Add missing exec paths to new Zstd_jll stdlib (#59198)

`Zstd_jll.zstd_path::String` is provided by the non-stdlib JLL, like for
all executable products, so not having this is breaking, I believe.

Also add a test to catch this for existing/new stdlibs.

Author: IanButterworth

stdlib/Zstd_jll/src/Zstd_jll.jl

@@ -18,6 +18,8 @@ const LIBPATH_list = String[]
 artifact_dir::String = ""
 
 libzstd_path::String = ""
+zstd_path::String = ""
+zstdmt_path::String = ""
 const libzstd = LazyLibrary(
     if Sys.iswindows()
         BundledLazyLibraryPath("libzstd-1.dll")
@@ -79,8 +81,8 @@ function zstdmt(f::Function; adjust_PATH::Bool = true, adjust_LIBPATH::Bool = tr
         f(zstdmt())
     end
 end
-zstd() = adjust_ENV(`$(joinpath(Sys.BINDIR, Base.PRIVATE_LIBEXECDIR, zstd_exe))`)
-zstdmt() = adjust_ENV(`$(joinpath(Sys.BINDIR, Base.PRIVATE_LIBEXECDIR, zstdmt_exe))`)
+zstd() = adjust_ENV(`$zstd_path`)
+zstdmt() = adjust_ENV(`$zstdmt_path`)
 
 # Function to eagerly dlopen our library and thus resolve all dependencies
 function eager_mode()
@@ -94,6 +96,8 @@ is_available() = true
 
 function __init__()
     global libzstd_path = string(libzstd.path)
+    global zstd_path = joinpath(Sys.BINDIR, Base.PRIVATE_LIBEXECDIR, zstd_exe)
+    global zstdmt_path = joinpath(Sys.BINDIR, Base.PRIVATE_LIBEXECDIR, zstdmt_exe)
     global artifact_dir = dirname(Sys.BINDIR)
 end
 

test/stdlib_dependencies.jl

@@ -273,6 +273,47 @@ try
         end
     end
 
+    # Check that any JLL stdlib that defines executables also provides corresponding *_path variables
+    @testset "Stdlib JLL executable path variables" begin
+        for (_, (stdlib_name, _)) in Pkg.Types.stdlibs()
+            if !endswith(stdlib_name, "_jll")
+                continue
+            end
+
+            # Import the stdlib, skip it if it's not available on this platform
+            m = eval(Meta.parse("import $(stdlib_name); $(stdlib_name)"))
+            if !Base.invokelatest(getproperty(m, :is_available))
+                continue
+            end
+
+            # Look for *_exe constants that indicate executable definitions
+            exe_constants = Symbol[]
+            for name in names(m, all=true)
+                name_str = string(name)
+                if endswith(name_str, "_exe") && isdefined(m, name)
+                    push!(exe_constants, name)
+                end
+            end
+
+            # For each *_exe constant, check if there's a corresponding *_path variable
+            for exe_const in exe_constants
+                exe_name_str = string(exe_const)
+                # Convert from *_exe to *_path (e.g., zstd_exe -> zstd_path)
+                expected_path_var = Symbol(replace(exe_name_str, "_exe" => "_path"))
+
+                @test isdefined(m, expected_path_var)
+
+                if !isdefined(m, expected_path_var)
+                    @warn("Missing path variable",
+                        jll = stdlib_name,
+                        exe_constant = exe_const,
+                        expected_path_var = expected_path_var
+                    )
+                end
+            end
+        end
+    end
+
 finally
     if prev_env !== nothing
         Pkg.activate(prev_env)