Replace Base.walkdir with variation that skips hidden directories

[nickrobinson251]

@charnik reported seeing long "scanning for test items" times, e.g.:

julia> @time runtests("test/Server/get-julia-replay-traces-tests.jl", name="get_julia_replay_traces: error case")
┌ Info: 2026-01-15T19:13:42.622
└ Scanning for test items in project `RAICode` at paths: test/Server/get-julia-replay-traces-tests.jl
┌ Info: 2026-01-15T19:13:47.886
└ Finished scanning for test items in 5.26 seconds. <-----

This comes from having large "hidden directories", including in this case .julia, at the root of the repo

Because ReTestItems.jl always searches down from the root of the repo looking for test files we were descending into hidden directories. This PR fixes that so we now skip hidden directories.

On that use-case, this PR reduces the scan time down from 5.26 to 0.21 seconds.

[nickrobinson251]

Verified this works on the original case (reported by @charnik)

And also had Claude write a benchmark script to show the impact:

$ cat walkdir_benchmark.jl
# Benchmark comparing _walkdir vs Base.walkdir performance
# when there are many files in hidden directories

using ReTestItems: _walkdir

const BENCH_DIR = joinpath(@__DIR__, "test_tree")

function setup_benchmark_tree(; num_hidden_dirs=10, num_subdirs_per_hidden=50, num_files_per_dir=100)
    # Clean up any existing benchmark directory
    rm(BENCH_DIR; force=true, recursive=true)
    mkpath(BENCH_DIR)

    # Create some normal directories with a few files
    for i in 1:5
        normal_dir = joinpath(BENCH_DIR, "normal_dir_$i")
        mkpath(normal_dir)
        for j in 1:10
            touch(joinpath(normal_dir, "file_$j.jl"))
        end
    end

    # Create hidden directories with LOTS of files and subdirectories
    for i in 1:num_hidden_dirs
        hidden_dir = joinpath(BENCH_DIR, ".hidden_dir_$i")
        mkpath(hidden_dir)

        for j in 1:num_subdirs_per_hidden
            subdir = joinpath(hidden_dir, "subdir_$j")
            mkpath(subdir)

            for k in 1:num_files_per_dir
                touch(joinpath(subdir, "file_$k.txt"))
            end
        end
    end

    # Count what we created
    total_hidden_files = num_hidden_dirs * num_subdirs_per_hidden * num_files_per_dir
    total_hidden_dirs = num_hidden_dirs * (1 + num_subdirs_per_hidden)  # parent + subdirs
    total_normal_files = 5 * 10
    total_normal_dirs = 5

    println("Created benchmark tree:")
    println("  Normal directories: $total_normal_dirs with $total_normal_files files")
    println("  Hidden directories: $total_hidden_dirs with $total_hidden_files files")
    println()
end

function count_walkdir_iterations(walkdir_func, root; collect_dirs=false)
    count = 0
    visited_dirs = String[]
    for (dir, dirs, files) in walkdir_func(root)
        count += 1
        if collect_dirs
            push!(visited_dirs, dir)
        end
    end
    return count, visited_dirs
end

function benchmark_walkdir(walkdir_func, root, name; warmup=true, show_dirs=false)
    # Warmup run
    if warmup
        count_walkdir_iterations(walkdir_func, root)
    end

    # Timed runs
    times = Float64[]
    iterations = 0
    visited_dirs = String[]
    for _ in 1:5
        t = @elapsed begin
            iterations, visited_dirs = count_walkdir_iterations(walkdir_func, root; collect_dirs=show_dirs)
        end
        push!(times, t)
    end

    avg_time = sum(times) / length(times)
    min_time = minimum(times)

    println("$name:")
    println("  Directories visited: $iterations")
    if show_dirs && !isempty(visited_dirs)
        println("  Directory names:")
        for dir in visited_dirs
            relpath_dir = relpath(dir, root)
            println("    - $relpath_dir")
        end
    end
    println("  Average time: $(round(avg_time * 1000, digits=3)) ms")
    println("  Minimum time: $(round(min_time * 1000, digits=3)) ms")
    println()

    return (iterations=iterations, avg_time=avg_time, min_time=min_time)
end

function run_benchmark()
    println("=" ^ 60)
    println("Benchmark: _walkdir vs Base.walkdir with hidden directories")
    println("=" ^ 60)
    println()

    # Setup
    setup_benchmark_tree(num_hidden_dirs=10, num_subdirs_per_hidden=50, num_files_per_dir=100)

    # Run benchmarks
    println("-" ^ 40)
    println("Results:")
    println("-" ^ 40)

    base_result = benchmark_walkdir(Base.walkdir, BENCH_DIR, "Base.walkdir")
    custom_result = benchmark_walkdir(_walkdir, BENCH_DIR, "_walkdir (skips hidden)"; show_dirs=true)

    # Summary
    println("=" ^ 60)
    println("Summary:")
    println("=" ^ 60)
    speedup = base_result.avg_time / custom_result.avg_time
    dirs_skipped = base_result.iterations - custom_result.iterations
    println("  Directories skipped by _walkdir: $dirs_skipped")
    println("  Speedup: $(round(speedup, digits=2))x faster")
    println()

    # Cleanup
    println("Cleaning up benchmark directory...")
    rm(BENCH_DIR; force=true, recursive=true)
    println("Done!")
end

# Run the benchmark
run_benchmark()

$ julia --project walkdir_benchmark.jl
============================================================
Benchmark: _walkdir vs Base.walkdir with hidden directories
============================================================

Created benchmark tree:
  Normal directories: 5 with 50 files
  Hidden directories: 510 with 50000 files

----------------------------------------
Results:
----------------------------------------
Base.walkdir:
  Directories visited: 516
  Average time: 197.247 ms
  Minimum time: 191.929 ms

_walkdir (skips hidden):
  Directories visited: 6
  Directory names:
    - .
    - normal_dir_1
    - normal_dir_2
    - normal_dir_3
    - normal_dir_4
    - normal_dir_5
  Average time: 0.781 ms
  Minimum time: 0.748 ms

============================================================
Summary:
============================================================
  Directories skipped by _walkdir: 510
  Speedup: 252.7x faster

Cleaning up benchmark directory...
Done!

[Copilot]

Pull request overview

This PR replaces Base.walkdir with a custom _walkdir function that automatically skips hidden directories (those starting with '.'), eliminating the need for manual filtering in the caller code.

Changes:

• Introduced _walkdir function that wraps Base.walkdir and filters out hidden directories before descending into them
• Replaced Base.walkdir call with _walkdir in include_testfiles!
• Removed redundant hidden_re regex and directory-level filtering since hidden directories are now excluded at traversal time

---

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 2 changed files in this pull request and generated 2 comments.

---

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[Drvi]

I think #225 would fix this in a way that I'd personally prefer, but this seems to work

[nickrobinson251]

I think #225 would fix this in a way that I'd personally prefer, but this seems to work

I think we could still do #225, right? What we spawn a task to do is kind of orthogonal to not descending into certain directories

[Drvi]

We could do it, but it would completely replace this PR since #225 also reimplements the walkdir function