ci(ios): extract shared, grep-verified Podfile dep-resolution patch script

The "Configure Dependency Resolution Mode" step was duplicated verbatim
across the ios and ios-release-archive jobs in tests_e2e_ios.yml, and its
plain sed patches silently no-op on a Podfile wording change instead of
failing loudly. Extract both real patches (linkage swap,
$RNFirebaseDisableSPM prepend) into
.github/workflows/scripts/configure-ios-dep-resolution.sh, with a grep
assertion after each patch, and drop the third sed line
(/SWIFT_ENABLE_EXPLICIT_MODULES/d) entirely -- that setting moved into
firebase_spm.rb's Ruby post_install hook and is dead code in the Podfile
today.

Author: russellwheatley

.github/workflows/scripts/configure-ios-dep-resolution.sh

@@ -0,0 +1,65 @@
+#!/bin/bash
+# Configure tests/ios/Podfile for the CI dependency-resolution matrix leg (spm vs cocoapods).
+# Shared by both "Configure Dependency Resolution Mode" steps in tests_e2e_ios.yml
+# (the `ios` job and the `ios-release-archive` job) so the two legs can't drift apart.
+#
+# Usage: configure-ios-dep-resolution.sh <spm|cocoapods> [podfile-dir]
+#   podfile-dir defaults to tests/ios, since every caller in tests_e2e_ios.yml runs
+#   with the workflow's default working directory (the repo root).
+#
+# spm mode is a no-op: the checked-in Podfile already resolves Firebase via SPM
+# (dynamic linkage, no $RNFirebaseDisableSPM flag -- see packages/app/firebase_spm.rb).
+#
+# cocoapods mode patches the Podfile to force static linkage and disable SPM
+# resolution. Each patch is grep-verified immediately after being applied, so a future
+# change to the Podfile's wording (e.g. reformatting `linkage = 'dynamic'`) fails this
+# script loudly instead of silently leaving the "cocoapods" CI leg testing the SPM path
+# a second time.
+set -euo pipefail
+
+log_dep_resolution() {
+  echo "[dep-resolution] $*"
+}
+
+configure_cocoapods_mode() {
+  local podfile_dir="$1"
+  local podfile="${podfile_dir}/Podfile"
+
+  log_dep_resolution "configuring CocoaPods-only mode (disabling SPM) in ${podfile}"
+
+  sed -i '' "s/^linkage = 'dynamic'/linkage = 'static'/" "$podfile"
+  grep -q "^linkage = 'static'" "$podfile" || {
+    log_dep_resolution "ERROR: expected \"linkage = 'static'\" in ${podfile} after sed, but it was not found -- has the Podfile's linkage line wording changed?"
+    exit 1
+  }
+
+  printf '%s\n' '$RNFirebaseDisableSPM = true' | cat - "$podfile" > "${podfile}.tmp" && mv "${podfile}.tmp" "$podfile"
+  local first_line
+  first_line="$(head -n 1 "$podfile")"
+  [[ "$first_line" == '$RNFirebaseDisableSPM = true' ]] || {
+    log_dep_resolution "ERROR: expected the first line of ${podfile} to be '\$RNFirebaseDisableSPM = true' after prepend, got: ${first_line}"
+    exit 1
+  }
+
+  log_dep_resolution "Podfile configured for CocoaPods-only mode"
+}
+
+configure_spm_mode() {
+  log_dep_resolution "using default SPM mode (dynamic linkage)"
+}
+
+MODE="${1:-}"
+PODFILE_DIR="${2:-tests/ios}"
+
+case "$MODE" in
+  cocoapods)
+    configure_cocoapods_mode "$PODFILE_DIR"
+    ;;
+  spm)
+    configure_spm_mode
+    ;;
+  *)
+    log_dep_resolution "ERROR: unrecognized dependency-resolution mode '${MODE}' (expected 'spm' or 'cocoapods')"
+    exit 1
+    ;;
+esac

.github/workflows/tests_e2e_ios.yml

@@ -263,17 +263,7 @@ jobs:
           restore-keys: ${{ runner.os }}-${{ matrix.dep-resolution }}-ios-pods-v3
 
       - name: Configure Dependency Resolution Mode
-        run: |
-          if [[ "${{ matrix.dep-resolution }}" == "cocoapods" ]]; then
-            echo "Configuring CocoaPods-only mode (disabling SPM)"
-            cd tests/ios
-            sed -i '' "s/^linkage = 'dynamic'/linkage = 'static'/" Podfile
-            printf '%s\n' '$RNFirebaseDisableSPM = true' | cat - Podfile > Podfile.tmp && mv Podfile.tmp Podfile
-            sed -i '' "/SWIFT_ENABLE_EXPLICIT_MODULES/d" Podfile
-            echo "Podfile configured for CocoaPods-only mode"
-          else
-            echo "Using default SPM mode (dynamic linkage)"
-          fi
+        run: .github/workflows/scripts/configure-ios-dep-resolution.sh "${{ matrix.dep-resolution }}"
 
       - name: Pod Install
         # https://github.com/nick-fields/retry/releases
@@ -663,17 +653,7 @@ jobs:
           restore-keys: ${{ runner.os }}-${{ matrix.dep-resolution }}-ios-pods-v3
 
       - name: Configure Dependency Resolution Mode
-        run: |
-          if [[ "${{ matrix.dep-resolution }}" == "cocoapods" ]]; then
-            echo "Configuring CocoaPods-only mode (disabling SPM)"
-            cd tests/ios
-            sed -i '' "s/^linkage = 'dynamic'/linkage = 'static'/" Podfile
-            printf '%s\n' '$RNFirebaseDisableSPM = true' | cat - Podfile > Podfile.tmp && mv Podfile.tmp Podfile
-            sed -i '' "/SWIFT_ENABLE_EXPLICIT_MODULES/d" Podfile
-            echo "Podfile configured for CocoaPods-only mode"
-          else
-            echo "Using default SPM mode (dynamic linkage)"
-          fi
+        run: .github/workflows/scripts/configure-ios-dep-resolution.sh "${{ matrix.dep-resolution }}"
 
       - name: Pod Install
         uses: nick-fields/retry@ad984534de44a9489a53aefd81eb77f87c70dc60 # v4.0.0