fix(github): use evaluated out_file as asset file value (#1208)

This makes it so that after parsing the source, the `{{source.asset.file}}` context value points to the downloaded file,
rather than the raw value. This is helpful for source definitions such as:

```yaml
source:
  id: pkg:github/mrjosh/helm-ls@v0.0.3
  asset:
    - target: win_x64
      file: helm_ls_windows_amd64:helm_ls_windows_amd64.exe
    # …

bin:
  # This now evaluates to "helm_ls_windows_amd64.exe" rather than "helm_ls_windows_amd64:helm_ls_windows_amd64.exe".
  helm_ls: "{{source.asset.file}}"
```

2 files changed, 101 insertions, 15 deletions

diff --git a/lua/mason-core/installer/registry/providers/github.lua b/lua/mason-core/installer/registry/providers/github.lua
index 06ac0b06..243f021d 100644
--- a/lua/mason-core/installer/registry/providers/github.lua
+++ b/lua/mason-core/installer/registry/providers/github.lua
@@ -68,27 +68,51 @@ local release = {
             ---@type { out_file: string, download_url: string }[]
             local downloads = {}
 
-            for __, file in ipairs(type(asset.file) == "string" and { asset.file } or asset.file) do
-                local asset_file_components = _.split(":", file)
-                local source_file = try(expr.interpolate(_.head(asset_file_components), expr_ctx))
-                local out_file = try(expr.interpolate(_.last(asset_file_components), expr_ctx))
+            local interpolated_asset = try(expr.tbl_interpolate(asset, expr_ctx))
 
-                if _.matches("/$", out_file) then
-                    -- out_file is a dir expression (e.g. "libexec/")
-                    out_file = out_file .. source_file
-                end
+            ---@param file string
+            ---@return Result # Result<{ source_file: string, out_file: string }>
+            local function parse_asset_file(file)
+                return Result.try(function(try)
+                    local asset_file_components = _.split(":", file)
+                    local source_file = try(expr.interpolate(_.head(asset_file_components), expr_ctx))
+                    local out_file = try(expr.interpolate(_.last(asset_file_components), expr_ctx))
+
+                    if _.matches("/$", out_file) then
+                        -- out_file is a dir expression (e.g. "libexec/")
+                        out_file = out_file .. source_file
+                    end
+
+                    return {
+                        source_file = source_file,
+                        out_file = out_file,
+                    }
+                end)
+            end
 
-                table.insert(downloads, {
-                    out_file = out_file,
+            local get_downloads = _.map(function(asset_file)
+                return {
+                    out_file = asset_file.out_file,
                     download_url = settings.current.github.download_url_template:format(
                         ("%s/%s"):format(purl.namespace, purl.name),
                         purl.version,
-                        source_file
+                        asset_file.source_file
                     ),
-                })
-            end
+                }
+            end)
 
-            local interpolated_asset = try(expr.tbl_interpolate(asset, expr_ctx))
+            if type(asset.file) == "string" then
+                local parsed_asset_file = try(parse_asset_file(asset.file))
+                downloads = get_downloads { parsed_asset_file }
+                interpolated_asset.file = parsed_asset_file.out_file
+            else
+                local parsed_asset_files = {}
+                for _, file in ipairs(asset.file) do
+                    table.insert(parsed_asset_files, try(parse_asset_file(file)))
+                end
+                downloads = get_downloads(parsed_asset_files)
+                interpolated_asset.file = _.map(_.prop "out_file", parsed_asset_files)
+            end
 
             ---@class ParsedGitHubReleaseSource : ParsedPackageSource
             local parsed_source = {
diff --git a/tests/mason-core/installer/registry/providers/github_spec.lua b/tests/mason-core/installer/registry/providers/github_spec.lua
index de301d88..c70e0b10 100644
--- a/tests/mason-core/installer/registry/providers/github_spec.lua
+++ b/tests/mason-core/installer/registry/providers/github_spec.lua
@@ -75,7 +75,7 @@ describe("github provider :: parsing", function()
             Result.success {
                 repo = "namespace/name",
                 asset = {
-                    file = "file-linux-amd64-2023-03-09.tar.gz:out-dir/",
+                    file = "out-dir/file-linux-amd64-2023-03-09.tar.gz",
                 },
                 downloads = {
                     {
@@ -92,6 +92,68 @@ describe("github provider :: parsing", function()
         )
     end)
 
+    it("should expand returned asset.file to point to out_file", function()
+        assert.same(
+            Result.success {
+                repo = "namespace/name",
+                asset = {
+                    file = {
+                        "out-dir/linux-amd64-2023-03-09.tar.gz",
+                        "LICENSE.txt",
+                        "README.md",
+                    },
+                },
+                downloads = {
+                    {
+                        out_file = "out-dir/linux-amd64-2023-03-09.tar.gz",
+                        download_url = "https://github.com/namespace/name/releases/download/2023-03-09/linux-amd64-2023-03-09.tar.gz",
+                    },
+                    {
+                        out_file = "LICENSE.txt",
+                        download_url = "https://github.com/namespace/name/releases/download/2023-03-09/license",
+                    },
+                    {
+                        out_file = "README.md",
+                        download_url = "https://github.com/namespace/name/releases/download/2023-03-09/README.md",
+                    },
+                },
+            },
+            github.parse({
+                asset = {
+                    file = {
+                        "linux-amd64-{{version}}.tar.gz:out-dir/",
+                        "license:LICENSE.txt",
+                        "README.md",
+                    },
+                },
+            }, purl(), { target = "linux_x64" })
+        )
+    end)
+
+    it("should interpolate asset table", function()
+        assert.same(
+            Result.success {
+                repo = "namespace/name",
+                asset = {
+                    file = "linux-amd64-2023-03-09.tar.gz",
+                    bin = "linux-amd64-2023-03-09",
+                },
+                downloads = {
+                    {
+                        out_file = "linux-amd64-2023-03-09.tar.gz",
+                        download_url = "https://github.com/namespace/name/releases/download/2023-03-09/linux-amd64-2023-03-09.tar.gz",
+                    },
+                },
+            },
+            github.parse({
+                asset = {
+                    file = "linux-amd64-{{version}}.tar.gz",
+                    bin = "linux-amd64-{{version}}",
+                },
+            }, purl(), { target = "linux_x64" })
+        )
+    end)
+
     it("should parse build source", function()
         assert.same(
             Result.success {