Script to identify the code owner for given files

Can be used with git diff --name-only to identify owners for changes
in given commits.

1 files changed, 79 insertions, 0 deletions

diff --git a/dev/tools/check-owners.sh b/dev/tools/check-owners.sh
new file mode 100755
index 000000000..c3c545d6d
--- /dev/null
+++ b/dev/tools/check-owners.sh
@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+
+# Determine CODEOWNERS of the files given in argument
+# For a given commit range:
+# git diff --name-only -z COMMIT1 COMMIT2 | xargs -0 dev/tools/check-owners.sh
+
+# NB: gitignore files will be messed up if you interrupt the script.
+# You should be able to just move the .gitignore.bak files back manually.
+
+if [ $# = 0 ]; then
+    >&2 echo "usage: $0 [FILE]..."
+    exit 1
+fi
+
+if ! [ -e .github/CODEOWNERS ]; then
+    >&2 echo "No CODEOWNERS set up or calling from wrong directory."
+    exit 1
+fi
+
+# CODEOWNERS uses .gitignore patterns so we want to use git to parse it
+# The only available tool for that is git check-ignore
+# However it provides no way to use alternate .gitignore files
+# so we rename them temporarily
+
+find . -name .gitignore -print0 | while IFS= read -r -d '' f; do
+    if [ -e "$f.bak" ]; then
+        >&2 echo "$f.bak exists!"
+        exit 1
+    else
+        mv "$f" "$f.bak"
+    fi
+done
+
+# CODEOWNERS is not quite .gitignore patterns:
+# after the pattern is the owner (space separated)
+# git would interpret that as a big pattern containing spaces
+# so we create a valid .gitignore by removing all but the first field
+
+while read -r pat _; do
+    printf "%s\n" "$pat" >> .gitignore
+done < .github/CODEOWNERS
+
+# associative array [file => owner]
+declare -A owners
+
+for f in "$@"; do
+    data=$(git check-ignore --verbose --no-index "./$f")
+    code=$?
+
+    if [[ "$code" = 1 ]] || ! [[ "$data" =~ .gitignore:.* ]] ; then
+        # no match, or match from non tracked gitignore (eg global gitignore)
+        owners[$f]="Nobody"
+    else
+        # data looks like [.gitignore:$line:$pattern $file]
+        # extract the line to look it up in CODEOWNERS
+        data=${data#'.gitignore:'}
+        data=${data%%:*}
+
+        # NB: supports multiple owners
+        # Does not support secondary owners declared in comment
+        read -r _ fowners < <(sed "${data}q;d" .github/CODEOWNERS)
+        owners["$f"]="$fowners"
+    fi
+done
+
+for f in "${!owners[@]}"; do
+    printf "%s: %s\n" "$f" "${owners[$f]}"
+done | sort -k 2 -k 1 # group by owner
+
+# restort gitignore files
+rm .gitignore
+find . -name .gitignore.bak -print0 | while IFS= read -r -d '' f; do
+    base=${f%.bak}
+    if [ -e "$base" ]; then
+        >&2 echo "$base exists!"
+    else
+        mv "$f" "$base"
+    fi
+done