Easy does it

#!/bin/bash

EXP_ERRORS=123

num_errors=$(eslint 2> /dev/null | grep ^src/ | wc -l | awk '$1=$1')
if [ "$num_errors" -gt "$EXP_ERRORS" ];
then
  echo "You added lint errors, please fix them before committing."
  exit 1
else if [ "$num_errors" -lt "$EXP_ERRORS" ];
then
    echo "You fixed lint errors. Great job! Please update EXP_ERRORS in this/script.sh"
    exit 1
fi

name: CI
on:
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review]
defaults:
  run:
    working-directory: ./client
jobs:
  test-base:
    runs-on: gh-hosted-action-runner
    steps:
      - uses: actions/checkout@v4
        with:
          ref: main
          fetch-depth: 2
      - uses: actions/setup-node@v3
        with:
          node-version: "18.17.0"
      - name: Install Yarn
        run: npm i -g yarn
      - name: Install modules
        run: yarn
      # For whatever reason, if I put these commands with a redirect (>)
      # into a script, they don't create the files.
      - name: Create baseline files
        run: |
          npx tsc --noEmit 2> /dev/null | grep ^src/ | wc -l | awk '$1=$1' > ./EXISTING_TSC_ERRORS
          npx eslint --quiet 'src/**/*.{ts,tsx,js,jsx}' src/ 2> /dev/null | grep -E '^[[:space:]]*[0-9]+:[0-9]+[[:space:]]+error' | wc -l | awk '$1=$1' > ./EXISTING_LINT_ERRORS
      - uses: actions/upload-artifact@v3
        with:
          name: EXISTING_TSC_ERRORS
          path: ./client/EXISTING_TSC_ERRORS
      - uses: actions/upload-artifact@v3
        with:
          name: EXISTING_LINT_ERRORS
          path: ./client/EXISTING_LINT_ERRORS
  test-client:
    runs-on: gh-hosted-action-runner
    needs: test-base
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 2
      - uses: actions/setup-node@v3
        with:
          node-version: "18.17.0"      
      - name: Install Yarn
        run: npm i -g yarn
      - name: Install modules
        run: yarn
      - uses: actions/download-artifact@v3
        with:
          name: EXISTING_TSC_ERRORS
          path: ./client
      - uses: actions/download-artifact@v3
        with:
          name: EXISTING_LINT_ERRORS
          path: ./client
      - name: Run typecheck
        run: bash ./scripts/typecheck.sh
      - name: Run tests
        run: yarn test

#!/bin/bash

# Runs the TypeScript compiler (in type-checking mode) and ESLint,
# counts the numbers of errors and exits with a non-zero code if
# the number of errors it higher than acceptable, as defined by
# EXISTING_TSC_ERRORS and EXISTING_LINT_ERRORS artifacts.
#
# The idea is to not add more errors and ideally gradually ratchet
# down existing errors to zero.

exit_code=0

echo -n "tsc... "
num_tsc_errors=$(npx tsc --noEmit 2> /dev/null | grep ^src/ | wc -l | awk '$1=$1')
exp_tsc_errors=$(cat EXISTING_TSC_ERRORS)
if [ "$num_tsc_errors" -gt "$exp_tsc_errors" ];
then
  echo "errors increased from $exp_tsc_errors to $num_tsc_errors."
  exit_code=1
else
  echo "ok"
fi

echo -n "eslint... "
num_eslint_errors=$(npx eslint --quiet 'src/**/*.{ts,tsx,js,jsx}' src/ 2> /dev/null | grep -E '^[[:space:]]*[0-9]+:[0-9]+[[:space:]]+error' | wc -l | awk '$1=$1')
exp_eslint_errors=$(cat EXISTING_LINT_ERRORS)
if [ "$num_eslint_errors" -gt "$exp_eslint_errors" ];
then
  echo "errors increased from $exp_eslint_errors to $num_eslint_errors."
  exit_code=1
else
  echo "ok"
fi

exit $exit_code