ocamldep -sort returns success despite cyclic files warning

[vicuna]

Original bug ID: 7710
Reporter: baileyparker
Status: resolved (set by @xavierleroy on 2018-02-11T13:55:42Z)
Resolution: fixed
Priority: normal
Severity: minor
Version: 4.06.0
Target version: 4.07.0+dev/beta2/rc1/rc2
Fixed in version: 4.07.0+dev/beta2/rc1/rc2
Category: tools (ocaml{lex,yacc,dep,debug,...})
Monitored by: @nojb @dbuenzli

Bug description

If you try running ocamldep on mli files that cyclicly reference eachother, you receive a warning printed to stderr, but ocamldep still prints an ordering and returns 0.

Given that cyclically referencing files are illegal, it should at least return a non-zero status (and probably shouldn't print an order since it is impossible to order cyclically referential files). Currently, when used in a scripting context, you have to (fragilely) search stderr for "Warning: cycle in dependencies." to determine if the output list is actually valid (because if you just try to ocamlc -c *.mli in the returned order you will get an unhelped message that B is unbound--not that there were cyclic references).

Steps to reproduce

a.mli:
type bill = { a : int }
val foo : B.baz -> int

b.mli:
type bar = { a : int; b : int }
val baz : bar -> A.bill -> int

1. Place the above into files in the same directory
2. Run ocamldep -sort a.mli b.mli
3. Notice the "Warning: cycle in dependencies. End of list is not sorted."
4. Notice echo $? is 0

Additional information

Relevant code:

ocaml/driver/makedepend.ml

Lines 466 to 467 in 8daa184

	Format.fprintf Format.err_formatter
	"@[Warning: cycle in dependencies. End of list is not sorted.@]@.";

[vicuna]

Comment author: @xavierleroy

I agree with your analysis. Fix in progress at #1578

[vicuna]

Comment author: @xavierleroy

Fix merged in trunk.