less: use the real terminal capability stack

Formula/less.rb

@@ -0,0 +1,82 @@
+require (Tap.fetch("automattic", "kandelo-homebrew").path/"Kandelo/formula_support/kandelo_formula_support").to_s
+
+class Less < Formula
+  include KandeloFormulaSupport
+
+  desc "Terminal pager for Kandelo"
+  homepage "https://www.greenwoodsoftware.com/less/"
+  url "https://www.greenwoodsoftware.com/less/less-668.tar.gz"
+  sha256 "2819f55564d86d542abbecafd82ff61e819a3eec967faa36cd3e68f1596a44b8"
+  license "GPL-3.0-or-later"
+
+  depends_on "automattic/kandelo-homebrew/ncurses"
+
+  skip_clean "bin/less", "bin/lesskey", "bin/lessecho"
+
+  def install
+    kandelo_require_arch!("wasm32")
+    ncurses = formula_opt_prefix("automattic/kandelo-homebrew/ncurses")
+
+    kandelo_wasm_build do |root|
+      ENV["CPPFLAGS"] = "-I#{ncurses}/include"
+      ENV["LDFLAGS"] = "-L#{ncurses}/lib"
+
+      system kandelo_configure, *kandelo_std_configure_args, "--with-regex=posix"
+      # Less compiles BINDIR and SYSDIR into the pager for system lesskey
+      # files. Use the stable opt path there while leaving the install target
+      # at the versioned keg configured above.
+      system "make", "-j#{ENV.make_jobs}", "bindir=#{opt_bin}", "sysconfdir=#{opt_prefix}/etc"
+
+      instrumented = buildpath/"less.instrumented"
+      system "#{root}/scripts/run-wasm-fork-instrument.sh", buildpath/"less", "-o", instrumented
+      mv instrumented, buildpath/"less"
+
+      system "make", "install"
+    end
+  end
+
+  test do
+    assert_path_exists bin/"less"
+    assert_path_exists bin/"lesskey"
+    assert_path_exists bin/"lessecho"
+    assert_path_exists man1/"less.1"
+    assert_path_exists man1/"lesskey.1"
+    assert_path_exists man1/"lessecho.1"
+
+    assert_match(/^less 668 \(POSIX regular expressions\)$/, kandelo_run_wasm(bin/"less", ["--version"]).lines.first)
+    assert_match(/^lesskey  version 668$/, kandelo_run_wasm(bin/"lesskey", ["--version"]).lines.first)
+    assert_equal "alpha\\ beta plain\n",
+      kandelo_run_wasm(bin/"lessecho", ["-m ", "alpha beta", "plain"])
+
+    input = testpath/"input.txt"
+    input.write "alpha\nbeta\ngamma\n"
+    env = {
+      "HOME"       => testpath,
+      "KERNEL_CWD" => testpath,
+      "TERM"       => "xterm-256color",
+      "TERMINFO"   => testpath/"empty-terminfo",
+    }
+    (testpath/"empty-terminfo").mkpath
+    assert_equal input.read,
+      kandelo_run_wasm(bin/"less", ["-F", "-X", input.basename], env: env)
+
+    filter_env = env.merge(
+      "LESSOPEN" => "|echo filtered:%s",
+      "SHELL"    => "/bin/sh",
+    )
+    assert_equal "filtered:input.txt\n",
+      kandelo_run_wasm(bin/"less", ["-F", "-X", input.basename], env: filter_env)
+
+    # The terminal implementation must come from the ncurses keg. This also
+    # guards against restoring the registry recipe's fake termcap library.
+    ncurses = formula_opt_prefix("automattic/kandelo-homebrew/ncurses")
+    less_bytes = File.binread(bin/"less")
+    assert_includes less_bytes, "#{ncurses}/share/terminfo"
+    assert_includes less_bytes, "#{opt_bin}/.sysless"
+    assert_includes less_bytes, "#{opt_prefix}/etc/sysless"
+    assert_includes less_bytes, "#{opt_prefix}/etc/syslesskey"
+    [bin/"less", bin/"lesskey", bin/"lessecho"].each do |command|
+      refute_includes File.binread(command), prefix.to_s
+    end
+  end
+end

README.md

@@ -28,6 +28,7 @@ Current migration controls and pilots include:
 - `libcurl`, the TLS, compression, threaded-resolver, and Unix-socket transfer library;
 - `curl`, the matching command-line transfer client linked against the tap library;
 - `ncurses`, the wide-character terminal library and CLI dependency root;
+- `less`, the terminal pager linked against the tap's real ncurses termcap interface;
 - `sed`, the GNU stream-editing CLI used by shell and build workflows;
 - `gzip`, the GNU compression CLI with native gunzip and zcat aliases;
 - `grep`, GNU regular-expression and file search for the leaf CLI wave;