fix: windows file tree

[TimBeyer]

What this PR does / why we need it:
Ensures that the GARDEN_GIT_SCAN_MODE=repo option works correctly on windows.
That's important because on windows, spawning subprocesses can be relatively slow (see https://gregoryszorc.com/blog/2021/04/06/surprisingly-slow/) and by default we call git many times, which adds up for large projects and can really slow things down.
Previously it was broken because of assumptions around how the file system is rooted, which didn't hold under windows.
Now comes with a small test to verify the behavior.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[TimBeyer]

Closing for now as on windows I would still end up with 0 files loaded when using this scan mode.

[TimBeyer]

i garden               → Running in Garden environment dev.default
[silly] Scanning for configs (force=false)
[silly] Scanning for configs in C:\Users\timbe\Code\garden-large-repo-generator
[silly] TreeCache: No cached value for key ["git-repo-files","C:\\Users\\timbe\\Code\\garden-large-repo-generator"]
[silly] TreeCache: No cached value for key ["git-repo-files","C:\\Users\\timbe\\Code\\garden-large-repo-generator"]
Scanning repository at C:\Users\timbe\Code\garden-large-repo-generator
i git [debug]          → Scanning project root at C:\Users\timbe\Code\garden-large-repo-generator
  → Includes: (none)
  → Excludes: **/.garden/**/*
i git [silly]          → Calling git with args 'diff-index --name-only HEAD C:\Users\timbe\Code\garden-large-repo-generator' in C:\Users\timbe\Code\garden-large-repo-generator
i git [silly]          → Calling git with args '--glob-pathspecs ls-files --ignored --cached --exclude C:\Users\timbe\Code\garden-large-repo-generator\.garden --exclude **/.garden/**/* --exclude-per-directory .gardenignore' in C:\Users\timbe\Code\garden-large-repo-generator
i git [silly]          → Calling git with args '--glob-pathspecs ls-files -s --others --cached --exclude C:\Users\timbe\Code\garden-large-repo-generator\.garden --exclude **/.garden/**/* --exclude-per-directory .gardenignore' in C:\Users\timbe\Code\garden-large-repo-generator
i git [debug]          → Found 4430 files in project root C:\Users\timbe\Code\garden-large-repo-generator
[silly] TreeCache: Setting value for key ["git-repo-files","C:\\Users\\timbe\\Code\\garden-large-repo-generator"]
[debug] Found 4430 files in module path, filtering by 1 include and 6 exclude globs
[silly] Include globs: C:\Users\timbe\Code\garden-large-repo-generator\**\*garden.y*ml
[silly] Exclude globs: C:\Users\timbe\Code\garden-large-repo-generator\.garden\**\*, C:\Users\timbe\Code\garden-large-repo-generator\.git\**\*, C:\Users\timbe\Code\garden-large-repo-generator\.gitmodules, C:\Users\timbe\Code\garden-large-repo-generator\.garden\**\*, C:\Users\timbe\Code\garden-large-repo-generator\debug-info*\**, C:\Users\timbe\Code\garden-large-repo-generator\.garden\**\*
[debug] Found 0 files in module path after glob matching
[debug] Scanned and found 0 actions, 0 workflows and 0 modules

[TimBeyer]

Comparing that with (hopefully) the same sort of setup on MacOS

ℹ garden               → Running in Garden environment dev.default
[silly] Scanning for configs (force=false)
[silly] Scanning for configs in /Users/tim/Development/garden/garden-large-repo-generator
[silly] TreeCache: No cached value for key ["git-repo-files","/Users/tim/Development/garden/garden-large-repo-generator"]
[silly] TreeCache: No cached value for key ["git-repo-files","/Users/tim/Development/garden/garden-large-repo-generator"]
Scanning repository at /Users/tim/Development/garden/garden-large-repo-generator
ℹ git [debug]          → Scanning project root at /Users/tim/Development/garden/garden-large-repo-generator
  → Includes: (none)
  → Excludes: **/.garden/**/*
ℹ git [silly]          → Calling git with args 'diff-index --name-only HEAD /Users/tim/Development/garden/garden-large-repo-generator' in /Users/tim/Development/garden/garden-large-repo-generator
ℹ git [silly]          → Calling git with args '--glob-pathspecs ls-files --ignored --cached --exclude /Users/tim/Development/garden/garden-large-repo-generator/.garden --exclude **/.garden/**/* --exclude-per-directory .gardenignore' in /Users/tim/Development/garden/garden-large-repo-generator
ℹ git [silly]          → Calling git with args '--glob-pathspecs ls-files -s --others --cached --exclude /Users/tim/Development/garden/garden-large-repo-generator/.garden --exclude **/.garden/**/* --exclude-per-directory .gardenignore' in /Users/tim/Development/garden/garden-large-repo-generator
ℹ git [debug]          → Found 5532 files in project root /Users/tim/Development/garden/garden-large-repo-generator
[silly] TreeCache: Setting value for key ["git-repo-files","/Users/tim/Development/garden/garden-large-repo-generator"]
[debug] Found 5532 files in module path, filtering by 1 include and 6 exclude globs
[silly] Include globs: /Users/tim/Development/garden/garden-large-repo-generator/**/*garden.y*ml
[silly] Exclude globs: /Users/tim/Development/garden/garden-large-repo-generator/.garden/**/*, /Users/tim/Development/garden/garden-large-repo-generator/.git/**/*, /Users/tim/Development/garden/garden-large-repo-generator/.gitmodules, /Users/tim/Development/garden/garden-large-repo-generator/.garden/**/*, /Users/tim/Development/garden/garden-large-repo-generator/debug-info*/**, /Users/tim/Development/garden/garden-large-repo-generator/.garden/**/*
[debug] Found 253 files in module path after glob matching

[TimBeyer]

The issue lies here: https://github.com/micromatch/micromatch#backslashes

We join the path of the directory together with the glob to do the matching:

C:\Users\timbe\Code\garden-large-repo-generator\**\*garden.y*ml

This makes it so that the glob gets escaped and things break on windows.
We need to remove the root path from everything to match and then use globs to not match the preceding path.

[TimBeyer]

Tested on windows and found performance to be signficantly improved with this enabled.
We still need to check on other git calls that we do subsequently which also impact performance pretty negatively, but overall this is an almost 2x improvement.

Just need to look at fixing the tests in framework that relate to the glob fixes I had to do.

[stefreak]

Aaaah, this is awesome! 👏

[stefreak]

Looks good to me