[RFC] dim: Add warncheck subcommand

[Arkadiusz Hiler]

This subcommand runs 'make W=1' on the provided range.

Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
---
 dim     | 38 ++++++++++++++++++++++++++++++++++++++
 dim.rst |  7 +++++++
 2 files changed, 45 insertions(+)

diff --git a/dim b/dim
index ed26033f5aba..988e83e691c6 100755
--- a/dim
+++ b/dim
@@ -1506,6 +1506,44 @@ function dim_sparse
 	return $rv
 }
 
+function dim_warncheck
+{
+    _restore_head_on_exit
+
+	local range make_output make_rc commits
+
+	range=$(rangeish "${1:-}")
+    commits=( $(git rev-list --reverse $range) )
+
+    git checkout --detach  ${commits[0]}~ > /dev/null 2>&1
+
+    if ! make -j$(nproc) W=1 > /dev/null 2>&1; then
+        echo "The base for the provided range does not build cleanly."
+        echo "Commit: $(git log -n1 --format='%s' HEAD)"
+        echo "Bailing out to cut on the noise."
+        return 1
+    fi
+
+	for commit in "${commits[@]}"; do
+        git checkout --detach $commit >/dev/null 2>&1
+
+        set +e
+        make_output="$(make W=1 2>&1)"
+        make_rc=$?
+        set -e
+
+        if [ "$make_rc" -ne 0 ]; then
+            echo "Commit: $(git log -n1 --format='%s' $commit)"
+            echo "$make_output"
+
+            # error will probably propagate, let's cut the noise
+            echo
+            echo "Quitting early. Please fix and check the other commits as well."
+            return 1
+        fi
+	done
+}
+
 function dim_checker
 {
 	rm -f drivers/gpu/drm/i915/*.o drivers/gpu/drm/i915/*.ko
diff --git a/dim.rst b/dim.rst
index e2c5fd6e6d0a..c73af992243f 100644
--- a/dim.rst
+++ b/dim.rst
@@ -144,6 +144,13 @@ Run sparse on the files changed by the given commit range.
 If no commit-ish is passed, defaults to HEAD^..HEAD. If one commit-ish is passed
 instead of a range, the range commit-ish..HEAD is used.
 
+warncheck [*commit-ish* [.. *commit-ish*]]
+---------------------------------------
+Runs incremental make W=1 on the given commit range.
+
+If no commit-ish is passed, defaults to HEAD^..HEAD. If one commit-ish is passed
+instead of a range, the range commit-ish..HEAD is used.
+
 checker
 -------
 Run sparse on drm/i915.
-- 
2.14.3