[PATCH RFC 5/7] email: add support for X-Aiaiai-Base-Commit

[Jacob Keller]

Allow prospective hooks to detect a base-commit in some manner, instead
of assuming the tip of the tree is the only place to test. This can be
helpful for testing patch re-submissions. Primarly intended for models
where a maintainer keeps a patch-queue branch on which he pushes and
pops patches, so that validation can test them.

Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
---
 doc/email/configuration.txt      |  6 ++++++
 email/aiaiai-email-test-patchset | 12 +++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/doc/email/configuration.txt b/doc/email/configuration.txt
index 9056e0c0fb74..709effea1cba 100644
--- a/doc/email/configuration.txt
+++ b/doc/email/configuration.txt
@@ -192,6 +192,12 @@ to set them, in order to help customize aiaiai.
     default +project from the email address, and could be set in a scenario
     where the project is not specified by address.
 
+* X-Aiaiai-Base-Commit
+    This header tells aiaiai what to use as the base commit, instead of the
+    configured branch. This can be useful if the hook can detect that the patch
+    is a replacement for something already on the tree. This is primarily
+    useful if your work flow uses a patch-queue model.
+
 2.4.1 Dispatcher Hook
 ~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/email/aiaiai-email-test-patchset b/email/aiaiai-email-test-patchset
index cbb5215de94c..3bdc62b4b862 100755
--- a/email/aiaiai-email-test-patchset
+++ b/email/aiaiai-email-test-patchset
@@ -299,11 +299,21 @@ if [ "$pcfg_accept_notify" = "1" ]; then
 	send_accepted_email
 fi
 
+# Use the Base-Commit header if specified, otherwise use the branch
+commit="$(fetch_header "X-Aiaiai-Base-Commit" < "$mbox")"
+if [ -z "$commit" ]; then
+	# Use the default branch
+	commit="$pcfg_branch"
+else
+	# Warn that we are testing against a commit
+	verbose "Found X-Aiaiai-Base-Commit. Testing against $commit."
+fi
+
 # Test the path (or patch-set)
 verbose "Test configs \"$pcfg_configs\" branch \"$pcfg_branch\" of \"$pcfg_path\""
 aiaiai-test-patchset $verbose ${cfg_preserve_files:+--preserve} \
 	${pcfg_targets:+--targets "$pcfg_targets"} $bisectability $sparse $smatch $cppcheck $coccinelle \
-	-i "$mbox" -j "$cfg_jobs" -c "$pcfg_branch" -w "$tmpdir" \
+	-i "$mbox" -j "$cfg_jobs" -c "$commit" -w "$tmpdir" \
 	${pcfg_defconfigdir:+-C "$pcfg_defconfigdir"} \
 	${pcfg_unwanted_keywords:+-K "$pcfg_unwanted_keywords"} \
 	${pcfg_kmake_opts:+-M "$pcfg_kmake_opts"} -- \
-- 
1.8.3.1