A script to use with git bisect run, to automatically find a bad revision of a project using sbt

bisect-test.sh

#!/usr/bin/env sh
# requires: GNU timeout
# code 0 if the current source code is good/old
# code between 1 and 127 (inclusive), except 125, if the current source code is bad/new.
# code 125 should be used when the current source code cannot be tested.
# see https://git-scm.com/docs/git-bisect
#
# Use (after you copied this to bisect-test.sh _outside_ your repository):
# 
# git reset --hard
# git bisect reset
# git bisect start
# git bisect good <a good revision>
# git bisect bad <a bad revision>
# chmod u+x ../bisect-test.sh
# rm "$HOME/tmp/bisect.log"
# git bisect run ../bisect-test.sh

LOG_FILE="$HOME/tmp/bisect.log"
SBT_CMD="sbt --batch --supershell=never --color=always"
COMMAND_LOAD_BUILD="exit"
COMMAND_COMPILE="compile"
COMMAND_GOOD_BAD="testOnly tests/test_encoder_block.py"
TIMEOUT_LOAD_BUILD="30"
TIMEOUT_COMPILE="60"
TIMEOUT_GOOD_BAD="300"

# Setup
(./install-sbt.sh)
. ./env/bin/activate
. ./.env
export PATH="$(pwd)/target/tools/sbt/bin:$PATH"
export SBT_OPTS="$SBT_OPTS -Xmx512M -Xms512M"
export SBT_OPTS="$SBT_OPTS -Djline.terminal=jline.UnsupportedTerminal"


log() {
  echo "\e[7m$1\e[0m" >&2
  echo "$1" >> "$LOG_FILE"
}

GL=$(git log -1 --pretty=medium)
log "\nNow evaluating:\n$GL"

narrow_down_cause() {
  timeout "$TIMEOUT_LOAD_BUILD" $SBT_CMD "$COMMAND_LOAD_BUILD"
  case $? in
    124) # the exit code timeout uses to signal that a timeout occurred
      log "Ran into timeout loading the build. Telling git to skip."
      sleep 1
      git reset --hard
      exit 125
      ;;

    0)
      log "Build loaded OK. Checking if failure was due to a failed compilation…"
      narrow_down_cause_compile
      ;;

    *)
      log "A problem occurred loading the build. Telling git to skip."
      sleep 1
      git reset --hard
      exit 125
      ;;
  esac
}

narrow_down_cause_compile() {
  timeout "$TIMEOUT_COMPILE" $SBT_CMD "$COMMAND_COMPILE"
  case $? in
    124) # the exit code timeout uses to signal that a timeout occurred
      log "Ran into timeout compiling. Telling git to skip."
      sleep 1
      git reset --hard
      exit 125
      ;;

    0)
      log "Compile finished OK, failure must have been due to tests. Marking revision as bad."
      sleep 1
      git reset --hard
      exit 1
      ;;

    *)
      log "A problem occurred while compiling. Telling git to skip."
      sleep 1
      git reset --hard
      exit 125
      ;;
  esac
}

# Run the command we are actually interested in
timeout "$TIMEOUT_GOOD_BAD" $SBT_CMD "$COMMAND_GOOD_BAD"
case $? in
  124) # the exit code timeout uses to signal that a timeout occurred
    log "Ran into timeout. Telling git to skip."
    git reset --hard
    exit 125
    ;;

  0)
    log "Marking revision as good."
    git reset --hard
    exit 0
    ;;

  *)
    log "An error occurred, narrowing down the cause."
    narrow_down_cause
    ;;
esac