feat(expr): use same context for value & filter evaluation (#778)

1 files changed, 34 insertions, 4 deletions

diff --git a/lua/mason-core/installer/registry/expr.lua b/lua/mason-core/installer/registry/expr.lua
index be704156..2713fcc4 100644
--- a/lua/mason-core/installer/registry/expr.lua
+++ b/lua/mason-core/installer/registry/expr.lua
@@ -1,5 +1,4 @@
 local _ = require "mason-core.functional"
-local string_funs = require "mason-core.functional.string"
 local Result = require "mason-core.result"
 
 local M = {}
@@ -14,14 +13,45 @@ local parse_expr = _.compose(
     _.split "|"
 )
 
+local FILTERS = {
+    format = _.format,
+    gsub = _.gsub,
+    to_lower = _.to_lower,
+    to_upper = _.to_upper,
+    trim = _.trim,
+    trim_start = _.trim_start,
+    tostring = tostring,
+}
+
+---@generic T : table
+---@param tbl T
+---@return T
+local function shallow_clone(tbl)
+    local res = {}
+    for k, v in pairs(tbl) do
+        res[k] = v
+    end
+    return res
+end
+
 ---@param str string
 ---@param ctx table<string, any>
 function M.eval(str, ctx)
+    ctx = shallow_clone(ctx)
     return Result.pcall(function()
+        setmetatable(ctx, { __index = FILTERS })
         return _.gsub("{{([^}]+)}}", function(expr)
             local components = parse_expr(expr)
-            local value =
-                assert(ctx[components.value_expr], ("Unable to interpolate value: %q."):format(components.value_expr))
+            local value = assert(
+                setfenv(
+                    assert(
+                        loadstring("return " .. components.value_expr),
+                        ("Failed to parse value :%q."):format(components.value_expr)
+                    ),
+                    ctx
+                )(),
+                ("Value is nil: %q."):format(components.value_expr)
+            )
             return _.reduce(
                 _.apply_to,
                 value,
@@ -31,7 +61,7 @@ function M.eval(str, ctx)
                             loadstring("return " .. filter_expr),
                             ("Failed to parse filter: %q."):format(filter_expr)
                         ),
-                        string_funs
+                        ctx
                     )()
                     assert(type(filter) == "function", ("Invalid filter expression: %q."):format(filter_expr))
                     return filter