sl0ppty: say what the config could not honour

A config that half-applied said nothing. An unknown shader, a binding
that does not parse, an include that is not there: the file loaded, that
line did not, and the session announced "config reloaded" as though
nothing had happened. Every one of those messages was already being
produced -- config_load has filled `err` on a successful load since it
was written -- and then dropped on the floor by every caller, because a
non-zero return meant "fine".

So the complaint from the last load is kept, and the front end says it
where it would have said "config reloaded". Once at startup too: a config
that loaded with a complaint still started the session, and the stderr
line goes where nobody attached can read it. The `reload` control verb
answers `{"ok":true,"warning":"..."}` -- ok, because the file did apply,
with the reason attached for a script that cares.

Two things fell out of writing the test for it.

An include's complaint was reported by nobody when the file in the middle
was fine. apply_includes only looked at the return value, so a theme that
loaded while *its* include was missing swallowed the message: the child
returned true, and true meant there was nothing to say. The complaint now
travels up whether or not the include itself loaded.

And a complaint now carries the name of the file it happened in, exactly
once -- added by the file that produced it, never by the files that
included it, because prefixing at every level builds a chain that
truncates before the part that matters. So:

    t.kdl: unknown shader: bloom
    keys.kdl: line 2: unknown action fly
    b.kdl: includes nested too deep (a cycle?)
    cannot open /home/you/.config/sl0ppty/themes/nope.kdl

which is enough to know which file to open, in a message that fits in a
toast.

1 files changed, 20 insertions, 1 deletions

diff --git a/tests/test_include.py b/tests/test_include.py
index 42baa89..b2f5200 100755
--- a/tests/test_include.py
+++ b/tests/test_include.py
@@ -123,7 +123,8 @@ def test_anything_can_be_included_not_only_a_theme():
 
 def test_a_missing_include_costs_a_line_and_no_more():
     """Losing your keybindings over a mistyped theme name would be a worse
-    answer than a session that carries on without the theme (D9)."""
+    answer than a session that carries on without the theme (D9) -- but silence
+    would be its own kind of wrong, so it is a line and not nothing."""
     root = tree({"config.kdl": 'include "themes/nope.kdl"\ngap 2\n'})
     with Session(SH, cols=60, rows=14, config=root + "/config.kdl") as s:
         s.settle()
@@ -131,6 +132,23 @@ def test_a_missing_include_costs_a_line_and_no_more():
         check("and the rest of the file applied anyway", s.pane()["x"] == 4,
               str(s.pane()))
 
+        reply = s.api("reload")
+        check("the reload succeeds", reply.get("ok"), str(reply))
+        check("...and says which line it could not honour",
+              "nope.kdl" in reply.get("warning", ""), str(reply))
+        check("the session says it out loud too",
+              "nope.kdl" in s.snapshot().screen(),
+              repr(s.snapshot().screen()[-200:]))
+
+
+def test_a_cycle_says_so():
+    root = tree({"a.kdl": 'include "b.kdl"\n', "b.kdl": 'include "a.kdl"\n'})
+    with Session(SH, cols=70, rows=14, config=root + "/a.kdl") as s:
+        s.settle()
+        reply = s.api("reload")
+        check("a cycle is reported rather than followed",
+              "too deep" in reply.get("warning", ""), str(reply))
+
 
 def test_a_cycle_stops_rather_than_spinning():
     """A config that includes itself is a mistake, and the depth limit is what
@@ -195,6 +213,7 @@ if __name__ == "__main__":
     test_a_leading_tilde_is_a_home_directory()
     test_anything_can_be_included_not_only_a_theme()
     test_a_missing_include_costs_a_line_and_no_more()
+    test_a_cycle_says_so()
     test_a_cycle_stops_rather_than_spinning()
     test_an_include_is_picked_up_by_a_reload()
     test_every_contrib_theme_can_be_included()