Problem: can't build linux package under macOS

The problem is generally solved by running inside the specialized `pgpm`
container which has necessary dependencies installed.

However, this requires us to run it there.

Solution: podmanize everything!

We already use podman to bring components we may not have – like rust
toolchain. Why not use it to bring `mock` in?

This is not perfect yet, and relies on volume mapping (which is what we do
already anyway) – for which we had to do special accommodations to ensure
we know these paths and they are absolute.

We currently use the `pgpm` image as the one that should contain `mock`. But
may be it should be a different, smaller image?

To build for a particular OS, use the `--os` flag, for example:

```
--os rocky+epel-9
```

exe/pgpm

@@ -34,7 +34,7 @@ module Pgpm
 
         include SharedOptions
 
-        option :os, type: :string, default: Pgpm::OS.auto_detect.name, desc: "OS name"
+        option :os, type: :string, default: Pgpm::OS.auto_detect&.name, desc: "OS name"
         option :arch, type: :string, default: Pgpm::Arch.host.name, desc: "Target architecture"
         option :pgdist, type: :string, default: "pgdg", desc: "Target Postgres distribution"
         option :pgver, type: :string, default: Pgpm::Postgres::Distribution.versions.last.to_s, desc: "Target Postgres version"
@@ -71,7 +71,7 @@ module Pgpm
             pkg
           end
 
-          os = Pgpm::OS.auto_detect
+          os = os ? Pgpm::OS.find(os) : Pgpm::OS.auto_detect
           arch = if arch
                    Pgpm::Arch.new(arch)
                  else

lib/pgpm/arch.rb

@@ -14,7 +14,7 @@ def self.in_scope
     end
 
     def initialize(name)
-      @name = name
+      @name = name == "arm64" ? "aarch64" : name
     end
 
     attr_reader :name

lib/pgpm/os.rb

@@ -42,6 +42,10 @@ def self.auto_detect
       Pgpm::OS::Linux.auto_detect
     end
 
+    def self.find(name)
+      Base.all_subclasses.find { |klass| klass.name == name }&.new
+    end
+
     def self.in_scope
       LSpace[:pgpm_target_operating_system]
     end

lib/pgpm/rpm/mock/operation.rb

@@ -12,10 +12,13 @@ def self.buildsrpm(spec, sources, config: nil, result_dir: nil, cb: nil)
           ]
           args.push("--sources", sources) if sources
           args.push("-r", config.to_s) unless config.nil?
-          new(*args, cb: lambda {
+          paths = [buffer_result_dir]
+          paths.push(File.dirname(spec))
+          paths.push(File.dirname(sources)) if sources
+          new(*args, paths:, cb: lambda {
             rpms = Dir.glob("*.rpm", base: buffer_result_dir).map do |f|
               FileUtils.cp(Pathname(buffer_result_dir).join(f), result_dir) unless result_dir.nil?
-              f
+              File.join(File.absolute_path(result_dir), f)
             end
             FileUtils.rm_rf(buffer_result_dir)
             cb.call unless cb.nil?
@@ -29,22 +32,25 @@ def self.rebuild(srpm, config: nil, result_dir: nil, cb: nil)
             "--rebuild", "--chain", "--recurse", srpm, "--localrepo", buffer_result_dir
           ]
           args.push("-r", config.to_s) unless config.nil?
-          new(*args, cb: lambda {
+          paths = [buffer_result_dir]
+          paths.push(File.dirname(srpm))
+          new(*args, paths:, cb: lambda {
             # Here we glob for **/*.rpm as ``--localrepo` behaves differently from
             # `--resultdir`
             rpms = Dir.glob("**/*.rpm", base: buffer_result_dir).map do |f|
               FileUtils.cp(Pathname(buffer_result_dir).join(f), result_dir) unless result_dir.nil?
-              f
+              File.join(File.absolute_path(result_dir), f)
             end
             FileUtils.rm_rf(buffer_result_dir)
             cb.call unless cb.nil?
             rpms
           })
         end
 
-        def initialize(*args, opts: nil, cb: nil)
+        def initialize(*args, opts: nil, paths: [], cb: nil)
           @args = args
           @cb = cb
+          @paths = paths
           @opts = opts || { "print_main_output" => "True", "pgdg_version" => Postgres::Distribution.in_scope.major_version }
         end
 
@@ -53,7 +59,8 @@ def initialize(*args, opts: nil, cb: nil)
         def call
           options = @opts.flat_map { |(k, v)| ["--config-opts", "#{k}=#{v}"] }.compact.join(" ")
           command = "mock #{options} #{@args.join(" ")}"
-          raise "Failed to execute `#{command}`" unless system command
+          map_paths = @paths.map { |p| "-v #{p}:#{p}" }.join(" ")
+          raise "Failed to execute `#{command}`" unless Podman.run("run -v #{Dir.pwd}:#{Dir.pwd} #{map_paths} --privileged -ti ghcr.io/postgres-pm/pgpm #{command}")
 
           @cb&.call
         end