Report invalid global.json state in dotnet --info and hostfxr_resolve_sdk2

[elinor-fung]

We currently ignore invalid global.json, which can lead to unexpected/undesired behaviour. While we're not going to change that behaviour right now, this change adds some indication about this situation in dotnet --info and updates a hostfxr API to indicate if an invalid global.json was found.

• Make sdk_resolver track/store information about global.json even when it is deemed invalid
• Update dotnet --info to list invalid global.json file path and error message
• Add hostfxr_resolve_sdk2_result_key_t::global_json_state for hostfxr_resolve_sdk2 API
  • string values of: not_found, valid, invalid_json, invalid_data
  • This can be used in the SDK to add telemetry for when we have invalid global.json

Example part of dotnet --info:

global.json file:
  Invalid [C:\repos\helloworld\global.json]
    Version '9.0' is not valid for the 'sdk/version' value
    Invalid global.json is ignored for SDK resolution.

Before:

global.json file:
  Not found

cc @dotnet/appmodel @AaronRobinsonMSFT @richlander

Resolves #94496

Related:

• Add telemetry for invalid global.json when running a command sdk#50058
• dotnet.exe silently ignores global.json with a two-digit sdk version #96299
• Show error when using invalid global.json version string like 9.0.x sdk#49816

[Copilot]

Pull Request Overview

This PR enhances global.json error reporting in dotnet --info and the hostfxr_resolve_sdk2 API by tracking and exposing information about invalid global.json files instead of silently ignoring them.

• Tracks global.json state (not_found, valid, invalid_json, invalid_data) throughout the SDK resolution process
• Updates error reporting to provide specific error messages for JSON parsing and validation failures
• Adds new global_json_state result key to hostfxr_resolve_sdk2 API for telemetry purposes

Reviewed Changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/native/corehost/json_parser.h	Added get_error_message() method and m_parse_error field to store parsing errors
src/native/corehost/json_parser.cpp	Modified to store error messages instead of immediately tracing them
src/native/corehost/hostmisc/utils.h	Added format_string utility function for creating formatted strings
src/native/corehost/hostmisc/pal.h	Added template str_printf and strlen_printf functions for cross-platform string formatting
src/native/corehost/fxr/sdk_resolver.h	Restructured to track global.json state and error information in global_file_info struct
src/native/corehost/fxr/sdk_resolver.cpp	Refactored global.json parsing to return state information and detailed error messages
src/native/corehost/fxr/hostfxr.cpp	Added global_json_state result key and corresponding state strings for the API
src/native/corehost/fxr/command_line.cpp	Updated dotnet --info to display invalid global.json information with error details
src/native/corehost/runtime_config.cpp	Added error tracing using the new error message functionality
src/native/corehost/hostpolicy/deps_format.cpp	Added error tracing for dependency JSON parsing failures
src/native/corehost/comhost/clsidmap.cpp	Updated error messages to use the new error message functionality
Test files	Updated test expectations to match new error message formats and added tests for invalid global.json scenarios