Merge 77d274f into fbfe5d4

core/settings.lua

@@ -111,6 +111,10 @@ function settings:declare (spec)
   if spec.name then
     SU.deprecated("'name' argument of SILE.settings:declare", "'parameter' argument of SILE.settings:declare", "0.10.10", "0.11.0")
   end
+  if self.declarations[spec.parameter] then
+    SU.debug("settings", "Attempt to re-declare setting: " .. spec.parameter)
+    return
+  end
   self.declarations[spec.parameter] = spec
   self:set(spec.parameter, spec.default, true)
 end

tests/bidi.sil

@@ -37,4 +37,6 @@ One two אבג three four
 My hovercraft is full of eels.
 
 הרחפת שלי מלאה בצלופחים
+
+\set[parameter=typesetter.breakwidth]% restore default before folio is output (see #1708)
 \end{document}

tests/bug-1708.expected

@@ -0,0 +1,66 @@
+Set paper size 	209.7637818	297.6377985
+Begin page
+Mx 	17.4104
+My 	41.1471
+Set font 	Gentium Plus;10;400;;normal;;;LTR
+T	47 w=4.7607	(L)
+Mx 	27.1711
+T	82 w=5.0293	(o)
+Mx 	37.2004
+T	85 w=3.9600	(r)
+Mx 	46.1604
+T	72 w=4.6191	(e)
+Mx 	55.7795
+T	80 w=8.0322	(m)
+Mx 	66.4616
+T	76 w=2.7100	(i)
+Mx 	74.1715
+T	83 w=5.2979	(p)
+Mx 	84.4694
+T	86 w=3.8623	(s)
+Mx 	93.3317
+T	88 w=5.2979	(u)
+Mx 	103.6295
+T	80 w=8.0322	(m)
+Mx 	111.6618
+My 	37.9684
+Set font 	Gentium Plus;6.81152;400;;normal;;;LTR
+T	20 w=3.1962	(1)
+Mx 	17.4104
+My 	53.1471
+Set font 	Gentium Plus;10;400;;normal;;;LTR
+T	47 w=4.7607	(L)
+Mx 	27.1711
+T	82 w=5.0293	(o)
+Mx 	37.2004
+T	85 w=3.9600	(r)
+Mx 	46.1604
+T	72 w=4.6191	(e)
+Mx 	55.7795
+T	80 w=8.0322	(m)
+Mx 	66.4619
+T	76 w=2.7100	(i)
+Mx 	74.1719
+T	83 w=5.2979	(p)
+Mx 	84.4697
+T	86 w=3.8623	(s)
+Mx 	93.3320
+T	88 w=5.2979	(u)
+Mx 	103.6299
+T	80 w=8.0322	(m)
+Mx 	17.4104
+My 	247.7565
+Set font 	Gentium Plus;9;400;;normal;;;LTR
+T	20 w=4.2231	(1)
+Mx 	21.6335
+T	17 w=2.0610	(.)
+Mx 	41.6946
+T	87 w=3.0981	(t)
+Mx 	49.7927
+T	72 w=4.1572	(e)
+Mx 	58.9499
+T	86 w=3.4761	(s)
+Mx 	67.4260
+T	87 w=3.0981	(t)
+End page
+Finish

tests/bug-1708.sil

@@ -0,0 +1,12 @@
+\begin[papersize=a7,class=book]{document}
+\neverindent
+\nofolios
+\set[parameter=document.letterspaceglue, value=5pt]
+% Bug 1708: New typesetter instance (as e.g. done via a footnote)
+% shouldn't reset settings from the global scope.
+
+Lorem ipsum\footnote{test}
+
+Lorem ipsum% Should still have letterspacing at 5pt
+
+\end{document}

typesetters/base.lua

@@ -1,3 +1,11 @@
+--- SILE typesetter (default/base) class.
+--
+-- @copyright License: MIT
+-- @module typesetters.base
+--
+
+-- Typesetter base class
+
 local typesetter = pl.class()
 typesetter.type = "typesetter"
 typesetter._name = "base"
@@ -39,6 +47,27 @@ function typesetter:init (frame)
 end
 
 function typesetter:_init (frame)
+  self:declareSettings()
+  self.hooks = {}
+  self.breadcrumbs = SU.breadcrumbs()
+
+  self.frame = nil
+  self.stateQueue = {}
+  self:initFrame(frame)
+  self:initState()
+  -- In case people use stdlib prototype syntax off of the instantiated typesetter...
+  getmetatable(self).__call = self.init
+  return self
+end
+
+function typesetter:declareSettings()
+
+  -- Settings common to any typesetter instance.
+  -- These shouldn't be re-declared and overwritten/reset in the typesetter
+  -- constructor (see issue https://github.com/sile-typesetter/sile/issues/1708).
+  -- On the other hand, it's fairly acceptable to have them made global:
+  -- Any derived typesetter, whatever its implementation, should likely provide
+  -- some logic for them (= widows, orphans, spacing, etc.)
 
   SILE.settings:declare({
     parameter = "typesetter.widowpenalty",
@@ -103,16 +132,6 @@ function typesetter:_init (frame)
     help = "Width to break lines at"
   })
 
-  self.hooks = {}
-  self.breadcrumbs = SU.breadcrumbs()
-
-  self.frame = nil
-  self.stateQueue = {}
-  self:initFrame(frame)
-  self:initState()
-  -- In case people use stdlib prototype syntax off of the instantiated typesetter...
-  getmetatable(self).__call = self.init
-  return self
 end
 
 function typesetter:initState ()