Fix Windows long paths with UAC repair and visible fallback warnings

.github/workflows/check-windows.yml

@@ -167,3 +167,75 @@ jobs:
             throw "Warm check did not reuse the verified source launcher"
           }
           # The hosted runner discards RUNNER_TEMP after the job.
+
+      - name: Windows long-path repair and fallback smoke
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = 'Stop'
+          $registry = 'HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem'
+          $original = Get-ItemPropertyValue -Path $registry -Name LongPathsEnabled -ErrorAction SilentlyContinue
+          $buildOutput = @(& soldr cargo build -p fbuild-cli -p fbuild-daemon --bins --message-format=json)
+          if ($LASTEXITCODE -ne 0) {
+            $buildOutput | Write-Output
+            throw 'could not build the Windows smoke binaries'
+          }
+          $binPaths = @{}
+          foreach ($line in $buildOutput) {
+            if (-not $line.StartsWith('{')) { continue }
+            $artifact = $line | ConvertFrom-Json
+            if ($artifact.reason -eq 'compiler-artifact' -and ($artifact.target.kind -contains 'bin') -and $artifact.executable) {
+              $binPaths[$artifact.target.name] = $artifact.executable
+            }
+          }
+          foreach ($name in @('fbuild', 'fbuild-daemon')) {
+            if (-not $binPaths.ContainsKey($name) -or -not (Test-Path -LiteralPath $binPaths[$name] -PathType Leaf)) {
+              throw "missing Windows smoke executable: $name"
+            }
+          }
+          $cli = $binPaths['fbuild']
+          $daemon = $binPaths['fbuild-daemon']
+          foreach ($binary in @($cli, $daemon)) {
+            $image = [Text.Encoding]::UTF8.GetString([IO.File]::ReadAllBytes($binary))
+            if ($image -notmatch 'longPathAware[^>]*>true</' -or $image -notmatch 'level="asInvoker"') {
+              throw "Missing Windows manifest in $binary"
+            }
+          }
+          try {
+            # This disposable hosted runner is already elevated. Exercise the
+            # fixed helper without requiring an interactive UAC desktop.
+            New-ItemProperty -Path $registry -Name LongPathsEnabled -PropertyType DWord -Value 0 -Force | Out-Null
+            & $cli --__fix-win-helper
+            if ($LASTEXITCODE -ne 0) { throw 'long-path helper failed' }
+            if ((Get-ItemPropertyValue -Path $registry -Name LongPathsEnabled) -ne 1) {
+              throw 'long-path helper did not verify its change'
+            }
+            & $cli --fix-win --no-update-check
+            if ($LASTEXITCODE -ne 0) { throw 'already-enabled repair failed' }
+            $env:FBUILD_DEV_MODE = '0'
+            $env:RUNNING_PROCESS_DISABLE = '1'
+            & $cli --no-update-check build tests/platform/uno --dry-run
+            if ($LASTEXITCODE -ne 0) { throw 'enabled daemon startup failed' }
+            $before = Get-Content (Join-Path $env:USERPROFILE '.fbuild\prod\daemon\root-owner.json') -Raw | ConvertFrom-Json
+            New-ItemProperty -Path $registry -Name LongPathsEnabled -PropertyType DWord -Value 0 -Force | Out-Null
+            $env:CI = 'true'
+            $output = & $cli --no-update-check install tests/platform/esp32dev --dry-run --json 2> long-path-warning.txt
+            $code = $LASTEXITCODE
+            if ($code -ne 0) { throw "fallback package preview failed: $code" }
+            $output | ConvertFrom-Json | Out-Null
+            $warning = Get-Content long-path-warning.txt -Raw
+            if ($warning -notmatch 'WARNING:' -or $warning -notmatch 'fix-win' -or $warning.Contains([char]27)) {
+              throw 'fallback warning is missing or contains ANSI in redirected stderr'
+            }
+            & $cli --no-update-check build tests/platform/uno --dry-run
+            if ($LASTEXITCODE -ne 0) { throw 'disabled-policy daemon handoff failed' }
+            $after = Get-Content (Join-Path $env:USERPROFILE '.fbuild\prod\daemon\root-owner.json') -Raw | ConvertFrom-Json
+            if ($before.pid -eq $after.pid) { throw 'daemon was reused after the registry changed' }
+            & $cli --no-update-check daemon stop
+            if ($LASTEXITCODE -ne 0) { throw 'smoke daemon did not stop' }
+          } finally {
+            if ($null -eq $original) {
+              Remove-ItemProperty -Path $registry -Name LongPathsEnabled -ErrorAction SilentlyContinue
+            } else {
+              New-ItemProperty -Path $registry -Name LongPathsEnabled -PropertyType DWord -Value $original -Force | Out-Null
+            }
+          }

README.md

@@ -153,6 +153,10 @@ pip install fbuild
 For source installs, platform notes, and first-run cache behavior, start with
 the [getting started guide](docs/getting-started/README.md).
 
+On Windows, `fbuild --fix-win` enables long paths with administrator approval.
+Interactive ESP32 commands offer this repair when needed; declining uses a
+short cache and prints a yellow warning. See [Windows setup](docs/getting-started/README.md#windows-long-paths).
+
 ## Command Quick Start
 
 fbuild reads the same `platformio.ini` files as PlatformIO. Use these commands

ci/platform_boundary_research.tsv

@@ -10,13 +10,17 @@ crates/fbuild-core/src/platform/linux/device.rs	33	native_path	std::os::unix::fs
 crates/fbuild-core/src/platform/linux/device.rs	41	native_path	libc::	process	host_mechanic
 crates/fbuild-core/src/platform/linux/device.rs	41	native_path	libc::	process	host_mechanic
 crates/fbuild-core/src/platform/linux/fs.rs	2	native_path	std::os::unix::fs::PermissionsExt	fs	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	13	native_path	std::os::unix::fs::MetadataExt	fs	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	57	native_path	std::os::unix::fs::symlink	fs	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	61	native_path	std::os::unix::fs::symlink	fs	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	105	native_path	std::os::unix::ffi::OsStrExt	process	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	110	native_path	libc::	process	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	112	native_path	libc::	process	host_mechanic
-crates/fbuild-core/src/platform/linux/fs.rs	122	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	31	native_path	std::os::unix::fs	fs	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	51	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	51	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	54	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	68	native_path	std::os::unix::fs::MetadataExt	fs	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	112	native_path	std::os::unix::fs::symlink	fs	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	116	native_path	std::os::unix::fs::symlink	fs	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	158	native_path	std::os::unix::ffi::OsStrExt	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	163	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	165	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/linux/fs.rs	175	native_path	libc::	process	host_mechanic
 crates/fbuild-core/src/platform/linux/ipc.rs	1	native_path	interprocess::local_socket	ipc	host_mechanic
 crates/fbuild-core/src/platform/linux/ipc.rs	2	native_path	interprocess::local_socket	ipc	host_mechanic
 crates/fbuild-core/src/platform/linux/ipc.rs	3	native_path	interprocess::os::unix	ipc	host_mechanic
@@ -25,13 +29,17 @@ crates/fbuild-core/src/platform/linux/ipc.rs	66	native_path	std::os::unix::fs::P
 crates/fbuild-core/src/platform/linux/mod.rs	14	compile_host_fact	std::env::consts::ARCH	host	host_mechanic
 crates/fbuild-core/src/platform/linux/process.rs	1	native_path	std::os::unix::process::ExitStatusExt	process	host_mechanic
 crates/fbuild-core/src/platform/macos/fs.rs	2	native_path	std::os::unix::fs::PermissionsExt	fs	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	13	native_path	std::os::unix::fs::MetadataExt	fs	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	57	native_path	std::os::unix::fs::symlink	fs	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	61	native_path	std::os::unix::fs::symlink	fs	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	105	native_path	std::os::unix::ffi::OsStrExt	process	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	110	native_path	libc::	process	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	112	native_path	libc::	process	host_mechanic
-crates/fbuild-core/src/platform/macos/fs.rs	122	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	31	native_path	std::os::unix::fs	fs	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	51	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	51	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	54	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	68	native_path	std::os::unix::fs::MetadataExt	fs	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	112	native_path	std::os::unix::fs::symlink	fs	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	116	native_path	std::os::unix::fs::symlink	fs	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	158	native_path	std::os::unix::ffi::OsStrExt	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	163	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	165	native_path	libc::	process	host_mechanic
+crates/fbuild-core/src/platform/macos/fs.rs	175	native_path	libc::	process	host_mechanic
 crates/fbuild-core/src/platform/macos/ipc.rs	1	native_path	interprocess::local_socket	ipc	host_mechanic
 crates/fbuild-core/src/platform/macos/ipc.rs	2	native_path	interprocess::local_socket	ipc	host_mechanic
 crates/fbuild-core/src/platform/macos/ipc.rs	3	native_path	socket2::	ipc	host_mechanic
@@ -47,18 +55,65 @@ crates/fbuild-core/src/platform/windows/device.rs	35	native_path	windows_sys::	p
 crates/fbuild-core/src/platform/windows/fs.rs	2	native_path	std::os::windows::ffi::OsStrExt	process	host_mechanic
 crates/fbuild-core/src/platform/windows/fs.rs	3	native_path	std::os::windows::fs	fs	host_mechanic
 crates/fbuild-core/src/platform/windows/fs.rs	4	native_path	std::os::windows::io::AsRawHandle	process	host_mechanic
-crates/fbuild-core/src/platform/windows/fs.rs	60	native_path	std::os::windows::fs::symlink_dir	fs	host_mechanic
-crates/fbuild-core/src/platform/windows/fs.rs	64	native_path	std::os::windows::fs::symlink_file	fs	host_mechanic
-crates/fbuild-core/src/platform/windows/fs.rs	92	native_path	windows_sys::	process	host_mechanic
-crates/fbuild-core/src/platform/windows/fs.rs	147	native_path	windows_sys::	process	host_mechanic
-crates/fbuild-core/src/platform/windows/fs.rs	191	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	12	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	16	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	38	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	47	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	81	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	82	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	116	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	156	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	260	native_path	std::os::windows::fs::symlink_dir	fs	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	264	native_path	std::os::windows::fs::symlink_file	fs	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	292	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	352	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	394	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	405	attr_cfg	#[cfg(windows)]	host	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	417	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	418	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	438	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	439	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/fs.rs	458	native_path	windows_sys::	process	host_mechanic
 crates/fbuild-core/src/platform/windows/ipc.rs	1	native_path	interprocess::local_socket	ipc	host_mechanic
 crates/fbuild-core/src/platform/windows/ipc.rs	2	native_path	interprocess::local_socket	ipc	host_mechanic
 crates/fbuild-core/src/platform/windows/ipc.rs	3	native_path	interprocess::os::windows	ipc	host_mechanic
 crates/fbuild-core/src/platform/windows/ipc.rs	4	native_path	interprocess::os::windows	ipc	host_mechanic
 crates/fbuild-core/src/platform/windows/ipc.rs	5	native_path	socket2::	ipc	host_mechanic
 crates/fbuild-core/src/platform/windows/ipc.rs	6	native_path	std::os::windows::io::AsRawSocket	ipc	host_mechanic
-crates/fbuild-core/src/platform/windows/mod.rs	13	compile_host_fact	std::env::consts::ARCH	host	host_mechanic
+crates/fbuild-core/src/platform/windows/mod.rs	14	compile_host_fact	std::env::consts::ARCH	host	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	3	native_path	std::os::windows::ffi::OsStrExt	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	8	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	13	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	23	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	30	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	32	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	36	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	37	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	38	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	55	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	81	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	85	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	180	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	181	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	222	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	232	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	250	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	251	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	287	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	290	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	363	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	377	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	385	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	386	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	387	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	493	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	494	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	537	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	538	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	568	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	599	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	600	native_path	windows_sys::	process	host_mechanic
+crates/fbuild-core/src/platform/windows/private_directory.rs	604	native_path	windows_sys::	process	host_mechanic
 crates/fbuild-core/src/platform/windows/process.rs	87	native_path	std::os::windows::ffi::OsStrExt	process	host_mechanic
 crates/fbuild-core/src/platform/windows/process.rs	89	native_path	windows_sys::	process	host_mechanic
 crates/fbuild-core/src/platform/windows/process.rs	92	native_path	windows_sys::	process	host_mechanic

crates/fbuild-build-engine/src/compiler.rs

@@ -591,6 +591,9 @@ pub async fn compile_source(
     let output_buf = absolute_from_cwd(output);
     let source = source_buf.as_path();
     let output = output_buf.as_path();
+    for path in [compiler, source, output] {
+        fbuild_paths::long_paths::validate_legacy_path(path)?;
+    }
 
     if let Some(parent) = output.parent() {
         std::fs::create_dir_all(parent)?;

crates/fbuild-build-engine/src/pipeline/context.rs

@@ -109,6 +109,9 @@ impl BuildContext {
     ) -> Result<Self> {
         let project_dir = &params.project_dir;
         let env_name = &params.env_name;
+        fbuild_paths::long_paths::validate_legacy_path(project_dir)?;
+        fbuild_paths::long_paths::validate_legacy_path(&params.build_dir)?;
+        fbuild_paths::long_paths::prepare_build_directory(&params.build_dir)?;
 
         // 1. Parse platformio.ini, attaching any forwarded `PLATFORMIO_*` env
         // var overrides from the CLI caller (the daemon does not inherit

crates/fbuild-cli/build.rs

@@ -10,5 +10,13 @@ fn main() {
     let target = std::env::var("TARGET").unwrap_or_default();
     if target.contains("pc-windows-msvc") {
         println!("cargo:rustc-link-arg-bin=fbuild=/STACK:8388608");
+        let manifest = std::path::Path::new(&std::env::var("CARGO_MANIFEST_DIR").unwrap())
+            .join("../fbuild-core/src/platform/windows/long-paths.manifest");
+        println!("cargo:rerun-if-changed={}", manifest.display());
+        println!("cargo:rustc-link-arg-bin=fbuild=/MANIFEST:EMBED");
+        println!(
+            "cargo:rustc-link-arg-bin=fbuild=/MANIFESTINPUT:{}",
+            manifest.display()
+        );
     }
 }

crates/fbuild-cli/src/cli/README.md

@@ -26,4 +26,5 @@ here and is dispatched from `cli::async_main`.
 - **`reset.rs`** -- `run_reset`
 - **`lnk.rs`** -- `run_lnk` (pull / check / add)
 - **`install.rs`** -- `run_install`: in-process `fbuild install` over `fbuild_build::provision_env`, text / JSON rendering, `--check` exit codes (FastLED/fbuild#1433)
+- **`windows_long_paths.rs`** -- Windows preflight, explicit UAC repair, fresh command restart, and graceful daemon handoff (#1673)
 - **`tests.rs`** -- unit tests for argument normalization and `fbuild ci` parsing

crates/fbuild-cli/src/cli/args.rs

@@ -116,6 +116,14 @@ pub struct Cli {
     /// (`CI=true`) is auto-suppressed. See FastLED/fbuild#626.
     #[arg(long = "no-update-check")]
     pub no_update_check: bool,
+
+    /// Enable Windows long paths with administrator approval (UAC)
+    #[arg(long, global = true)]
+    pub fix_win: bool,
+
+    /// Fixed, one-shot registry repair helper; never starts a daemon.
+    #[arg(long = "__fix-win-helper", hide = true, conflicts_with = "fix_win")]
+    pub fix_win_helper: bool,
 }
 
 #[derive(Subcommand)]