[release/5.0] Add option to RazorPageGenerator for #line preprocessor directives (#27765)

[dougbu]

• cherry-picked from 1a241fc in 'master' branch

• avoid new CS1504 errors because compiler can't find the ErrorPage.cshtml file

  • we override Arcade's $(MicrosoftCodeAnalysisCSharpVersion)

• use new option in GeneratePage.ps1 script

  • script also did not know RazorSyntaxGenerator had moved to this repo

• reflect latest RazorSyntaxGenerator processing

  • run GeneratePage.ps1
  • update README.md

nits:

• quote all paths in GeneratePage.ps1 script
• remove passive voice in README.md

[dougbu]

Suggesting tell-mode for 5.0.3. Sound right @Pilchie❔

[Pilchie]

Why tell mode? Can you elaborate on what your fixing, where it's used, etc? I'm not familiar with this bit of the repo.

[dougbu]

Why tell mode?

Short answer

It's all build infrastructure. Well, not quite but…

More correct answer

The main changes are in a tool (RazorSyntaxGenerator) that does not ship and is only used manually. I am changing a single generated source file but only its contained #line pragmas and only to satisfy Roslyn.

Background

The change corrects build failures I've repeatedly seen locally but aren't yet happening on the CI.

The src/Shared/ErrorPage/ErrorPage.Designer.cs file is checked into the repo and compiled into a number of our projects. Newer versions of Roslyn validate the generated #line pragmas in this file and complain when the ErrorPage.cshtml file isn't found because it's in the src/Shared/ErrorPage/Views sub-directory. That is, builds fail because the #line pragmas are wrong.

We fixed this in 'master' but haven't done the same in 'release/5.0' yet. This will soon be necessary because the Roslyn compiler ships (in part) with VS and core-eng updates VS on the build agents.

The specific fix is to correct the tool used to generate the ErrorPage.Designer.cs file (RazorSyntaxGenerator) and then use it to fix the #line pragmas.

An alternate fix would be to move the generated file into the Views sub-directory and then change the references in consuming projects. I chose the current fix because it was somewhat more localized and gave me an opportunity to fix the "script also did not know RazorSyntaxGenerator had moved to this repo" bit.

[Pilchie]

This will soon be necessary because the Roslyn compiler ships (in part) with VS and core-eng updates VS on the build agents.

But we build these bits with dotnet build right? So they should be isolated from the VS version?

[dougbu]

But we build these bits with dotnet build right? So they should be isolated from the VS version?

Yup but with emphasis on the word "should".

My deeper suspicion is this problem will primarily impact local builds of the 'release/5.0' branch after switching from 'master' (or branches based on either). That comes from dotnet build-server shutdown clearing the problem. Seems likely the problem is just that builds in 'release/5.0' end up using the newer Roslyn bits configured in 'master' because they're held in the VB/C# compiler server.

Note our build.ps1 and build.sh scripts disable node reuse. Unfortunately that affects dotnet msbuild processes, not the server process(es) used.

We enable the compiler server pretty much everywhere (in eng/Workarounds.props). That's identified as a workaround for dotnet/roslyn#27975 though it's probably more about the 5X performance degradation when not using the compiler server.

[Pilchie]

Got it, thanks for working through the details with me. I'm okay with Tell-Mode for this now.

[dougbu]

/backport to release/3.1

[github-actions]

Started backporting to release/3.1: https://github.com/dotnet/aspnetcore/actions/runs/924024165

[github-actions]

@dougbu backporting to release/3.1 failed, the patch most likely resulted in conflicts:

$ git am --3way --ignore-whitespace --keep-non-patch changes.patch

Applying: [release/5.0] Add option to `RazorPageGenerator` for `#line` preprocessor directives (#27765) - cherry-picked from 1a241fcfc2f8 in 'master' branch
Using index info to reconstruct a base tree...
A	src/Middleware/tools/RazorPageGenerator/Program.cs
M	src/Shared/ErrorPage/GeneratePage.ps1
M	src/Shared/ErrorPage/README.md
Falling back to patching base and 3-way merge...
Auto-merging src/Shared/ErrorPage/README.md
CONFLICT (content): Merge conflict in src/Shared/ErrorPage/README.md
Auto-merging src/Shared/ErrorPage/GeneratePage.ps1
CONFLICT (content): Merge conflict in src/Shared/ErrorPage/GeneratePage.ps1
CONFLICT (modify/delete): src/Middleware/tools/RazorPageGenerator/Program.cs deleted in HEAD and modified in [release/5.0] Add option to `RazorPageGenerator` for `#line` preprocessor directives (#27765) - cherry-picked from 1a241fcfc2f8 in 'master' branch. Version [release/5.0] Add option to `RazorPageGenerator` for `#line` preprocessor directives (#27765) - cherry-picked from 1a241fcfc2f8 in 'master' branch of src/Middleware/tools/RazorPageGenerator/Program.cs left in tree.
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 [release/5.0] Add option to `RazorPageGenerator` for `#line` preprocessor directives (#27765) - cherry-picked from 1a241fcfc2f8 in 'master' branch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!