Fix julia#55850 by using safe_realpath instead of abspath in projname (#4025) (#4027)

Author: christiangnrd

src/REPLMode/REPLMode.jl

@@ -10,7 +10,7 @@ import REPL: TerminalMenus
 
 import ..casesensitive_isdir, ..OFFLINE_MODE, ..linewrap, ..pathrepr
 using ..Types, ..Operations, ..API, ..Registry, ..Resolve
-import ..stdout_f, ..stderr_f
+import ..stdout_f, ..stderr_f, ..safe_realpath
 
 const TEST_MODE = Ref{Bool}(false)
 const PRINTED_REPL_WARNING = Ref{Bool}(false)
@@ -497,7 +497,7 @@ function projname(project_file::String)
     end
     for depot in Base.DEPOT_PATH
         envdir = joinpath(depot, "environments")
-        if startswith(abspath(project_file), abspath(envdir))
+        if startswith(safe_realpath(project_file), safe_realpath(envdir))
             return "@" * name
         end
     end

test/repl.jl

@@ -726,4 +726,15 @@ end
     end
 end
 
+@testset "JuliaLang/julia #55850" begin
+    tmp_55850 = mktempdir()
+    tmp_sym_link = joinpath(tmp_55850, "sym")
+    symlink(tmp_55850, tmp_sym_link; dir_target=true)
+    # DEPOT_PATH must stay only the temp directory otherwise the bug is hidden
+    withenv("JULIA_DEPOT_PATH" => tmp_sym_link, "JULIA_LOAD_PATH" => nothing) do
+        prompt = readchomp(`$(Base.julia_cmd()[1]) --project=$(dirname(@__DIR__)) --startup-file=no -e "using Pkg: Pkg, REPLMode; Pkg.activate(io=devnull); print(REPLMode.promptf())"`)
+        @test prompt == "(@v$(VERSION.major).$(VERSION.minor)) pkg> "
+    end
+end
+
 end # module