Remove environment variable usage for TPA, app_path, and search_paths in browserhost (WASM)

[Copilot]

Plan: Remove environment variable usage for TPA, app_path, and search_paths in browserhost

• Update C++ BrowserHost_InitializeCoreCLR signature to accept TPA, app_path, and search_paths as UTF-8 arguments
• Update TypeScript wrapper in run.ts to pass these arguments from JS to C++
• Update libBrowserHost.footer.js to store values in config instead of ENV
• Pass the values directly from JS to the C++ function via ccall
• Ensure proper memory management for UTF-8 strings (Emscripten ccall handles this automatically)
• Remove getenv calls from browserhost.cpp
• Update comments to reflect new approach
• Build and test browser build (in CI)

Changes Summary

Modified Files

1. src/native/corehost/browserhost/browserhost.cpp

   • Changed BrowserHost_InitializeCoreCLR() to accept three const char* parameters
   • Removed pal::getenv() calls for TPA, app_path, and search_paths

2. src/native/corehost/browserhost/loader/run.ts

   • Retrieves TPA, app_path, and search_paths from config.environmentVariables
   • Passes them as arguments via ccall

3. src/native/corehost/browserhost/libBrowserHost.footer.js

   • Builds TPA, app_path, and search_paths during initialization
   • Stores them in config.environmentVariables (NOT in ENV)
   • Values are available when BrowserHost_InitializeCoreCLR is called

Key Design Decision

The values are stored in config.environmentVariables rather than ENV to maintain them in JavaScript scope while avoiding actual process environment pollution. They're then retrieved and passed as explicit arguments to the C++ function.

Benefits

1. No environment variable pollution (ENV)
2. Explicit argument passing to C++
3. Values prepared early when full assembly list is available
4. Memory managed automatically by Emscripten

Original prompt

Remove usage of environment variables for TPA, app_path, and search_paths in browserhost (WASM) build. Instead, pass these values as explicit UTF-8 encoded arguments from the JavaScript host/glue into the C++ browserhost.

Steps:

1. Identify all functions in src/native/corehost/browserhost/ that read TPA, app_path, or search_paths from environment variables (e.g., getenv), including main, runtime initialization, and helpers.
2. Change signatures of these functions to accept TPA, app_path, and search_paths as explicit UTF-8 encoded arguments.
   • Use const char* for single values.
   • Use const char* (delimited) or const char** with count for lists.
3. Update JavaScript/WASM glue to provide these arguments directly to the WASM entry point, and remove any code that sets these as env variables.
4. Remove all code that fetches these values via getenv or similar.
5. Ensure proper memory management:
   • Free any heap-allocated arguments (strdup/malloc) in C++ after use (typically after initialization).
   • If memory is owned by JS, document that JS must free it after the call.
6. Ensure all strings are UTF-8 encoded.
7. Build and test with ./build.sh clr+libs -rc release -os browser.
8. Update documentation and comments to reflect the new approach, and remove any unused env var code.

Checklist:

• All relevant functions accept TPA, app_path, and search_paths as UTF-8 arguments.
• JS/WASM glue updated to pass arguments directly.
• No environment variable usage for these in browserhost WASM code.
• Correct memory management and UTF-8 encoding.
• Documentation/comments updated.
• Browser (emscripten) build tested and verified.

This pull request was created as a result of the following prompt from Copilot chat.

Remove usage of environment variables for TPA, app_path, and search_paths in browserhost (WASM) build. Instead, pass these values as explicit UTF-8 encoded arguments from the JavaScript host/glue into the C++ browserhost.

Steps:

1. Identify all functions in src/native/corehost/browserhost/ that read TPA, app_path, or search_paths from environment variables (e.g., getenv), including main, runtime initialization, and helpers.
2. Change signatures of these functions to accept TPA, app_path, and search_paths as explicit UTF-8 encoded arguments.
   • Use const char* for single values.
   • Use const char* (delimited) or const char** with count for lists.
3. Update JavaScript/WASM glue to provide these arguments directly to the WASM entry point, and remove any code that sets these as env variables.
4. Remove all code that fetches these values via getenv or similar.
5. Ensure proper memory management:
   • Free any heap-allocated arguments (strdup/malloc) in C++ after use (typically after initialization).
   • If memory is owned by JS, document that JS must free it after the call.
6. Ensure all strings are UTF-8 encoded.
7. Build and test with ./build.sh clr+libs -rc release -os browser.
8. Update documentation and comments to reflect the new approach, and remove any unused env var code.

Checklist:

• All relevant functions accept TPA, app_path, and search_paths as UTF-8 arguments.
• JS/WASM glue updated to pass arguments directly.
• No environment variable usage for these in browserhost WASM code.
• Correct memory management and UTF-8 encoding.
• Documentation/comments updated.
• Browser (emscripten) build tested and verified.

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[pavelsavara]

@copilot build of runtime (Build browser-wasm linux Debug AllSubsets_CoreCLR) failed

[Copilot]

@copilot build of runtime (Build browser-wasm linux Debug AllSubsets_CoreCLR) failed

Fixed in commit f0e4c8f. The issue was that I was trying to build the TPA list in run.ts when not all assemblies were available yet. Now the values are prepared in libBrowserHost.footer.js during early initialization (where the complete assembly list exists) and stored in config.environmentVariables, then retrieved in run.ts to pass as arguments.