^R/ {file=$2} END {print file}')

[probonopd]

No... the last one finds wrong files in PRs...

[probonopd]

Argh. These tend to find the wrong files in PRs.

E.g., e8a0914 in #3122 tested a file unrelated to the PR.

Why? Reverting for now.

[probonopd]

Maybe @andy5995 has an idea?

[probonopd]

Maybe related to #2595

[andy5995]

Maybe add --follow to the git log command?

--follow
Continue listing the history of a file beyond renames (works only for a single file).

[andy5995]

Also available with git log:

-M[<n>], --find-renames[=<n>]
           If generating diffs, detect and report renames for each commit. For following files
           across renames while traversing history, see --follow. If n is specified, it is a
           threshold on the similarity index (i.e. amount of addition/deletions compared to the
           file’s size). For example, -M90% means Git should consider a delete/add pair to be a
           rename if more than 90% of the file hasn’t changed. Without a % sign, the number is to
           be read as a fraction, with a decimal point before it. I.e., -M5 becomes 0.5, and is
           thus the same as -M50%. Similarly, -M05 is the same as -M5%. To limit detection to
           exact renames, use -M100%. The default similarity index is 50%.

and

       --summary
           Output a condensed summary of extended header information such as creations, renames and mode changes.

and this one it looks like you've already tried

       --diff-filter=[(A|C|D|M|R|T|U|X|B)...[*]]
           Select only files that are Added (A), Copied (C), Deleted (D), Modified (M), Renamed (R), have their type
           (i.e. regular file, symlink, submodule, ...) changed (T), are Unmerged (U), are Unknown (X), or have had
           their pairing Broken (B). Any combination of the filter characters (including none) can be used. When *
           (All-or-none) is added to the combination, all paths are selected if there is any file that matches other
           criteria in the comparison; if there is no file that matches other criteria, nothing is selected.

[probonopd]

Maybe we need to touch renamed files.

If someone knows a better solution, please let me know.