fix: resolve Docker performance issues on Windows

.dockerignore

@@ -1,6 +1,7 @@
 # Version control
 .git
 .gitignore
+.worktrees
 
 # Environment secrets — NEVER include in build context
 .env
@@ -19,7 +20,8 @@ node_modules
 *.swp
 *.swo
 
-# Documentation and tests (not needed in production image)
+# Documentation and tests (not needed in built images)
+# Note: test/ is synced into the dev container at runtime via `docker compose watch`.
 docs/
 test/
 *.md

.gitattributes

@@ -10,7 +10,8 @@
 *.toml  text eol=lf
 
 # Shell scripts — LF
-*.sh    text eol=lf
+*.sh          text eol=lf
+.husky/*      text eol=lf
 
 # Windows scripts — CRLF
 *.bat   text eol=crlf

.husky/pre-commit

@@ -1 +1,2 @@
+#!/bin/sh
 mix compile --warnings-as-errors && mix format --check-formatted && mix credo --strict

Dockerfile.dev

@@ -1,4 +1,5 @@
-# Development Dockerfile — source code is bind-mounted, not copied
+# Development Dockerfile — source is baked in at build time; changes are synced
+# at runtime via `docker compose watch` (avoids slow Windows bind-mount I/O).
 FROM elixir:1.18-otp-28-alpine
 
 RUN apk add --no-cache git build-base inotify-tools nodejs npm
@@ -7,6 +8,10 @@ WORKDIR /app
 
 RUN mix local.hex --force && mix local.rebar --force
 
+# Bake source into the image layer. deps/_build/node_modules are excluded by
+# .dockerignore and will be populated into named volumes at container start.
+COPY . .
+
 EXPOSE 4000
 
 CMD ["mix", "phx.server"]

config/dev.exs

@@ -104,5 +104,8 @@ config :phoenix_live_view,
   # Changing this configuration will require mix clean and a full recompile.
   debug_heex_annotations: true,
   debug_attributes: true,
-  # Enable helpful, but potentially expensive runtime checks
-  enable_expensive_runtime_checks: true
+  # Enable helpful, but potentially expensive runtime checks.
+  # Set PHX_EXPENSIVE_CHECKS=false (e.g. in docker-compose.dev.yml) to turn
+  # these off in constrained environments like Docker on Windows where they
+  # noticeably slow down LiveView renders.
+  enable_expensive_runtime_checks: System.get_env("PHX_EXPENSIVE_CHECKS", "true") == "true"

docker-compose.dev.yml

@@ -58,20 +58,66 @@ services:
       DB_PORT: "5432"
       SMTP_HOST: mailpit
       PHX_IP: "0.0.0.0"
+      # Disable BEAM scheduler busy-waiting. By default idle schedulers spin on
+      # their vCPU rather than sleeping, starving other threads in WSL2's shared
+      # VM environment and adding latency to every request.
+      ERL_FLAGS: "+sbwt none +sbwtdcpu none +sbwtdio none"
+      # Disable expensive LiveView runtime checks (assign validation, slot checks,
+      # etc.) which add overhead on every render cycle — too costly in Docker on Windows.
+      PHX_EXPENSIVE_CHECKS: "false"
     volumes:
-      - .:/app
+      # No Windows bind-mount for source — use `docker compose watch` instead.
+      # deps/_build/node_modules stay as named volumes for fast recompilation.
       - deps:/app/deps
       - build:/app/_build
       - node_modules:/app/assets/node_modules
+    develop:
+      watch:
+        # Sync Elixir source, config, migrations, and static assets into the
+        # container via Docker's internal protocol — bypasses the slow WSL2↔Windows
+        # filesystem bridge that makes `- .:/app` bind-mounts sluggish on Windows.
+        - action: sync
+          path: lib
+          target: /app/lib
+        - action: sync
+          path: config
+          target: /app/config
+        - action: sync
+          path: priv
+          target: /app/priv
+          ignore:
+            # Tailwind/esbuild compile into priv/static/assets/ inside the
+            # container. Syncing the host copy (which may be stale or absent)
+            # would overwrite freshly-built CSS/JS with wrong files.
+            - static/assets/
+        - action: sync
+          path: test
+          target: /app/test
+        - action: sync
+          path: assets
+          target: /app/assets
+          ignore:
+            - node_modules/
+        # Dependency or tooling changes require a full image rebuild.
+        - action: rebuild
+          path: mix.exs
+        - action: rebuild
+          path: mix.lock
+        - action: rebuild
+          path: assets/package.json
+        - action: rebuild
+          path: assets/package-lock.json
     depends_on:
       postgres:
         condition: service_healthy
     command: >
       sh -c "
         mix deps.get &&
+        mix assets.vendor &&
         cd assets && npm install && cd .. &&
         mix tailwind.install --if-missing &&
         mix esbuild.install --if-missing &&
+        mix assets.build &&
         mix ecto.create &&
         mix ecto.migrate &&
         exec mix phx.server