inconsistent search path for compilecache (still looks in .)

[stevengj]

After #12695 and 75ab360, require no longer looks in the current directory. However, Base.compilecache uses include and so it still looks in the current directory.

This inconsistency needs to be fixed by 0.4, I think.

[JeffBezanson]

Actually I think the real problem is

julia/base/loading.jl

Line 331 in e0b4510

path = find_in_path(name)

compilecache uses include, but it passes it an absolute path. However it should pass nothing as the working directory to find_in_path the way require does.

[stevengj]

Right, that should do it.

[stevengj]

Note that recompiling a stale cache file still works even if the module is no longer in the path, because the cache file embeds the absolute path of the module it came from. This leads to the odd situation where using Foo works if Foo was ever in the path and was compiled, but ceases to work if the cache file is deleted.

This would be solved by making the LOAD_PATH part of the .ji file header, but I think it would be annoying to have to recompile all your packages whenever you change the load path. A nicer alternative: when loading Foo.ji, consider it stale if the stored path of Foo.jl does not match what find_in_path(Foo.jl) returns.

[stevengj]

(I should have a PR shortly.)