Make sure repo.url points to a git repo before adding (#451)

* Check that repo urls point to a git repo

* Move `validate_repo_url` to `GitTools` module

* Add Pkg-specific error messages to GitTools `clone` and `fetch`

* Alter a test to be Windows-compatible

(cherry picked from commit 046bde4d660715291f6a84eaba3cd08917dc7cee)

stdlib/Pkg/src/GitTools.jl

@@ -95,7 +95,12 @@ function clone(url, source_path; header=nothing, kwargs...)
     catch err
         rm(source_path; force=true, recursive=true)
         err isa LibGit2.GitError || rethrow(err)
-        Pkg.Types.cmderror("failed to clone from $(url), error: $err")
+        if (err.class == LibGit2.Error.Net && err.code == LibGit2.Error.EINVALIDSPEC) ||
+           (err.class == LibGit2.Error.Repository && err.code == LibGit2.Error.ENOTFOUND)
+            Pkg.Types.cmderror("Git repository not found at '$(url)'")
+        else
+            Pkg.Types.cmderror("failed to clone from $(url), error: $err")
+        end
     finally
         print(stdout, "\033[2K") # clear line
         print(stdout, "\e[?25h") # put back cursor
@@ -122,7 +127,11 @@ function fetch(repo::LibGit2.GitRepo, remoteurl=nothing; header=nothing, kwargs.
         return LibGit2.fetch(repo; remoteurl=remoteurl, callbacks=callbacks, kwargs...)
     catch err
         err isa LibGit2.GitError || rethrow(err)
-        Pkg.Types.cmderror("failed to fetch from $(remoteurl), error: $err")
+        if (err.class == LibGit2.Error.Repository && err.code == LibGit2.Error.ERROR)
+            Pkg.Types.cmderror("Git repository not found at '$(remoteurl)'")
+        else
+            Pkg.Types.cmderror("failed to fetch from $(remoteurl), error: $err")
+        end
     finally
         print(stdout, "\033[2K") # clear line
         print(stdout, "\e[?25h") # put back cursor

stdlib/Pkg/test/pkg.jl

@@ -371,6 +371,44 @@ temp_pkg_dir() do project_path
     end # @testset
 end
 
+temp_pkg_dir() do project_path
+    @testset "invalid repo url" begin
+        cd(project_path) do
+            @test_throws CommandError Pkg.add("https://github.com")
+            Pkg.generate("FooBar")
+            @test_throws CommandError Pkg.add("./Foobar")
+        end
+    end
+end
+
+temp_pkg_dir() do project_path
+    function with_dummy_env(f)
+        TEST_SIG = LibGit2.Signature("TEST", "[email protected]", round(time()), 0)
+        env_path = joinpath(mktempdir(), "Dummy")
+        Pkg.generate(env_path)
+        repo = LibGit2.init(env_path)
+        LibGit2.add!(repo, "*")
+        LibGit2.commit(repo, "initial commit"; author=TEST_SIG, committer=TEST_SIG)
+        Pkg.activate(env_path)
+        try
+            f()
+        finally
+            Pkg.activate()
+        end
+    end
+    # pkg assumes `Example.jl` is still a git repo, it will try to fetch on `update`
+    # `fetch` should warn that it is no longer a git repo
+    with_dummy_env() do
+        @testset "inconsistent repo state" begin
+            package_path = joinpath(project_path, "Example")
+            LibGit2.clone("https://github.com/JuliaLang/Example.jl", package_path)
+            Pkg.add(package_path)
+            rm(joinpath(package_path, ".git"); force=true, recursive=true)
+            @test_throws CommandError Pkg.up()
+        end
+    end
+end
+
 include("repl.jl")
 
 end # module