Add reusable script to refactor Phoenix test conn aliasing

Portable awk-based script that transforms conn shadowing patterns
into idiomatic pipe chains across 4 cases (body extraction, single
assert, pattern match assert, multi-use rename).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

refactor_conn_aliasing.sh

@@ -0,0 +1,188 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  cat <<'EOF'
+Usage: refactor_conn_aliasing.sh [OPTIONS] FILE...
+  --dry-run    Show diff without modifying files
+  --help       Show usage
+EOF
+}
+
+DRY_RUN=false
+FILES=()
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --dry-run) DRY_RUN=true; shift ;;
+    --help)    usage; exit 0 ;;
+    -*)        echo "Unknown option: $1" >&2; usage >&2; exit 1 ;;
+    *)         FILES+=("$1"); shift ;;
+  esac
+done
+
+if [[ ${#FILES[@]} -eq 0 ]]; then
+  echo "Error: no files specified" >&2
+  usage >&2
+  exit 1
+fi
+
+for file in "${FILES[@]}"; do
+  if [[ ! -f "$file" ]]; then
+    echo "Warning: $file not found, skipping" >&2
+    continue
+  fi
+
+  tmpfile=$(mktemp)
+  trap "rm -f '$tmpfile'" EXIT
+
+  awk '
+  # Detect trigger line: conn = VERB(conn, ARGS)
+  # where VERB is get/post/put/patch/delete/head/options
+  /^[[:space:]]*conn = (get|post|put|patch|delete|head|options)\(conn, / {
+    trigger_line = $0
+    # Extract leading whitespace
+    match($0, /^[[:space:]]*/)
+    indent = substr($0, RSTART, RLENGTH)
+
+    # Extract verb and args from: conn = verb(conn, args)
+    rest = $0
+    sub(/^[[:space:]]*conn = /, "", rest)
+    # rest is now: verb(conn, args)
+    paren_pos = index(rest, "(")
+    verb = substr(rest, 1, paren_pos - 1)
+    # args portion: everything after "conn, " up to the trailing ")"
+    inner = substr(rest, paren_pos + 1)
+    sub(/\)$/, "", inner)
+    # inner is: conn, args
+    sub(/^conn, /, "", inner)
+    args = inner
+
+    # Read the next non-blank line
+    triggered = 1
+    next
+  }
+
+  triggered == 1 {
+    # Skip blank lines, accumulating them
+    if ($0 ~ /^[[:space:]]*$/) {
+      blank_lines = blank_lines $0 "\n"
+      next
+    }
+
+    next_line = $0
+    triggered = 0
+
+    # Now look ahead: count how many subsequent lines (until scope boundary)
+    # reference "conn" — to decide Case 4 vs Cases 1-3
+    # We already have next_line. Check if next_line references conn.
+    # Then peek further lines.
+
+    # For simplicity: check if next_line matches Case 1, 2, or 3 patterns.
+    # If it does, check the line AFTER that for more conn references (Case 4 override).
+
+    # Case 1: var = helper(conn, status)
+    # helpers: html_response, json_response, text_response, response, redirected_to
+    case1 = 0
+    if (match(next_line, /^[[:space:]]*([a-z_]+) = (html_response|json_response|text_response|response|redirected_to)\(conn, [^)]+\)$/, m1)) {
+      case1 = 1
+      c1_var = m1[1]
+      c1_helper = m1[2]
+      # Extract status from helper(conn, status)
+      match(next_line, /\(conn, ([^)]+)\)/, m1s)
+      c1_status = m1s[1]
+    }
+
+    # Case 2: assert helper(conn, status) with optional =~ "..."
+    case2 = 0
+    if (match(next_line, /^[[:space:]]*assert (html_response|json_response|text_response|response|redirected_to)\(conn, ([^)]+)\)(.*)$/, m2)) {
+      case2 = 1
+      c2_helper = m2[1]
+      c2_status = m2[2]
+      c2_tail = m2[3]
+    }
+
+    # Case 3: assert %{...} = helper(conn, status)
+    case3 = 0
+    if (match(next_line, /^[[:space:]]*assert (%\{[^}]*\}) = (html_response|json_response|text_response|response|redirected_to)\(conn, ([^)]+)\)$/, m3)) {
+      case3 = 1
+      c3_pattern = m3[1]
+      c3_helper = m3[2]
+      c3_status = m3[3]
+    }
+
+    # If we matched Case 1, 2, or 3, emit the merged line
+    if (case1) {
+      print indent c1_var " = conn |> " verb "(" args ") |> " c1_helper "(" c1_status ")"
+      if (blank_lines != "") printf "%s", blank_lines
+      blank_lines = ""
+      next
+    }
+    if (case2) {
+      print indent "assert conn |> " verb "(" args ") |> " c2_helper "(" c2_status ")" c2_tail
+      if (blank_lines != "") printf "%s", blank_lines
+      blank_lines = ""
+      next
+    }
+    if (case3) {
+      print indent "assert " c3_pattern " = conn |> " verb "(" args ") |> " c3_helper "(" c3_status ")"
+      if (blank_lines != "") printf "%s", blank_lines
+      blank_lines = ""
+      next
+    }
+
+    # If next_line references conn at all, this is Case 4 territory
+    # (multiple uses without a recognized single-merge pattern)
+    if (next_line ~ /conn/) {
+      # Case 4: rename to response
+      print indent "response = conn |> " verb "(" args ")"
+      if (blank_lines != "") printf "%s", blank_lines
+      blank_lines = ""
+      # Replace conn with response in next_line
+      gsub(/conn/, "response", next_line)
+      print next_line
+      # Continue replacing conn->response in subsequent lines until scope boundary
+      renaming = 1
+      next
+    }
+
+    # No conn reference on next line — leave trigger unchanged (fallback)
+    print trigger_line
+    if (blank_lines != "") printf "%s", blank_lines
+    blank_lines = ""
+    print next_line
+    next
+  }
+
+  # Renaming mode for Case 4: replace conn with response until scope boundary
+  renaming == 1 {
+    # Scope boundary: blank line, "end", reduced indentation, or new conn = assignment
+    if ($0 ~ /^[[:space:]]*$/ || $0 ~ /^[[:space:]]*end$/ || $0 ~ /^[[:space:]]*conn =/) {
+      renaming = 0
+      print
+      next
+    }
+    gsub(/conn/, "response")
+    print
+    next
+  }
+
+  # Normal mode: pass through
+  {
+    if (blank_lines != "") {
+      printf "%s", blank_lines
+      blank_lines = ""
+    }
+    print
+  }
+
+  BEGIN { triggered = 0; renaming = 0; blank_lines = "" }
+  ' "$file" > "$tmpfile"
+
+  if $DRY_RUN; then
+    diff -u "$file" "$tmpfile" || true
+  else
+    mv "$tmpfile" "$file"
+    echo "Refactored: $file"
+  fi
+done