remove ability to give a git revision to devved packages (#581)

* remove ability to give a git revision to devved packages

* wip

stdlib/Pkg/docs/src/index.md

@@ -347,13 +347,13 @@ If we try to `dev` a package at some branch that already exists at `~/.julia/dev
 For example:
 
 ```
-(v0.7) pkg> dev Example#master
+(v0.7) pkg> dev Example
   Updating git-repo `https://github.com/JuliaLang/Example.jl.git`
 [ Info: Path `/Users/kristoffer/.julia/dev/Example` exists and looks like the correct package, using existing path instead of cloning
 ```
 
-Note the info message saying that it is using the existing path. This means that you cannot use `dev` to e.g. change branches of
-an already developed package.
+Note the info message saying that it is using the existing path. As a general rule, the package manager will
+never touch files that are tracking a path.
 
 If `dev` is used on a local path, that path to that package is recorded and used when loading that package.
 The path will be recorded relative to the project file, unless it is given as an absolute path.

stdlib/Pkg/src/API.jl

@@ -33,7 +33,12 @@ function add_or_develop(ctx::Context, pkgs::Vector{PackageSpec}; mode::Symbol, s
 
     # All developed packages should go through handle_repos_develop so just give them an empty repo
     for pkg in pkgs
-        mode == :develop && pkg.repo == nothing && (pkg.repo = Types.GitRepo())
+        if mode == :develop
+            pkg.repo == nothing && (pkg.repo = Types.GitRepo())
+            if !isempty(pkg.repo.rev)
+                pkgerror("git revision cannot be given to `develop`")
+            end
+        end
     end
 
     # if julia is passed as a package the solver gets tricked;

stdlib/Pkg/src/REPLMode.jl

@@ -397,6 +397,9 @@ function package_args(args::Vector{Token}, spec::CommandSpec)::Vector{PackageSpe
         elseif arg isa VersionRange
             pkgs[end].version = arg
         elseif arg isa Rev
+            if spec.kind == CMD_DEVELOP
+                pkgerror("a git revision cannot be given to `develop`")
+            end
             pkg = pkgs[end]
             if pkg.repo == nothing
                 pkg.repo = Types.GitRepo("", arg.rev)
@@ -1025,7 +1028,7 @@ pkg> add Example=7876af07-990d-54b4-ab0e-23690620f79a
         ("shared", OPT_SWITCH, :shared => true),
     ],
     md"""
-    develop [--shared|--local] pkg[=uuid] [#rev] ...
+    develop [--shared|--local] pkg[=uuid] ...
 
 Make a package available for development. If `pkg` is an existing local path that path will be recorded in
 the manifest and used. Otherwise, a full git clone of `pkg` at rev `rev` is made. The location of the clone is

stdlib/Pkg/src/Types.jl

@@ -545,13 +545,10 @@ function handle_repos_develop!(ctx::Context, pkgs::AbstractVector{PackageSpec},
                 project_path = mktempdir()
                 cp(repo_path, project_path; force=true)
                 LibGit2.with(LibGit2.GitRepo(project_path)) do repo
-                    rev = pkg.repo.rev
-                    if isempty(rev)
-                        if LibGit2.isattached(repo)
-                            rev = LibGit2.branch(repo)
-                        else
-                            rev = string(LibGit2.GitHash(LibGit2.head(repo)))
-                        end
+                    if LibGit2.isattached(repo)
+                        rev = LibGit2.branch(repo)
+                    else
+                        rev = string(LibGit2.GitHash(LibGit2.head(repo)))
                     end
                     gitobject, isbranch = get_object_branch(repo, rev)
                     try

stdlib/Pkg/test/pkg.jl

@@ -181,6 +181,7 @@ temp_pkg_dir() do project_path
         Pkg.rm(TEST_PKG.name)
         mktempdir() do devdir
             withenv("JULIA_PKG_DEVDIR" => devdir) do
+                @test_throws PkgError Pkg.develop(PackageSpec(url="bleh", rev="blurg"))
                 Pkg.develop(TEST_PKG.name)
                 @test isinstalled(TEST_PKG)
                 @test Pkg.API.__installed()[TEST_PKG.name] > old_v

stdlib/Pkg/test/repl.jl

@@ -42,16 +42,7 @@ temp_pkg_dir() do project_path
             Pkg.test("PackageWithBuildSpecificTestDeps")
         end
 
-        pkg"dev Example"
-        devdir = joinpath(DEPOT_PATH[1], "dev", "Example")
-        @test isdir(devdir)
-        rm(devdir; recursive=true)
-        @test !isdir(devdir)
-        pkg"dev Example#DO_NOT_REMOVE"
-        @test isdir(devdir)
-        LibGit2.with(LibGit2.GitRepo(devdir)) do repo
-            @test LibGit2.branch(repo) == "DO_NOT_REMOVE"
-        end
+        @test_throws PkgError pkg"dev Example#blergh"
 
         pkg"generate Foo"
         pkg"dev Foo"
@@ -211,10 +202,6 @@ temp_pkg_dir() do project_path; cd(project_path) do
                     @test Pkg.API.__installed()["UnregisteredWithoutProject"] == v"0.0.0"
                     Pkg.test("UnregisteredWithoutProject")
                     Pkg.test("UnregisteredWithProject")
-
-                    pkg"develop Example#c37b675"
-                    @test Base.find_package("Example") ==  joinpath(tmp, "Example", "src", "Example.jl")
-                    Pkg.test("Example")
                 end
             finally
                 empty!(DEPOT_PATH)