refactor: simplify linker & receipt writing (#1033)

7 files changed, 152 insertions, 142 deletions

diff --git a/lua/mason-core/installer/context.lua b/lua/mason-core/installer/context.lua
index 8acfa5ef..93fe688b 100644
--- a/lua/mason-core/installer/context.lua
+++ b/lua/mason-core/installer/context.lua
@@ -148,7 +148,7 @@ end
 ---@field public cwd CwdManager
 ---@field public opts PackageInstallOpts
 ---@field public stdio_sink StdioSink
----@field links { bin: table<string, string>, share: table<string, string> }
+---@field links { bin: table<string, string>, share: table<string, string>, opt: table<string, string> }
 local InstallContext = {}
 InstallContext.__index = InstallContext
 
@@ -168,6 +168,7 @@ function InstallContext.new(handle, opts)
         links = {
             bin = {},
             share = {},
+            opt = {},
         },
         opts = opts,
     }, InstallContext)
@@ -327,11 +328,4 @@ function InstallContext:link_bin(executable, rel_path)
     return self
 end
 
----@param rel_dest string
----@param rel_source string
-function InstallContext:link_share(rel_dest, rel_source)
-    self.links.share[rel_dest] = rel_source
-    return self
-end
-
 return InstallContext
diff --git a/lua/mason-core/installer/init.lua b/lua/mason-core/installer/init.lua
index 8e05cb20..9f150269 100644
--- a/lua/mason-core/installer/init.lua
+++ b/lua/mason-core/installer/init.lua
@@ -34,16 +34,14 @@ end
 
 ---@async
 ---@param context InstallContext
-local function write_receipt(context)
+local function build_receipt(context)
     return Result.pcall(function()
-        log.fmt_debug("Writing receipt for %s", context.package)
-        context.receipt
+        log.fmt_debug("Building receipt for %s", context.package)
+        return context.receipt
             :with_name(context.package.name)
             :with_schema_version("1.1")
             :with_completion_time(vim.loop.gettimeofday())
-        local receipt_path = path.concat { context.cwd:get(), "mason-receipt.json" }
-        local install_receipt = context.receipt:build()
-        fs.async.write_file(receipt_path, vim.json.encode(install_receipt))
+            :build()
     end)
 end
 
@@ -176,8 +174,12 @@ function M.execute(handle, opts)
         -- 4. link package
         try(linker.link(context))
 
-        -- 5. write receipt
-        try(write_receipt(context))
+        -- 5. build & write receipt
+        ---@type InstallReceipt
+        local receipt = try(build_receipt(context))
+        try(Result.pcall(function()
+            receipt:write(context.cwd:get())
+        end))
     end)
         :on_success(function()
             permit:forget()
@@ -205,8 +207,12 @@ function M.execute(handle, opts)
                 )
             end
 
-            -- unlink linked executables (in the rare occasion an error occurs after linking)
-            linker.unlink(context.package, context.receipt)
+            -- unlink linked executables (in the occasion an error occurs after linking)
+            build_receipt(context):on_success(function(receipt)
+                linker.unlink(context.package, receipt):on_failure(function(err)
+                    log.error("Failed to unlink failed installation", err)
+                end)
+            end)
 
             if not handle:is_closed() and not handle.is_terminated then
                 handle:close()
diff --git a/lua/mason-core/installer/linker.lua b/lua/mason-core/installer/linker.lua
index 6de95160..529df563 100644
--- a/lua/mason-core/installer/linker.lua
+++ b/lua/mason-core/installer/linker.lua
@@ -8,141 +8,136 @@ local a = require "mason-core.async"
 
 local M = {}
 
----@param receipt InstallReceipt
-local function unlink_bin(receipt)
-    local bin = receipt.links.bin
-    if not bin then
-        return
-    end
-    -- Windows executables did not include file extension in bin receipts on 1.0.
-    local should_append_cmd = platform.is.win and receipt.schema_version == "1.0"
-    for executable in pairs(bin) do
-        if should_append_cmd then
-            executable = executable .. ".cmd"
-        end
-        local bin_path = path.bin_prefix(executable)
-        fs.sync.unlink(bin_path)
-    end
-end
+---@alias LinkContext { type: '"bin"' | '"opt"' | '"share"', prefix: fun(path: string): string }
+
+---@type table<'"BIN"' | '"OPT"' | '"SHARE"', LinkContext>
+local LinkContext = {
+    BIN = { type = "bin", prefix = path.bin_prefix },
+    OPT = { type = "opt", prefix = path.opt_prefix },
+    SHARE = { type = "share", prefix = path.share_prefix },
+}
 
 ---@param receipt InstallReceipt
-local function unlink_share(receipt)
-    local share = receipt.links.share
-    if not share then
-        return
-    end
-    for share_file in pairs(share) do
-        local bin_path = path.share_prefix(share_file)
-        fs.sync.unlink(bin_path)
-    end
+---@param link_context LinkContext
+local function unlink(receipt, link_context)
+    return Result.pcall(function()
+        local links = receipt.links[link_context.type]
+        if not links then
+            return
+        end
+        for linked_file in pairs(links) do
+            if receipt.schema_version == "1.0" and link_context == LinkContext.BIN and platform.is.win then
+                linked_file = linked_file .. ".cmd"
+            end
+            local share_path = link_context.prefix(linked_file)
+            fs.sync.unlink(share_path)
+        end
+    end)
 end
 
 ---@param pkg Package
 ---@param receipt InstallReceipt
+---@nodiscard
 function M.unlink(pkg, receipt)
     log.fmt_debug("Unlinking %s", pkg, receipt.links)
-    unlink_bin(receipt)
-    unlink_share(receipt)
-end
-
----@async
----@param context InstallContext
-local function link_bin(context)
     return Result.try(function(try)
-        local links = context.links.bin
-        local pkg = context.package
-        for name, rel_path in pairs(links) do
-            if platform.is.win then
-                name = ("%s.cmd"):format(name)
-            end
-            local target_abs_path = path.concat { pkg:get_install_path(), rel_path }
-            local bin_path = path.bin_prefix(name)
-
-            if not context.opts.force and fs.async.file_exists(bin_path) then
-                return Result.failure(("bin/%s is already linked."):format(name))
-            end
-            if not fs.async.file_exists(target_abs_path) then
-                return Result.failure(("Link target %q does not exist."):format(target_abs_path))
-            end
-
-            log.fmt_debug("Linking bin %s to %s", name, target_abs_path)
-
-            platform.when {
-                unix = function()
-                    try(Result.pcall(fs.async.symlink, target_abs_path, bin_path))
-                end,
-                win = function()
-                    -- We don't "symlink" on Windows because:
-                    -- 1) .LNK is not commonly found in PATHEXT
-                    -- 2) some executables can only run from their true installation location
-                    -- 3) many utilities only consider .COM, .EXE, .CMD, .BAT files as candidates by default when resolving executables (e.g. neovim's |exepath()| and |executable()|)
-                    try(Result.pcall(
-                        fs.async.write_file,
-                        bin_path,
-                        _.dedent(([[
-                        @ECHO off
-                        GOTO start
-                        :find_dp0
-                        SET dp0=%%~dp0
-                        EXIT /b
-                        :start
-                        SETLOCAL
-                        CALL :find_dp0
-
-                        endLocal & goto #_undefined_# 2>NUL || title %%COMSPEC%% & "%s" %%*
-                ]]):format(target_abs_path))
-                    ))
-                end,
-            }
-            context.receipt:with_link("bin", name, rel_path)
-        end
+        try(unlink(receipt, LinkContext.BIN))
+        try(unlink(receipt, LinkContext.SHARE))
+        try(unlink(receipt, LinkContext.OPT))
     end)
 end
 
 ---@async
 ---@param context InstallContext
-local function link_share(context)
+---@param link_context LinkContext
+---@param link_fn async fun(dest: string, target: string): Result
+local function link(context, link_context, link_fn)
+    log.trace("Linking", context.package, link_context.type, context.links[link_context.type])
     return Result.try(function(try)
-        for name, rel_path in pairs(context.links.share) do
-            local dest = path.share_prefix(name)
+        for name, rel_path in pairs(context.links[link_context.type]) do
+            if platform.is.win and link_context == LinkContext.BIN then
+                name = ("%s.cmd"):format(name)
+            end
+            local dest_abs_path = link_context.prefix(name)
+            local target_abs_path = path.concat { context.package:get_install_path(), rel_path }
 
             do
+                -- 1. Ensure destination directory exists
                 if vim.in_fast_event() then
                     a.scheduler()
                 end
 
-                local dir = vim.fn.fnamemodify(dest, ":h")
+                local dir = vim.fn.fnamemodify(dest_abs_path, ":h")
                 if not fs.async.dir_exists(dir) then
                     try(Result.pcall(fs.async.mkdirp, dir))
                 end
             end
 
-            local target_abs_path = path.concat { context.package:get_install_path(), rel_path }
-
-            if context.opts.force then
-                if fs.async.file_exists(dest) then
-                    try(Result.pcall(fs.async.unlink, dest))
+            do
+                -- 2. Ensure source file exists and target doesn't yet exist OR if --force unlink target if it already
+                -- exists.
+                if context.opts.force then
+                    if fs.async.file_exists(dest_abs_path) then
+                        try(Result.pcall(fs.async.unlink, dest_abs_path))
+                    end
+                elseif fs.async.file_exists(dest_abs_path) then
+                    return Result.failure(("%q is already linked."):format(dest_abs_path, name))
+                end
+                if not fs.async.file_exists(target_abs_path) then
+                    return Result.failure(("Link target %q does not exist."):format(target_abs_path))
                 end
-            elseif fs.async.file_exists(dest) then
-                return Result.failure(("share/%s is already linked."):format(name))
-            end
-            if not fs.async.file_exists(target_abs_path) then
-                return Result.failure(("Link target %q does not exist."):format(target_abs_path))
             end
 
-            try(Result.pcall(fs.async.symlink, target_abs_path, dest))
-            context.receipt:with_link("share", name, rel_path)
+            -- 3. Execute link.
+            try(link_fn(dest_abs_path, target_abs_path))
+            context.receipt:with_link(link_context.type, name, rel_path)
         end
     end)
 end
 
+---@param context InstallContext
+---@param link_context LinkContext
+local function symlink(context, link_context)
+    return link(context, link_context, function(target, dest)
+        return Result.pcall(fs.async.symlink, dest, target)
+    end)
+end
+
+---@param context InstallContext
+local function win_bin_wrapper(context)
+    return link(context, LinkContext.BIN, function(dest, target)
+        return Result.pcall(
+            fs.async.write_file,
+            dest,
+            _.dedent(([[
+                @ECHO off
+                GOTO start
+                :find_dp0
+                SET dp0=%%~dp0
+                EXIT /b
+                :start
+                SETLOCAL
+                CALL :find_dp0
+
+                endLocal & goto #_undefined_# 2>NUL || title %%COMSPEC%% & "%s" %%*
+            ]]):format(target))
+        )
+    end)
+end
+
 ---@async
 ---@param context InstallContext
+---@nodiscard
 function M.link(context)
     log.fmt_debug("Linking %s", context.package)
     return Result.try(function(try)
-        try(link_bin(context))
-        try(link_share(context))
+        if platform.is.win then
+            try(win_bin_wrapper(context))
+        else
+            try(symlink(context, LinkContext.BIN))
+        end
+        try(symlink(context, LinkContext.SHARE))
+        try(symlink(context, LinkContext.OPT))
     end)
 end
 
diff --git a/lua/mason-core/package/init.lua b/lua/mason-core/package/init.lua
index a7ee6f14..05d72751 100644
--- a/lua/mason-core/package/init.lua
+++ b/lua/mason-core/package/init.lua
@@ -153,7 +153,7 @@ function Package:unlink()
     local install_path = self:get_install_path()
     -- 1. Unlink
     self:get_receipt():if_present(function(receipt)
-        linker.unlink(self, receipt)
+        linker.unlink(self, receipt):get_or_throw()
     end)
 
     -- 2. Remove installation artifacts
diff --git a/lua/mason-core/path.lua b/lua/mason-core/path.lua
index 6a4c5663..b63b6c4a 100644
--- a/lua/mason-core/path.lua
+++ b/lua/mason-core/path.lua
@@ -38,9 +38,14 @@ function M.bin_prefix(executable)
     return M.concat { M.install_prefix "bin", executable }
 end
 
----@param share string?
-function M.share_prefix(share)
-    return M.concat { M.install_prefix "share", share }
+---@param file string?
+function M.share_prefix(file)
+    return M.concat { M.install_prefix "share", file }
+end
+
+---@param file string?
+function M.opt_prefix(file)
+    return M.concat { M.install_prefix "opt", file }
 end
 
 ---@param name string?
diff --git a/lua/mason-core/receipt.lua b/lua/mason-core/receipt.lua
index 281d7148..4beeb6aa 100644
--- a/lua/mason-core/receipt.lua
+++ b/lua/mason-core/receipt.lua
@@ -25,6 +25,33 @@ local M = {}
 ---@class InstallReceiptLinks
 ---@field bin? table<string, string>
 ---@field share? table<string, string>
+---@field opt? table<string, string>
+
+---@class InstallReceipt<T> : { primary_source: T }
+---@field public name string
+---@field public schema_version InstallReceiptSchemaVersion
+---@field public metrics {start_time:integer, completion_time:integer}
+---@field public primary_source InstallReceiptSource
+---@field public secondary_sources InstallReceiptSource[]
+---@field public links InstallReceiptLinks
+local InstallReceipt = {}
+InstallReceipt.__index = InstallReceipt
+
+function InstallReceipt.new(data)
+    return setmetatable(data, InstallReceipt)
+end
+
+function InstallReceipt.from_json(json)
+    return InstallReceipt.new(json)
+end
+
+---@async
+---@param cwd string
+function InstallReceipt:write(cwd)
+    local path = require "mason-core.path"
+    local fs = require "mason-core.fs"
+    fs.async.write_file(path.concat { cwd, "mason-receipt.json" }, vim.json.encode(self))
+end
 
 ---@class InstallReceiptBuilder
 ---@field private secondary_sources InstallReceiptSource[]
@@ -39,6 +66,7 @@ function InstallReceiptBuilder.new()
         links = {
             bin = vim.empty_dict(),
             share = vim.empty_dict(),
+            opt = vim.empty_dict(),
         },
     }, InstallReceiptBuilder)
 end
@@ -67,7 +95,7 @@ function InstallReceiptBuilder:with_secondary_source(source)
     return self
 end
 
----@param typ '"bin"' | '"share"'
+---@param typ '"bin"' | '"share"' | '"opt"'
 ---@param name string
 ---@param rel_path string
 function InstallReceiptBuilder:with_link(typ, name, rel_path)
@@ -104,7 +132,7 @@ function InstallReceiptBuilder:build()
     assert(self.start_time, "start_time is required")
     assert(self.completion_time, "completion_time is required")
     assert(self.primary_source, "primary_source is required")
-    return {
+    return InstallReceipt.new {
         name = self.name,
         schema_version = self.schema_version,
         metrics = {
@@ -162,24 +190,6 @@ function InstallReceiptBuilder.git_remote(remote_url)
     return { type = "git", remote = remote_url }
 end
 
----@class InstallReceipt<T> : { primary_source: T }
----@field public name string
----@field public schema_version InstallReceiptSchemaVersion
----@field public metrics {start_time:integer, completion_time:integer}
----@field public primary_source InstallReceiptSource
----@field public secondary_sources InstallReceiptSource[]
----@field public links InstallReceiptLinks
-local InstallReceipt = {}
-InstallReceipt.__index = InstallReceipt
-
-function InstallReceipt.new(props)
-    return setmetatable(props, InstallReceipt)
-end
-
-function InstallReceipt.from_json(json)
-    return InstallReceipt.new(json)
-end
-
 M.InstallReceiptBuilder = InstallReceiptBuilder
 M.InstallReceipt = InstallReceipt
 
diff --git a/lua/mason-core/result.lua b/lua/mason-core/result.lua
index f3b76339..1491c31f 100644
--- a/lua/mason-core/result.lua
+++ b/lua/mason-core/result.lua
@@ -176,9 +176,9 @@ function Result.run_catching(fn)
     end
 end
 
----@generic V
----@param fn fun(try: fun(result: Result): any): V
----@return Result # Result<V>
+---@generic T
+---@param fn fun(try: fun(result: Result)): T?
+---@return Result # Result<T>
 function Result.try(fn)
     local thread = coroutine.create(fn)
     local step