Robust ASC key normalization with diagnostics for TestFlight deploy

Replace fragile BEGIN/base64 branch with multi-strategy key parser
that handles raw PEM, escaped newlines, base64-encoded PEM, mangled
line wrapping, CR/LF issues, and double-encoding. Validates key with
OpenSSL::PKey.read before passing to Fastlane via key_filepath (temp
file) instead of key_content to bypass Fastlane's own parsing. Prints
safe diagnostics (no key material) if all strategies fail.

mobile/fastlane/Fastfile

@@ -1,8 +1,9 @@
 require 'openssl'
+require 'base64'
+require 'tempfile'
 
-# Fastlane 2.234.0 uses OpenSSL::PKey::EC.new which rejects PKCS#8 keys on
-# OpenSSL 3.x ("invalid curve name"). Prepend a wrapper that falls back to
-# OpenSSL::PKey.read, which handles both PKCS#8 and SEC1 formats.
+# OpenSSL 3.x rejects PKCS#8 keys via EC.new ("invalid curve name").
+# Prepend a wrapper that falls back to PKey.read for both formats.
 module OpenSSLECNewFix
   def new(arg = nil, *rest)
     super
@@ -13,6 +14,73 @@ module OpenSSLECNewFix
 end
 OpenSSL::PKey::EC.singleton_class.prepend(OpenSSLECNewFix)
 
+def normalize_p8_key(raw)
+  candidates = []
+
+  cleaned = raw.gsub("\r", "")
+  with_newlines = cleaned.gsub('\n', "\n")
+  candidates << ["raw (newlines normalized)", with_newlines]
+
+  if with_newlines.include?("BEGIN")
+    b64_body = with_newlines.gsub(/-----(?:BEGIN|END)[^-]+-----/, '').gsub(/\s+/, '')
+    rewrapped = "-----BEGIN PRIVATE KEY-----\n#{b64_body.scan(/.{1,64}/).join("\n")}\n-----END PRIVATE KEY-----\n"
+    candidates << ["rewrapped PEM", rewrapped]
+  end
+
+  begin
+    decoded = Base64.decode64(cleaned.strip)
+    if decoded.include?("BEGIN")
+      decoded_clean = decoded.gsub("\r", "").gsub('\n', "\n")
+      candidates << ["base64→PEM", decoded_clean]
+      b64_body = decoded_clean.gsub(/-----(?:BEGIN|END)[^-]+-----/, '').gsub(/\s+/, '')
+      rewrapped = "-----BEGIN PRIVATE KEY-----\n#{b64_body.scan(/.{1,64}/).join("\n")}\n-----END PRIVATE KEY-----\n"
+      candidates << ["base64→PEM rewrapped", rewrapped]
+    elsif decoded.length.between?(32, 256)
+      candidates << ["base64→DER", decoded]
+    end
+  rescue StandardError
+    # not valid base64
+  end
+
+  begin
+    double = Base64.decode64(Base64.decode64(cleaned.strip).strip)
+    if double.include?("BEGIN")
+      candidates << ["double-base64→PEM", double.gsub("\r", "")]
+    end
+  rescue StandardError
+    # not double-encoded
+  end
+
+  candidates.each do |name, content|
+    begin
+      OpenSSL::PKey.read(content)
+      UI.success("ASC key parsed with strategy: #{name}")
+      return content
+    rescue StandardError => e
+      UI.message("Strategy '#{name}' failed: #{e.class} — #{e.message}")
+    end
+  end
+
+  UI.error("=== ASC KEY DIAGNOSTIC (no key material shown) ===")
+  UI.error("Raw byte length: #{raw.bytesize}")
+  UI.error("Starts with BEGIN: #{raw.strip.start_with?('-----BEGIN')}")
+  UI.error("Ends with -----: #{raw.strip.end_with?('-----')}")
+  UI.error("Has real newlines: #{raw.include?("\n")}")
+  UI.error("Has literal backslash-n: #{raw.include?('\\n')}")
+  UI.error("Has carriage returns: #{raw.include?("\r")}")
+  UI.error("Printable ASCII ratio: #{(raw.count(' -~').to_f / raw.bytesize * 100).round(1)}%")
+  UI.error("Header (first 27 chars): #{raw[0..26]}")
+  begin
+    d = Base64.decode64(raw.strip)
+    UI.error("After base64 decode — length: #{d.bytesize}, header: #{d[0..26]}")
+  rescue StandardError
+    UI.error("base64 decode raised an exception")
+  end
+  UI.error("=== END DIAGNOSTIC ===")
+
+  raise "Could not parse ASC_KEY_CONTENT in any known format. See diagnostics above."
+end
+
 default_platform(:ios)
 
 platform :ios do
@@ -20,22 +88,19 @@ platform :ios do
   lane :beta do
     setup_ci
 
-    raw = ENV["ASC_KEY_CONTENT"]
-    if raw.include?("BEGIN")
-      key_content = raw.gsub('\n', "\n")
-      is_base64 = false
-    else
-      key_content = raw
-      is_base64 = true
-    end
+    key_pem = normalize_p8_key(ENV["ASC_KEY_CONTENT"])
+
+    key_path = File.join(Dir.tmpdir, "asc_api_key.p8")
+    File.write(key_path, key_pem)
 
     app_store_connect_api_key(
       key_id: ENV["ASC_KEY_ID"],
       issuer_id: ENV["ASC_ISSUER_ID"],
-      key_content: key_content,
-      is_key_content_base64: is_base64
+      key_filepath: key_path
     )
 
+    File.delete(key_path) if File.exist?(key_path)
+
     match(type: "appstore", readonly: true)
 
     increment_build_number(