“Exiting because upload-symbols was run in validation mode”消息有点误导，因为它也会在一切正常时出现。我用的是最新的Firebase Crashlytics 40.0，但它产生的输出与旧的Fabric脚本完全相同。
评论中

${PODS_ROOT}/FirebaseCrashlytics/run

好好解释一下：

# run
#
# This script is meant to be run as a Run Script in the "Build Phases" section
# of your Xcode project. It sends debug symbols to symbolicate stacktraces,
# sends build events to track versions, and onboards apps for Crashlytics.
#
# This script calls upload-symbols twice:
#
# 1) First it calls upload-symbols synchronously in "validation" mode. If the
#    script finds issues with the build environment, it will report errors to Xcode.
#    In validation mode it exits before doing any time consuming work.
#
# 2) Then it calls upload-symbols in the background to actually send the build
#    event and upload symbols. It does this in the background so that it doesn't
#    slow down your builds. If an error happens here, you won't see it in Xcode.
#
# You can find the output for the background execution in Console.app, by
# searching for "upload-symbols".
#
# If you want verbose output, you can pass the --debug flag to this script

提醒一下如果你想在www. example中看到这些信息 www.example.com ，先启动应用程序。..

我有这个问题，我解决了它，通过检查“运行脚本只有当安装”位于附近的编译

来自Fabric/Firebase支持的Chintan。你能检查一下在构建设置中，
带dSYM的变矮
文件已被选择为您的
调试信息格式
此外，从设备/模拟器中删除应用程序，清理项目，重新构建，运行并再次安装应用程序。联系support（at）fabric（dot）io如果这不起作用，您的应用可能需要手动激活。

正如@llude所提到的，为了将DYSM发送到FirebaseCrashlytics，您只需要在代码构建阶段脚本中添加一行：${PODS_ROOT}/FirebaseCrashlytics/run
如设置指南中所述： www.example.com
请注意，您需要添加2个字段作为input files（在构建阶段脚本中），以便update-symbols发送DYSM文件：

• plist文件路径
• dysm文件路径

//参见项目“granite”

错误：

Running upload-symbols in Build Phase mode
Validating build environment for Crashlytics...
Processing dSYMs...
Command PhaseScriptExecution failed with a nonzero exit code


2023-04-25 22:08:31.703 upload-symbols[23280:103455] Unable to get file attributes for dSYM file at path "/Users/abdallahandroid/Library/Developer/Xcode/DerivedData/Runner-gefdrreutulmdwdzwzzvbbjmuntb/Build/Intermediates.noindex/ArchiveIntermediates/Runner/BuildProductsPath/Release-iphoneos/App.framework.dSYM/Contents/Resources/DWARF"
2023-04-25 22:08:32.709 upload-symbols[23280:103455] Unable to get file attributes for dSYM file at path "/Users/abdallahandroid/Library/Developer/Xcode/DerivedData/Runner-gefdrreutulmdwdzwzzvbbjmuntb/Build/Intermediates.noindex/ArchiveIntermediates/Runner/BuildProductsPath/Release-iphoneos/App.framework.dSYM/Contents/Resources/DWARF"
Running upload-symbols in Build Phase mode
Validating build environment for Crashlytics...
Processing dSYMs...

修复：

1-更新项目依赖包
2-使您的flutter版本是最后更新稳定版本
3-更新你的mac和xcode到最新版本
4-flutter clean和pub get命令
5-首先删除旧pod：

pod deintegrate
pod cache clean --all

6-净Flutter

flutter clean
flutter pub get 
flutter pub upgrade

7-重新安装pod

pod install