diff --git a/.github/workflows/integration-tests.yml b/.github/workflows/integration-tests.yml
index da229b1ec8..d0ecb860d0 100644
--- a/.github/workflows/integration-tests.yml
+++ b/.github/workflows/integration-tests.yml
@@ -150,11 +150,12 @@ jobs:
       - name: yalc publish for react-on-rails
         run: cd packages/react-on-rails && yalc publish
       - name: yalc add react-on-rails
-        run: cd react_on_rails/spec/dummy && yalc add react-on-rails
+        # Use --link to maintain the link: protocol that matches pnpm-lock.yaml
+        run: cd react_on_rails/spec/dummy && yalc add --link react-on-rails
       - name: Install Node modules with pnpm for dummy app
         # --ignore-workspace prevents pnpm from treating this as part of the parent workspace
-        # The dummy app doesn't have a pnpm-lock.yaml and shouldn't use frozen lockfile
-        run: cd react_on_rails/spec/dummy && pnpm install --ignore-workspace
+        # minimum config changes package.json (shakapacker version), so can't use frozen lockfile
+        run: cd react_on_rails/spec/dummy && pnpm install --ignore-workspace ${{ matrix.dependency-level == 'minimum' && '--no-frozen-lockfile' || '' }}
       - name: Save dummy app ruby gems to cache
         uses: actions/cache@v4
         with:
@@ -256,11 +257,12 @@ jobs:
       - name: yalc publish for react-on-rails
         run: cd packages/react-on-rails && yalc publish
       - name: yalc add react-on-rails
-        run: cd react_on_rails/spec/dummy && yalc add react-on-rails
+        # Use --link to maintain the link: protocol that matches pnpm-lock.yaml
+        run: cd react_on_rails/spec/dummy && yalc add --link react-on-rails
       - name: Install Node modules with pnpm for dummy app
         # --ignore-workspace prevents pnpm from treating this as part of the parent workspace
-        # The dummy app doesn't have a pnpm-lock.yaml and shouldn't use frozen lockfile
-        run: cd react_on_rails/spec/dummy && pnpm install --ignore-workspace
+        # minimum config changes package.json (shakapacker version), so can't use frozen lockfile
+        run: cd react_on_rails/spec/dummy && pnpm install --ignore-workspace ${{ matrix.dependency-level == 'minimum' && '--no-frozen-lockfile' || '' }}
       - name: Dummy JS tests
         run: |
           cd react_on_rails/spec/dummy
diff --git a/.github/workflows/lint-js-and-ruby.yml b/.github/workflows/lint-js-and-ruby.yml
index 8734a695ec..3e2ef20089 100644
--- a/.github/workflows/lint-js-and-ruby.yml
+++ b/.github/workflows/lint-js-and-ruby.yml
@@ -132,7 +132,8 @@ jobs:
       - name: yalc publish for react-on-rails
         run: cd packages/react-on-rails && yalc publish
       - name: yalc add react-on-rails
-        run: cd react_on_rails/spec/dummy && yalc add react-on-rails
+        # Use --link to maintain the link: protocol that matches pnpm-lock.yaml
+        run: cd react_on_rails/spec/dummy && yalc add --link react-on-rails
       - name: Install Node modules with pnpm for dummy app
         # --ignore-workspace prevents pnpm from treating this as part of the parent workspace
         # The dummy app has its own dependencies and uses yalc links
diff --git a/.github/workflows/precompile-check.yml b/.github/workflows/precompile-check.yml
new file mode 100644
index 0000000000..d88d26e91d
--- /dev/null
+++ b/.github/workflows/precompile-check.yml
@@ -0,0 +1,172 @@
+name: Assets Precompile Check
+
+on:
+  push:
+    branches:
+      - 'master'
+  pull_request:
+    paths-ignore:
+      - '**.md'
+      - 'docs/**'
+      - 'react_on_rails_pro/**'
+  workflow_dispatch:
+    inputs:
+      force_run:
+        description: 'Force run all jobs (bypass detect-changes)'
+        required: false
+        type: boolean
+        default: false
+
+jobs:
+  detect-changes:
+    permissions:
+      contents: read
+      actions: read
+    runs-on: ubuntu-22.04
+    outputs:
+      docs_only: ${{ steps.detect.outputs.docs_only }}
+      run_dummy_tests: ${{ steps.detect.outputs.run_dummy_tests }}
+      has_full_ci_label: ${{ steps.check-label.outputs.result }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 50
+          persist-credentials: false
+      - name: Check for full-ci label
+        id: check-label
+        uses: ./.github/actions/check-full-ci-label
+      - name: Detect relevant changes
+        id: detect
+        run: |
+          if [ "${{ inputs.force_run }}" = "true" ] || [ "${{ steps.check-label.outputs.result }}" = "true" ]; then
+            echo "run_dummy_tests=true" >> "$GITHUB_OUTPUT"
+            echo "docs_only=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          BASE_REF="${{ github.event.pull_request.base.sha || github.event.before || 'origin/master' }}"
+          script/ci-changes-detector "$BASE_REF"
+        shell: bash
+      - name: Guard docs-only master pushes
+        if: github.event_name == 'push' && github.ref == 'refs/heads/master'
+        uses: ./.github/actions/ensure-master-docs-safety
+        with:
+          docs-only: ${{ steps.detect.outputs.docs_only }}
+          previous-sha: ${{ github.event.before }}
+
+  precompile-check:
+    needs: detect-changes
+    # Skip only if: master push AND docs-only changes
+    # Otherwise run if: on master OR workflow_dispatch OR dummy tests needed
+    if: |
+      !(
+        github.event_name == 'push' &&
+        github.ref == 'refs/heads/master' &&
+        needs.detect-changes.outputs.docs_only == 'true'
+      ) && (
+        github.ref == 'refs/heads/master' ||
+        github.event_name == 'workflow_dispatch' ||
+        needs.detect-changes.outputs.run_dummy_tests == 'true'
+      )
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.4'
+          bundler: 2.5.9
+      # libyaml-dev is needed for psych v5
+      - name: Fix dependency for libyaml-dev
+        run: sudo apt install libyaml-dev
+      - name: Setup Node
+        uses: ./.github/actions/setup-node-with-retry
+        with:
+          node-version: '22'
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+      - name: Get pnpm store directory
+        shell: bash
+        run: echo "STORE_PATH=$(pnpm store path --silent)" >> "$GITHUB_ENV"
+      - name: Setup pnpm cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ env.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-store-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-pnpm-store-
+      - name: Print system information
+        run: |
+          echo "Linux release: "; cat /etc/issue
+          echo "Current user: "; whoami
+          echo "Current directory: "; pwd
+          echo "Ruby version: "; ruby -v
+          echo "Node version: "; node -v
+          echo "pnpm version: "; pnpm --version
+          echo "Bundler version: "; bundle --version
+      - name: Install Node modules with pnpm for renderer package
+        run: |
+          pnpm install --frozen-lockfile
+          pnpm add -g yalc
+      - name: yalc publish for react-on-rails
+        run: cd packages/react-on-rails && yalc publish
+      - name: yalc add react-on-rails
+        run: cd react_on_rails/spec/dummy && yalc add react-on-rails
+      - name: Install Node modules with pnpm for dummy app
+        # --ignore-workspace prevents pnpm from treating this as part of the parent workspace
+        # The dummy app doesn't have a pnpm-lock.yaml
+        run: cd react_on_rails/spec/dummy && pnpm install --ignore-workspace
+      - name: Save dummy app ruby gems to cache
+        uses: actions/cache@v4
+        with:
+          path: react_on_rails/spec/dummy/vendor/bundle
+          key: dummy-app-gem-cache-${{ hashFiles('react_on_rails/spec/dummy/Gemfile.lock') }}-precompile
+      - name: Install Ruby Gems for dummy app
+        run: |
+          cd react_on_rails/spec/dummy
+          bundle lock --add-platform 'x86_64-linux'
+          if ! bundle check --path=vendor/bundle; then
+            bundle _2.5.9_ install --path=vendor/bundle --jobs=4 --retry=3
+          fi
+      - name: Build ReScript files
+        run: cd react_on_rails/spec/dummy && pnpm run build:rescript
+      - name: Generate file system-based packs
+        run: cd react_on_rails/spec/dummy && RAILS_ENV=production bundle exec rake react_on_rails:generate_packs
+      - name: Clean compiled assets
+        # Clobber removes both Sprockets assets (public/assets) and webpack output (public/webpack)
+        # This ensures we test a fresh build, not cached "Everything's up-to-date" output
+        run: cd react_on_rails/spec/dummy && RAILS_ENV=production bundle exec rake assets:clobber
+      - name: Run assets:precompile and capture output
+        # Timeout prevents hung webpack processes from running for 6 hours.
+        # Typical precompile takes 2-5 minutes; 15 minutes is generous.
+        timeout-minutes: 15
+        run: |
+          cd react_on_rails/spec/dummy
+
+          echo "Running RAILS_ENV=production bin/rake assets:precompile..."
+          echo "=========================================="
+
+          # Run precompile and capture both stdout and stderr
+          # Use pipefail to catch rake failures even when piped through tee
+          set -o pipefail
+          RAILS_ENV=production bin/rake assets:precompile 2>&1 | tee precompile_output.txt
+          PRECOMPILE_EXIT=${PIPESTATUS[0]}
+
+          echo "=========================================="
+
+          # Check if rake command itself failed
+          if [ "$PRECOMPILE_EXIT" -ne 0 ]; then
+            echo "::error::Precompile command failed with exit code $PRECOMPILE_EXIT"
+            exit "$PRECOMPILE_EXIT"
+          fi
+      - name: Validate precompile output
+        run: script/validate-precompile-output react_on_rails/spec/dummy/precompile_output.txt
+      - name: Upload precompile output
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: precompile-output-${{ github.run_id }}
+          path: react_on_rails/spec/dummy/precompile_output.txt
+          retention-days: 7
diff --git a/script/validate-precompile-output b/script/validate-precompile-output
new file mode 100755
index 0000000000..306633f5ef
--- /dev/null
+++ b/script/validate-precompile-output
@@ -0,0 +1,304 @@
+#!/bin/bash
+#
+# Validates assets:precompile output for known failure patterns.
+#
+# Usage:
+#   script/validate-precompile-output <output_file>
+#
+#   # When piping, MUST use pipefail to catch rake failures:
+#   set -o pipefail
+#   RAILS_ENV=production rake assets:precompile 2>&1 | script/validate-precompile-output -
+#
+#   # Or use tee to capture output and check exit code separately:
+#   RAILS_ENV=production rake assets:precompile 2>&1 | tee output.txt
+#   if [ ${PIPESTATUS[0]} -ne 0 ]; then echo "Rake failed!"; exit 1; fi
+#   script/validate-precompile-output output.txt
+#
+# Exit codes:
+#   0 - All checks passed
+#   1 - One or more failure patterns detected
+#
+# This script checks for known issues that don't cause precompile to fail
+# but indicate bugs like duplicate task execution or missing dependencies.
+#
+# Environment variables:
+#   MIN_EXPECTED_LINES - Minimum lines expected in output (default: 10)
+#   WARNING_THRESHOLD  - Warning count threshold before alerting (default: 20)
+#
+# See: https://github.com/shakacode/react_on_rails/issues/2081
+
+set -e
+
+OUTPUT_FILE="${1:--}"
+
+if [ "$OUTPUT_FILE" = "-" ]; then
+  # Read from stdin to temp file
+  TEMP_FILE=$(mktemp)
+  cat > "$TEMP_FILE"
+  OUTPUT_FILE="$TEMP_FILE"
+  trap 'rm -f "$TEMP_FILE"' EXIT
+fi
+
+if [ ! -f "$OUTPUT_FILE" ]; then
+  echo "Error: Output file '$OUTPUT_FILE' not found"
+  exit 1
+fi
+
+# Check for empty or suspiciously small output
+# A successful precompile produces substantial output (webpack stats, asset listing, etc.)
+# Empty or very small output usually indicates the command failed before producing anything.
+OUTPUT_SIZE=$(wc -c < "$OUTPUT_FILE" | tr -d ' ')
+OUTPUT_LINES=$(wc -l < "$OUTPUT_FILE" | tr -d ' ')
+
+if [ "$OUTPUT_SIZE" -eq 0 ]; then
+  echo "Error: Output file is empty."
+  echo "This usually means the precompile command failed before producing any output."
+  echo "Check that all dependencies are installed (bundle install, pnpm install)."
+  exit 1
+fi
+
+# Minimum expected lines for a successful precompile (webpack output alone is 50+ lines)
+MIN_EXPECTED_LINES="${MIN_EXPECTED_LINES:-10}"
+if [ "$OUTPUT_LINES" -lt "$MIN_EXPECTED_LINES" ]; then
+  echo "Warning: Output file has only $OUTPUT_LINES lines (expected at least $MIN_EXPECTED_LINES)."
+  echo "This may indicate the precompile failed early. Output contents:"
+  echo "---"
+  cat "$OUTPUT_FILE"
+  echo "---"
+  echo ""
+  echo "If this is expected, set MIN_EXPECTED_LINES=0 to disable this check."
+fi
+
+echo "Validating assets:precompile output..."
+echo ""
+
+FAILURES_FOUND=0
+
+# Helper function to report errors (supports GitHub Actions annotations)
+report_error() {
+  local message="$1"
+  if [ -n "$GITHUB_ACTIONS" ]; then
+    echo "::error::$message"
+  else
+    echo "ERROR: $message"
+  fi
+}
+
+# Helper function to report warnings
+report_warning() {
+  local message="$1"
+  if [ -n "$GITHUB_ACTIONS" ]; then
+    echo "::warning::$message"
+  else
+    echo "WARNING: $message"
+  fi
+}
+
+# ==============================================================================
+# Pattern 1: Duplicate webpack compilation (indicates rake tasks running twice)
+# ==============================================================================
+# Prevents: Rails::Engine loading rake tasks twice, causing double webpack builds
+# History: PR #2052 fixed this - Engine's rake_tasks block was explicitly loading
+#          tasks from lib/tasks/, but Rails::Engine already does this automatically.
+# Symptom: "Compiled successfully" appears 2+ times in output, doubling build time.
+# See: https://github.com/shakacode/react_on_rails/pull/2052
+if grep -q "Compiled successfully" "$OUTPUT_FILE"; then
+  COMPILE_SUCCESS_COUNT=$(grep -c "Compiled successfully" "$OUTPUT_FILE" || true)
+  if [ "$COMPILE_SUCCESS_COUNT" -gt 1 ]; then
+    report_error "Detected $COMPILE_SUCCESS_COUNT webpack compilations (expected 1). Tasks may be running twice."
+    echo "  See: https://github.com/shakacode/react_on_rails/pull/2052"
+    echo "  Matching lines:"
+    grep -n "Compiled successfully" "$OUTPUT_FILE" | head -5
+    FAILURES_FOUND=1
+  fi
+fi
+
+# ==============================================================================
+# Pattern 2: Duplicate task execution (react_on_rails rake tasks)
+# ==============================================================================
+# Prevents: Same root cause as Pattern 1 - rake tasks executing twice.
+# Symptom: react_on_rails:generate_packs or react_on_rails:locale appear multiple times.
+# These tasks generate files, so running twice wastes time and may cause issues.
+if grep -q "react_on_rails:generate_packs" "$OUTPUT_FILE"; then
+  GENERATE_PACKS_COUNT=$(grep -c "react_on_rails:generate_packs" "$OUTPUT_FILE" || true)
+  if [ "$GENERATE_PACKS_COUNT" -gt 1 ]; then
+    report_error "react_on_rails:generate_packs task ran $GENERATE_PACKS_COUNT times (should only run once)."
+    echo "  Matching lines:"
+    grep -n "react_on_rails:generate_packs" "$OUTPUT_FILE"
+    FAILURES_FOUND=1
+  fi
+fi
+
+# Pattern 2b: Duplicate locale generation (same root cause as 2a)
+if grep -q "react_on_rails:locale" "$OUTPUT_FILE"; then
+  LOCALE_COUNT=$(grep -c "react_on_rails:locale" "$OUTPUT_FILE" || true)
+  if [ "$LOCALE_COUNT" -gt 1 ]; then
+    report_error "react_on_rails:locale task ran $LOCALE_COUNT times (should only run once)."
+    echo "  Matching lines:"
+    grep -n "react_on_rails:locale" "$OUTPUT_FILE"
+    FAILURES_FOUND=1
+  fi
+fi
+
+# Pattern 2c: Duplicate webpack builds (alternative detection via "Built at:" timestamp)
+# Note: This check complements Pattern 1's "Compiled successfully" check.
+# - "Compiled successfully" is from webpack's stats output (may be absent if build fails)
+# - "Built at:" is webpack's timestamp header (always present even on failed builds)
+# Both are checked to catch duplicates regardless of build success/failure.
+BUILT_AT_COUNT=$(grep -c "Built at:" "$OUTPUT_FILE" || true)
+if [ "$BUILT_AT_COUNT" -gt 1 ]; then
+  report_error "Detected $BUILT_AT_COUNT webpack builds (expected 1). Tasks may be running twice."
+  echo "  Matching lines:"
+  grep -n "Built at:" "$OUTPUT_FILE" | head -5
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 3: Module resolution errors
+# ==============================================================================
+# Prevents: Missing npm packages or incorrect import paths that precompile may not fail on.
+# Important: Uses strict matching to avoid false positives from deprecation warnings
+#            or informational messages that contain similar phrases.
+# Matches webpack's standard format: "Module not found: Error: Can't resolve 'package' in '/path'"
+# Also matches error messages preceded by ERROR or Error: keywords.
+if grep -Ei "(^|\s)(ERROR|Error:).*module not found|(^|\s)(ERROR|Error:).*cannot find module|(^|\s)(ERROR|Error:).*can't resolve|Module not found: Error:" "$OUTPUT_FILE"; then
+  report_error "Module resolution errors detected in precompile output."
+  echo "  Sample matching lines:"
+  grep -Ei "(^|\s)(ERROR|Error:).*module not found|(^|\s)(ERROR|Error:).*cannot find module|(^|\s)(ERROR|Error:).*can't resolve|Module not found: Error:" "$OUTPUT_FILE" | head -3
+  FAILURES_FOUND=1
+fi
+
+# Pattern 3b: ENOENT errors (missing files/directories during build)
+if grep -q "Error: ENOENT" "$OUTPUT_FILE"; then
+  report_error "Missing file or directory errors detected."
+  echo "  Sample matching lines:"
+  grep -n "Error: ENOENT" "$OUTPUT_FILE" | head -3
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 4: Webpack compilation errors
+# ==============================================================================
+# Prevents: Silent webpack build failures that don't cause precompile to exit non-zero.
+# Important: Uses specific error markers to avoid false positives from benign text
+#            like "webpack handles errors gracefully" in documentation or comments.
+# Matches:
+# - "^ERROR in ./": Webpack's standard error format for file-specific errors
+# - "failed to compile": Direct compilation failure message
+# - "COMPILATION FAILED": Shakapacker's explicit failure message (uppercase)
+# - "Module build failed": Loader/build errors (e.g., babel, css-loader failures)
+if grep -Ei "^ERROR in [./]|failed to compile|COMPILATION FAILED|Module build failed" "$OUTPUT_FILE"; then
+  report_error "Webpack compilation errors detected."
+  echo "  Sample matching lines:"
+  grep -Ei "^ERROR in [./]|failed to compile|COMPILATION FAILED|Module build failed" "$OUTPUT_FILE" | head -3
+  # Show context around COMPILATION FAILED for more useful error info
+  if grep -q "COMPILATION FAILED" "$OUTPUT_FILE"; then
+    echo ""
+    echo "  Context around compilation failure:"
+    grep -A 20 "COMPILATION FAILED" "$OUTPUT_FILE" | head -25
+  fi
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 4b: Missing webpack CLI
+# ==============================================================================
+# Prevents: Confusing errors when webpack-cli is not installed.
+# Webpack 5+ requires webpack-cli as a separate dependency.
+# Symptom: "CLI for webpack must be installed" message during compilation.
+if grep -q "CLI for webpack must be installed" "$OUTPUT_FILE"; then
+  report_error "webpack-cli is not installed."
+  echo "  This is a required dependency for webpack builds."
+  echo "  To fix: pnpm add -D webpack-cli"
+  echo "  Or: npm install -D webpack-cli"
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 5: Ruby/Rails errors during precompile
+# ==============================================================================
+# Prevents: Ruby exceptions that are caught/logged but don't fail the rake task.
+# Matches specific exception class names to avoid false positives.
+if grep -E "(NameError|LoadError|NoMethodError|SyntaxError):" "$OUTPUT_FILE"; then
+  report_error "Ruby errors detected during precompile."
+  echo "  Sample matching lines:"
+  grep -E "(NameError|LoadError|NoMethodError|SyntaxError):" "$OUTPUT_FILE" | head -3
+  FAILURES_FOUND=1
+fi
+
+# Pattern 5b: Bundler/Gem errors (missing or version mismatch)
+# Detects errors like "Could not find gem 'shakapacker (= 9.4.0)'"
+# These indicate bundle install wasn't run or Gemfile.lock is out of sync.
+if grep -Ei "Could not find gem|Run \`bundle install\`|Bundler::GemNotFound|Gem::MissingSpecError" "$OUTPUT_FILE"; then
+  report_error "Bundler/gem dependency errors detected."
+  echo "  This usually means 'bundle install' needs to be run."
+  echo "  Sample matching lines:"
+  grep -Ei "Could not find gem|Run \`bundle install\`|Bundler::GemNotFound|Gem::MissingSpecError" "$OUTPUT_FILE" | head -3
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 6: Sprockets/Asset pipeline errors
+# ==============================================================================
+# Prevents: Missing assets that Sprockets can't find or undeclared asset dependencies.
+if grep -Ei "Sprockets::FileNotFound|Asset.*was not declared" "$OUTPUT_FILE"; then
+  report_error "Asset pipeline errors detected."
+  echo "  Sample matching lines:"
+  grep -Ei "Sprockets::FileNotFound|Asset.*was not declared" "$OUTPUT_FILE" | head -3
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 7: Memory issues
+# ==============================================================================
+# Prevents: OOM kills that can happen silently with webpack on large codebases.
+# Uses word boundary (\b) for "Killed" to avoid matching "killed the bug" etc.
+# "Killed" (capital K) is the typical OOM killer message format.
+if grep -Ei "javascript heap out of memory|\bKilled\b|out of memory" "$OUTPUT_FILE"; then
+  report_error "Memory-related errors detected."
+  echo "  Sample matching lines:"
+  grep -Ei "javascript heap out of memory|\bKilled\b|out of memory" "$OUTPUT_FILE" | head -3
+  FAILURES_FOUND=1
+fi
+
+# ==============================================================================
+# Pattern 8: Warning count threshold (advisory, does not fail)
+# ==============================================================================
+# Purpose: Alert when warnings spike, which may indicate new issues worth investigating.
+# Threshold is configurable via WARNING_THRESHOLD env var.
+# Default of 20 chosen based on typical precompile output having ~10-15 benign warnings
+# from node deprecations and peer dependency notices.
+WARNING_THRESHOLD="${WARNING_THRESHOLD:-20}"
+WARNING_COUNT=$(grep -ci "warning" "$OUTPUT_FILE" || true)
+if [ "$WARNING_COUNT" -gt "$WARNING_THRESHOLD" ]; then
+  report_warning "High number of warnings detected: $WARNING_COUNT warnings found (threshold: $WARNING_THRESHOLD). Please review."
+  echo "  Sample warnings:"
+  grep -i "warning" "$OUTPUT_FILE" | head -5
+fi
+
+# ==============================================================================
+# Pattern 9: Deprecation warnings (advisory, does not fail)
+# ==============================================================================
+# Purpose: Track deprecations that may cause future breakage after upgrades.
+# Rails deprecations are logged with "DEPRECATION" prefix.
+DEPRECATION_COUNT=$(grep -c "DEPRECATION" "$OUTPUT_FILE" || true)
+if [ "$DEPRECATION_COUNT" -gt 0 ]; then
+  report_warning "Found $DEPRECATION_COUNT deprecation warnings. These may indicate future breakage."
+  echo "  Deprecation messages:"
+  grep -n "DEPRECATION" "$OUTPUT_FILE" | head -5
+fi
+
+echo ""
+if [ "$FAILURES_FOUND" -eq 1 ]; then
+  echo "=========================================="
+  echo "PRECOMPILE VALIDATION FAILED"
+  echo "=========================================="
+  echo "Review the errors above for details."
+  exit 1
+fi
+
+echo "=========================================="
+echo "PRECOMPILE VALIDATION PASSED"
+echo "=========================================="
+echo "No known failure patterns detected."
+exit 0