[Luca-it15]

Summary

• refresh and carry the native Windows work from feat(system): native Windows ls/grep/wc/tree + PowerShell cmdlet rewrites #2547 onto the current develop branch
• add pure-Rust fallbacks for ls, tree, wc, and file-based grep/rg when Unix binaries are unavailable
• add powershell and pwsh wrappers plus safe, case-insensitive routing for Get-Content, Get-ChildItem, and Select-String (including aliases)
• preserve unsupported scripts, pipelines, interpolation, -File, and -EncodedCommand by passing them through unchanged
• support non-MSVC Windows linkers instead of always emitting the MSVC-only /STACK flag
• honor -v / --invert-match in the native search fallback so Select-String -NotMatch remains correct

Context and attribution

This branch deliberately preserves the original commits/authorship from @tienthegainz's #2547 and @sresam89's #2875, then adds the PowerShell/pwsh routing and current-develop integration work on top.

Addresses #1248.
Supersedes #2547.
Includes the fallback work from #2875.

Safety model

Only simple, statically tokenizable cmdlet invocations are routed through RTK. Compound PowerShell syntax and dynamic forms are left to the requested PowerShell executable, avoiding semantic changes to pipelines or scripts.

Validation

• cargo fmt --all --check
• cargo clippy --all-targets -- -D warnings
• 77 focused Windows/PowerShell tests passed (powershell, native ls, tree, wc, and search fallback)
• manual Windows smoke tests for powershell -Command, native listing/count/tree, and search with rg removed from PATH
• full local gnullvm run: 2505 passed; the remaining 30 failures are outside the modified modules and depend on Unix helper commands or sandboxed user-profile writes (the upstream base does not link with gnullvm before the linker fix in this PR)

GitHub's existing Windows MSVC job provides the authoritative full-suite check for this draft.

AI disclosure

The integration, tests, and PowerShell routing were developed with Codex assistance and manually validated on Windows.

[CLAassistant]

All committers have signed the CLA.

[KuSh]

Round 1 — CHANGES REQUESTED

Claim: rtk ls|tree|wc|grep|rg keep working on a host without the Unix tools through native Rust fallbacks, rtk powershell|pwsh plus bare-cmdlet rewrites route PowerShell file cmdlets through rtk, and the Windows build links with non-MSVC linkers.
Scope: accept if narrowed to "native ls/tree/wc/grep/rg fallbacks that fail loudly on anything they do not implement". Two parts leave the PR. The build.rs linker hunk is the one #3613 already carries (it also keys off the target, and #3613 is the open survivor of #3239), so it lands there. The PowerShell wrappers, cmdlet rewrites and their rules become a follow-up (#1248): they need a shell-aware rewrite, not a mapping table, and the evidence below is for that follow-up. Related open work: #2875 (its commits are carried here; it closes once this lands), #2355 and #2728 (same area); #4401 (flag grammars as data, which is what the fallbacks need to reject what they do not implement) and #4103 (child argument encoding) should land first.
Ran: merge of 3e97f69 onto develop 311ebcb (d5e72aa7c), debug binaries built from separate target dirs (md5 differ). Real tools: GNU ls/wc/tree/grep, ripgrep, PowerShell 7.4.2 (mcr.microsoft.com/powershell). Native paths run with an empty PATH and diffed against the real-tool path: ls 27 shapes, wc 25, tree 26, grep/rg 37 plus 11 confirmation rows; rewrite corpus of 40 commands on both binaries and through rtk hook claude; 14 cmdlet rows against real pwsh. Invariants: non-default targets (symlink, dangling link, dir with space, missing path), over-cap listing with the recall hint, stdin pipe for wc, under the hook, every decision of the new rewrite arm. Savings: ls 5987→775 B, tree 240→85 B against the 20% floor. Merged gate: fmt, clippy, cargo test --all (4091 unit tests) all exit 0; wincheck (windows-gnu) clean; CI 11/11 green on the PR head.
Pins: 143 mutations, 44 killed, 98 survived (11 of them equivalent or unreachable; 87 observable from the CLI).
Matrix: executed this round; pin check: executed this round
CI @3e97f6927: all green

Blocks merge (3, frozen)

1. src/cmds/system/{ls,wc_cmd,tree,search}.rs — native fallback answers where develop failed loudly (4 sites; all must change). Each fallback drops what it does not implement and prints a plausible result with exit 0 (or 1):
   • ls (ls.rs:309): entries ordered by the synthesized line, so by size text (a_one 1B, c_hundred, b_twenty, d_three); with the display cap the 0 B files show and Cargo.toml, README.md, big.txt fall behind it. -d, -t, -S, -r, --ignore= are ignored; -I zdir treats zdir as a path (exit 2); ls -- -dash.txt lists the cwd (exit 0).
   • wc (wc_cmd.rs:163): wc -L f prints 2L 3W 19B (real: 11), --bytes prints all three counts, --max-line-length is wrong, --total= ignored, wc -l -- -dash.txt reads stdin and prints 0.
   • tree (tree.rs:71): tree src docs prints only src; -I deep is consumed and not applied; -P '*.txt' src makes *.txt the root; tree nosuch exits 0 (real: exit 2, [error opening dir]); --level=1 and -L 0 are accepted.
   • search (search.rs:429, :603): -w, -F, -S, -A/-B/-C ignored (grep -w TOD matches TODO; grep -F . matches every line); BRE a\|b reaches Rust regex and matches nothing; non-UTF-8 and UTF-16 files are skipped silently; a missing path exits 1 with no message, or 0 beside a good path; .gitignore and hidden files are honoured under the grep engine, so grep -rn ignored . finds nothing where grep finds two lines.
   • dispatch (tree.rs:21): cfg!(windows) || !tool_exists("tree") sends every Windows user to the reduced walker, including those with a real tree on PATH (Git for Windows, scoop), who lose -P, -I, -s and the rest. On Linux and macOS the real binary is used whenever present. The native path should engage only when the tree on PATH is not the Unix one (or none exists), not on the platform alone.
     Evidence: transcripts for each row, native vs real tool. Test: a differential test per fallback over the forms it claims, and for every flag or operand it does not implement an assertion that stdout stays empty and exit is non-zero with a message. The corpus must show 0 differing rows on the supported forms.
2. src/discover/registry.rs:1707, powershell_cmd.rs:115 — PowerShell routing in the shared rewrite engine (cut by the narrowing; otherwise all must change). Regressions against develop:
   • type git → rtk read git (also echo hi && type git, FOO=1 type git), through rtk rewrite and rtk hook claude: bash's type exits 0 with the path, the rewritten form exits 1, or prints a file that happens to be named git. dir/dir src → rtk ls likewise. Copilot CLI hands its powershell tool to the same engine as Bash, so the engine cannot tell the shells apart.
   • /x/explicit/pwsh -File b.ps1 → rtk pwsh -File b.ps1 runs the pwsh found on PATH, not the binary named.
     Cmdlet mapping unfaithful against pwsh 7.4.2: Select-String -Pattern 'one|bar' matches lines 2 and 3, the rewrite is rtk grep -n -i 'one|bar' (BRE): exit 1, no output; -Pattern "-v" becomes the flag -v: exit 1, no output where PowerShell prints a -v b; single file prints 1:text without the path; no-match exits 1 where PowerShell exits 0; Get-ChildItem -Depth N → tree -L N is one level short (-Depth 1 . lists src/main.rs, tree -L 1 does not; the test pins the wrong mapping).
3. Unpinned behaviour (both areas). Native fallbacks: 45 of 66 mutations survive, including the four dispatch conditions (!tool_exists("ls"|"wc"|"tree"|engine.bin()) inverted: all tests pass), every exit-code mapping (ls.rs:410 2→1, :420 2→0, wc_cmd.rs:195 1→0), the walker options (git_ignore/git_global/git_exclude off), the default path, tree's multi-root and --all, wc's total line. PowerShell: 53 of 77 survive, including run_powershell never rewriting (main.rs:2166), the verbose and is_operational_command arms, the exit-code propagation of run() (→ 0), the redirect suffix, the Normal-context guard, the case-insensitivity and .exe of both rules, and the gc/type/dir/ls/gci aliases. The test the fix needs: for each, the input and the output that decides it (report: pin-A and pin-B tables); each mutation must turn it red. Held until the blockers above are settled, because the fix to 1 and 2 changes what the tests must assert.

Optional — will not hold merge; threads resolved by me

• src/cmds/system/README.md names native_grep (the code has fallback_capture), says -TotalCount→--max-lines (code: --head-lines) and omits the always-added -n.
• search.rs:421 cites #Windows-no-binary, which is not an issue.
• The fallback covers the grouped search form only: -l, -c, -o, --files, --help and the piped-stdin branch still fail with Failed to execute, which is loud and safe, but the PR text reads wider.
• Native ls -l prints 644/755 on Unix too, where PermissionsExt has the real mode.

Filed as follow-ups

• Shell-aware PowerShell routing (wrappers, cmdlet rewrites, rules with measured savings_pct instead of the inherited 60, categorize_command and RUST_HANDLED_COMMANDS entries, and ChildArgExt::child_args instead of .args(args) at powershell_cmd.rs:84 for the passthrough spawn): comment on #1248 with the rows above — outside the narrowed claim. Not filed yet.

Checked and correct — no need to re-verify

• Merge with develop is clean; fmt, clippy, tests and wincheck pass on the merge.
• tree src, -a, -L 2 and tree sizes equal the real tool after glyph normalisation; grep/rg -v, -i, -e, --max-count equal; wc default, -l -w -c -m -lw, several files and piped stdin equal; ls of a file, an empty dir and a dotfile equal.
• Get-Content -TotalCount N/-Tail N, Select-String -NotMatch equal pwsh on the same files; unsupported cmdlet options, pipes, $ and ; all pass through unchanged.
• The recall hint works on the native ls listing.
• build.rs target-env check type-checks for windows-gnu (wincheck); the hunk itself is #3613's.

Your questions

None.

Next

Narrow to the native fallbacks and the linker plumbing; make each fallback refuse what it does not implement (exit 2, message, empty stdout) and error on a missing target; move the PowerShell part to its own PR after #4401. Pin each fallback decision with a test that fails when mutated.
Threads: 0 open, 0 resolved this round.