mailmap: add list of contributors

Since a number of contributors to DPDK have submitted patches to DPDK
under more than one email address, we should maintain a mailmap file
to properly track their commits using "shortlog",
and to do accurate automatic Cc with "get_maintainer.pl".

It also helps fix up any mangled names, for example, with
surname/firstname reversed, or with incorrect capitalization.
By keeping this file in the DPDK repository,
rather than committers maintaining their own copies,
it allows individual contributors to edit it
to update their own email address preferences if so desired.

While at it, update our checkpatches.sh script
and add some documentation to help new contributors.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>

MAINTAINERS

@@ -103,6 +103,7 @@ F: devtools/libabigail.abignore
 F: devtools/words-case.txt
 F: license/
 F: .editorconfig
+F: .mailmap
 
 Build System
 M: Bruce Richardson <bruce.richardson@intel.com>

devtools/check-spdx-tag.sh

@@ -20,7 +20,7 @@ check_spdx() {
 	echo "--------------------------"
     fi
     git grep -L SPDX-License-Identifier -- \
-	':^.git*' ':^.ci/*' ':^.travis.yml' \
+	':^.git*' ':^.mailmap' ':^.ci/*' ':^.travis.yml' \
 	':^README' ':^MAINTAINERS' ':^VERSION' ':^ABI_VERSION' \
 	':^*/Kbuild' ':^*/README' \
 	':^license/' ':^config/' ':^buildtools/' ':^*/poetry.lock' \

devtools/checkpatches.sh

@@ -248,6 +248,28 @@ check_release_notes() { # <patch>
 		grep -v $current_rel_notes
 }
 
+check_names() { # <patch>
+	res=0
+
+	old_IFS=$IFS
+	IFS='
+'
+	for contributor in $(sed -rn '1,/^--- / {s/.*: (.*<.*@.*>)/\1/p}' $1); do
+		! grep -qE "^$contributor($| <)" .mailmap || continue
+		name=${contributor%% <*}
+		if grep -q "^$name <" .mailmap; then
+			reason="$name mail differs from primary mail"
+		else
+			reason="$contributor is unknown"
+		fi
+		echo "$reason, please fix the commit message or update .mailmap."
+		res=1
+	done
+	IFS=$old_IFS
+
+	return $res
+}
+
 number=0
 range='origin/main..'
 quiet=false
@@ -356,6 +378,14 @@ check () { # <patch-file> <commit>
 		ret=1
 	fi
 
+	! $verbose || printf '\nChecking names in commit log:\n'
+	report=$(check_names "$tmpinput")
+	if [ $? -ne 0 ] ; then
+		$headline_printed || print_headline "$subject"
+		printf '%s\n' "$report"
+		ret=1
+	fi
+
 	if [ "$tmpinput" != "$1" ]; then
 		rm -f "$tmpinput"
 		trap - INT

doc/guides/contributing/patches.rst

@@ -148,6 +148,12 @@ Make your planned changes in the cloned ``dpdk`` repo. Here are some guidelines
 
 * Follow the :ref:`coding_style` guidelines.
 
+* If you are a new contributor, or if your mail address changed,
+  you may update the ``.mailmap`` file.
+  Otherwise the new name or address will be added by a maintainer.
+  Keeping this file up-to-date will help when someone wants to contact you
+  about the changes you contributed to.
+
 * If you add new files or directories you should add your name to the ``MAINTAINERS`` file.
 
 * Initial submission of new PMDs should be prepared against a corresponding repo.