tcwg_kernel-bisect.sh: Simplify checking first_bad's parents

Add a quick exit path to the $artifacts/test.sh script, which
simplifies checking of first_bad's parents.  Remove list of
skipped_revs since we are not using it.

Change-Id: I3d8601bafcbf1501239fa5a097830181b327454c

1 files changed, 38 insertions, 48 deletions

diff --git a/tcwg_kernel-bisect.sh b/tcwg_kernel-bisect.sh
index acfc20c2..2bde3c3f 100755
--- a/tcwg_kernel-bisect.sh
+++ b/tcwg_kernel-bisect.sh
@@ -84,9 +84,21 @@ echo "$baseline_rev" >> $artifacts/good_revs
 # skip revisions between rev_20 and rev_22.  This might cause other edge
 # cases to be handled sub-optimally, though.
 cat > $artifacts/test.sh <<EOF
-#!/bin/sh
+#!/bin/bash
+
+set -euf -o pipefail
+
 rev=\$(git rev-parse HEAD)
 cd ..
+
+touch $rel_artifacts/bad_revs $rel_artifacts/good_revs
+
+if grep -q \$rev $rel_artifacts/bad_revs; then
+  exit 1
+elif grep -q \$rev $rel_artifacts/good_revs; then
+  exit 0
+fi
+
 $build_script \
   ^^ $reproduce_bisect \
   %% $rel_artifacts/manifests/build-\$rev.sh \
@@ -95,12 +107,10 @@ $build_script \
   --top_artifacts $rel_artifacts/build-\$rev \
   --verbose "$verbose" &
 res=0 && wait \$! || res=\$?
-if [ -f $rel_artifacts/build-\$rev/failures ]; then
+
+if [ x"\$res" != x"0" ]; then
   echo "\$rev" >> $rel_artifacts/bad_revs
   exit 1
-elif [ x"\$res" != x"0" ]; then
-  echo "\$rev" >> $rel_artifacts/skipped_revs
-  exit 125
 else
   echo "\$rev" >> $rel_artifacts/good_revs
   exit 0
@@ -192,15 +202,8 @@ if [ x"$res" = x"0" ]; then
     first_bad=$(cat .git/BISECT_RUN | head -n 1 | grep "is the first bad commit" | cut -d" " -f 1)
     assert [ x"$first_bad" != x"" ]
 
+    res=0
     for last_good in $(git rev-parse $first_bad^@); do
-	if grep -q $last_good "$artifacts/good_revs"; then
-	    # One of immediate parrents of $first_bad tested good.
-	    break
-	fi
-	last_good=""
-    done
-    if [ x"$last_good" = x"" ]; then
-	# None of immediate parents of $first_bad tested as good.
 	# It seems that git-bisect assumes parent commit as "good" on
 	# the basis of one of its children being "good".  Therefore we
 	# can have a situation when we have parent P with children C1 and C2,
@@ -209,45 +212,32 @@ if [ x"$res" = x"0" ]; then
 	# and it knows CB is "bad", so git-bisect returns C1 as the first bad
 	# commit.
 	# To simplify investigations we explicitly test parent of $first_bad.
-	res=0
-	for last_good in $(git rev-parse $first_bad^@); do
-	    if grep -q $last_good "$artifacts/bad_revs" "$artifacts/skipped_revs"; then
-		echo "First_bad's parent $last_good has tested bad or skipped"
-		last_good=""
-		continue
-	    fi
-	    if [ x"$(git merge-base $merge_base $last_good)" != x"$merge_base" ]; then
-		echo "First_bad's parent $last_good is outside of bisect scope"
-		last_good=""
-		continue
-	    fi
-	    echo "Testing first_bad's parent $last_good (hoping for success)"
-	    git checkout --detach "$last_good"
-	    $artifacts/test.sh &
-	    res=0 && wait $! || res=$?
-	    if [ x"$res" = x"0" ]; then
-		break
-	    fi
-	done
-	if [ x"$res" != x"0" ]; then
-	    # It seems $last_good was on a path that tested good, even though
-	    # it itself is bad.  We re-trigger the bisection job with updated
-	    # parameters.
-	    # We need to be careful to avoid re-trigger loops, so verify that
-	    # last_good is an ancestor of bad_rev.
-	    assert [ x"$(git rev-list $last_good ^$bad_rev)" = x"" ]
-	    cat > $artifacts/trigger-0-bisect-again <<EOF
+	echo "Testing first_bad's parent $last_good (hoping for success)"
+	git checkout --detach "$last_good"
+	$artifacts/test.sh &
+	res=0 && wait $! || res=$?
+	if [ x"$res" = x"0" ]; then
+	    break
+	fi
+    done
+    if [ x"$res" != x"0" ]; then
+	# It seems $last_good was on a path that tested good, even though
+	# it itself is bad.  We re-trigger the bisection job with updated
+	# parameters.
+	# We need to be careful to avoid re-trigger loops, so verify that
+	# last_good is an ancestor of bad_rev.
+	assert git merge-base --is-ancestor $last_good $bad_rev
+	cat > $artifacts/trigger-0-bisect-again <<EOF
 current_project=$current_project
 baseline_rev=$baseline_rev
 bad_rev=$last_good
 EOF
-	    # Don't send any emails.
-	    echo > $artifacts/jenkins/mail-recipients.txt
-	    touch $artifacts/jenkins/build-name
-	    sed -i -e "s/\$/-retry/" $artifacts/jenkins/build-name
-	    trap "" EXIT
-	    exit 0
-	fi
+	# Don't send any emails.
+	echo > $artifacts/jenkins/mail-recipients.txt
+	touch $artifacts/jenkins/build-name
+	sed -i -e "s/\$/-last_good-bad/" $artifacts/jenkins/build-name
+	trap "" EXIT
+	exit 0
     fi
 
     echo $first_bad > $artifacts/first-bad