appveyor: small fixes

* Add forgotten --eol argument to 'git ls-files'. Without it, in certain
  edge cases, files might have their mtime restored when it shouldn't.
* Don't parse ls-files output into fields; it's unnecessary.
* Disable the pip cache dir, and stop saving it to the appveyor cache.
* Leverage the 'git -C «dir»' flag to make a script shorter.
* Fix some factually and/or grammatically incorrect comments.

.appveyor.yml

@@ -133,11 +133,11 @@ environment:
  function Stop-TraceFilesNeeded {
  # Look for files that had their atime changed, and mark them needed.
  Set-FilesNeeded -Auto
- # Make a list of all files to delete, then delete them.
+ # Make a list of all files to delete.
  $files = $not_needed.Keys |
  where { Test-Path $_ -PathType Leaf } |
  foreach { Get-Item $_ -Force }
- # Compute the total size of all deleted files.
+ # Compute the total size of all to-be-deleted files.
  $size_info = $files | measure -Property Length -Sum
  $size_mb = "{0:N1}" -f ($size_info.Sum / (1024 * 1024))
  # Delete files, as well as parent directories if they became empty.
@@ -147,7 +147,7 @@ environment:
  }
  # All unnecessary files are now gone.
  $not_needed.Clear()
- # Log about what what was cleaned up.
+ # Summarize what was cleaned up in the build log.
  if ($files.Count -gt 0) {
  Write-Host "Deleted $($files.Count) unnecessary files and",
  "$($dirs.Count) directories ($size_mb MB)."
@@ -172,23 +172,19 @@ environment:
  $dirty = git status -z --ignore-submodules=all --untracked-files=no
  if ($dirty) { throw "Work tree dirty." }
  # Ask git for a list of checked-out files and their hashes, metadata.
- # Include regular files only (mode 100644/100755), no symlinks etc.
- (git ls-files -z --stage --full-name) -split "\0" |
- Select-String "^100" |
- foreach {
- # Parse git output.
- $metadata, $path = $_ -split "\t", 2
- $mode, $sha, $null, $eol_info = $metadata -split "\s+"
- # Compute cache key.
- $key = $path, $mode, $sha, $eol_info -join ","
+ (git ls-files -z --stage --eol --full-name) -split "\0" | foreach {
+ # Skip non-files (symlinks etc.). File mode should be 100644/100755.
+ if ($_ -notmatch "^100") { return }
  # Look up mtime in cache. Reset to 'now' if not found or invalid.
- $mtime = $old_cache[$key]
+ # The entire "mode hash attr filename" line serves as the cache key.
+ $mtime = $old_cache[$_]
  if (-not $mtime -or $mtime -gt $now) { $mtime = $now }
- # Change file mtime.
- $dt = [DateTime]::FromFileTimeUtc($mtime)
- Set-ItemProperty -Path $path -Name LastWriteTime -Value $dt -Force
+ # Change the file's LastWriteTime to the mtime found in the cache.
+ $path = ($_ -split "\t", 3)[2] # Filename starts after 2nd tab.
+ $lwt = [DateTime]::FromFileTimeUtc($mtime)
+ Set-ItemProperty -Path $path -Name LastWriteTime -Value $lwt -Force
  # Add entry to updated cache.
- $new_cache[$key] = $mtime
+ $new_cache[$_] = $mtime
  }
  # Write the updated cache back to disk.
  if (Get-SaveCache) {
@@ -225,9 +221,8 @@ for:
  APPVEYOR_CACHE_SKIP_SAVE: true
 
 cache:
- # Python packages installed with `pip --user` and Pip cache.
+ # Python packages installed with `pip --user`.
  - $(APPDATA)\Python
- - $(LOCALAPPDATA)\pip
  # Rust stuff.
  - $(CARGO_HOME)
  - $(RUSTUP_HOME)
@@ -262,12 +257,7 @@ install:
  # Prune and pack git objects. Thus when we upload `.git/modules/` to the
  # Appveyor cache, it'll include only objects that were actually needed.
  # This step is skipped if the cache is not going to be saved.
- - ps: |-
- if (Get-SaveCache) {
- Push-Location $env:DENO_THIRD_PARTY_PATH
- Exec { & git gc --prune=all }
- Pop-Location
- }
+ - ps: if (Get-SaveCache) { git -C $env:DENO_THIRD_PARTY_PATH gc --prune=all }
 
  # Git doesn't store file mtimes, so those are stored separately in the cache.
  # Without it, ninja will assume all files are dirty and rebuild everything.
@@ -297,10 +287,10 @@ install:
  $env:PATH = $p -join ";"
 
  # Pip on Appveyor is too old. Install a recent version in our user dir.
- - python -m pip install --upgrade --user pip
+ - python -m pip install --upgrade --user --no-cache-dir pip
 
  # Install Python packages.
- - pip install --upgrade --user pywin32 yapf
+ - pip install --upgrade --user --no-cache-dir pywin32 yapf
 
  # Add Rust/Cargo to PATH.
  - ps: $env:PATH += ";$env:CARGO_HOME\bin"
@@ -384,7 +374,7 @@ after_test:
  - ps: |-
  $out = ninja -C $env:DENO_BUILD_PATH -n -d explain
  if ($out -notcontains "ninja: no work to do.") {
- throw "Build should be up-to-date but isnt't."
+ throw "Build should be up-to-date but isn't."
  }
 
  # Verify that generated ninja files do not use absolute path names.