Performace problem when many ignored files are present in the repo

[prusse-martin]

Related to #58

Listing all ignored files to later filter out those can have a big impact when we have some ignored folder with many files.
Maybe we should call ls-tree to obtain the file list:

W:\alfasim\Projects\alfasim\alfasim_gui (fb-ASIM-3738-transient-input -> origin/current)
(_alfasim_gui-win64-py36) λ git ls-tree -r HEAD --name-only | head -n 15
.coveragerc
.project
.pydevproject
.vscode/launch.json
.vscode/settings.json
.vscode/tasks.json
alfasim_gui.spec.yml
dist/all/.gitignore
docs/.gitignore
docs/ALFAsim_Technical_Manual___EN_US.pdf
docs/conf.py
docs/gui.rst
docs/images/advanced.png
docs/images/advanced_options.png
docs/images/advanced_options_model_explorer.png

In my local machine:

W:\alfasim\Projects\alfasim\alfasim_gui (fb-ASIM-3738-transient-input -> origin/current)
(_alfasim_gui-win64-py36) λ git status --ignored --untracked-files=all  --porcelain=2 | wc -l
41613

W:\alfasim\Projects\alfasim\alfasim_gui (fb-ASIM-3738-transient-input -> origin/current)
(_alfasim_gui-win64-py36) λ git ls-tree -r HEAD --name-only | wc -l
858

Having git list all untracked files (41k) to later filter the files from the repo was a bad idea (my bad).

Does calling git ls-tree -r HEAD --name-only to get the name of the tracked files plus parsing the output of git status --untracked-files=all to get the untracked files letting git it self filter out the ignored files a good approach?

[nicoddemus]

Having git list all untracked files (41k) to later filter the files from the repo was a bad idea (my bad).

Can you post some timings as well? I wouldn't think listing 41k files would take too long (we're talking minutes if I recall our discussion in RC).

Does calling git ls-tree -r HEAD --name-only to get the name of the tracked files plus parsing the output of git status --untracked-files=all to get the untracked files letting git it self filter out the ignored files a good approach?

Not sure, why would that be faster? I mean currently we do a single git call (#59), you think is the parsing of that output that is showing a slowdown?

[prusse-martin]

@ggrbill was having a 20min delay when executing that one single call ( git status --ignored --untracked-files=all --porcelain=2), his ignored "tmp" folder had over 2GB and the file count was well over 4 000 000 000.
Asking git to list will allow it to better handle the "ignored" files.

[nicoddemus]

ahh ok, got it, thanks.

So the proposal is to only execute ff on tracked files except untracked files, instead of executing on all files except ignored ones?

[prusse-martin]

(tracked files) + (untracked but not ignored)