improve develop err message (#421)

* improve develop err message

* small changes

stdlib/Pkg/src/API.jl

@@ -25,6 +25,12 @@ add_or_develop(pkgs::Vector{PackageSpec}; kwargs...)       = add_or_develop(Cont
 
 function add_or_develop(ctx::Context, pkgs::Vector{PackageSpec}; mode::Symbol, kwargs...)
     Context!(ctx; kwargs...)
+
+    # if julia is passed as a package the solver gets tricked;
+    # this catches the error early on
+    any(pkg->(pkg.name == "julia"), pkgs) &&
+        cmderror("Trying to $mode julia as a package")
+
     ctx.preview && preview_info()
     if mode == :develop
         new_git = handle_repos_develop!(ctx, pkgs)
@@ -36,6 +42,10 @@ function add_or_develop(ctx::Context, pkgs::Vector{PackageSpec}; mode::Symbol, k
     registry_resolve!(ctx.env, pkgs)
     stdlib_resolve!(ctx, pkgs)
     ensure_resolved(ctx.env, pkgs, registry=true)
+
+    any(pkg -> Types.collides_with_project(ctx.env, pkg), pkgs) &&
+        cmderror("Cannot $mode package with the same name or uuid as the project")
+
     Operations.add_or_develop(ctx, pkgs; new_git=new_git)
     ctx.preview && preview_info()
     return

stdlib/Pkg/src/Operations.jl

@@ -1043,12 +1043,6 @@ function rm(ctx::Context, pkgs::Vector{PackageSpec})
 end
 
 function add_or_develop(ctx::Context, pkgs::Vector{PackageSpec}; new_git = UUID[])
-    # if julia is passed as a package the solver gets tricked;
-    # this catches the error early on
-    any(pkg->(pkg.uuid == uuid_julia), pkgs) &&
-        cmderror("Trying to add julia as a package")
-    any(pkg -> Types.collides_with_project(ctx.env, pkg), pkgs) &&
-        cmderror("Cannot add package with the same name or uuid as the project")
     # copy added name/UUIDs into project
     for pkg in pkgs
         ctx.env.project["deps"][pkg.name] = string(pkg.uuid)

stdlib/Pkg/src/REPLMode.jl

@@ -562,9 +562,10 @@ end
 
 function do_add_or_develop!(ctx::Context, tokens::Vector{Token}, cmd::CommandKind)
     @assert cmd in (CMD_ADD, CMD_DEVELOP)
+    mode = cmd == CMD_ADD ? :add : :develop
     # tokens: package names and/or uuids, optionally followed by version specs
     isempty(tokens) &&
-        cmderror("`add` – list packages to add")
+        cmderror("`$mode` – list packages to $mode")
     pkgs = PackageSpec[]
     prev_token_was_package = false
     while !isempty(tokens)
@@ -589,11 +590,11 @@ function do_add_or_develop!(ctx::Context, tokens::Vector{Token}, cmd::CommandKin
                 pkgs[end].repo.rev = token.rev
             end
         elseif token isa Option
-            cmderror("`add` doesn't take options: $token")
+            cmderror("`$mode` doesn't take options: $token")
         end
         prev_token_was_package = parsed_package
     end
-    return API.add_or_develop(ctx, pkgs, mode=(cmd == CMD_ADD ? :add : :develop))
+    return API.add_or_develop(ctx, pkgs, mode=mode)
 end
 
 function do_up!(ctx::Context, tokens::Vector{Token})