From 3dd12d13f81ec5920e6d23248933a11c54ddb590 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Thu, 14 Sep 2023 13:36:39 +0200
Subject: [PATCH] Fix invisibles on final page (#2141)

---
 crates/typst-library/src/layout/mod.rs    |  16 ++++++++++------
 crates/typst-library/src/shared/behave.rs |   9 +++++----
 tests/ref/bugs/pagebreak-bibliography.png | Bin 0 -> 1860 bytes
 tests/typ/bugs/pagebreak-bibliography.typ |   5 +++++
 4 files changed, 20 insertions(+), 10 deletions(-)
 create mode 100644 tests/ref/bugs/pagebreak-bibliography.png
 create mode 100644 tests/typ/bugs/pagebreak-bibliography.typ

diff --git a/crates/typst-library/src/layout/mod.rs b/crates/typst-library/src/layout/mod.rs
index d9e8ec9aa..018cf1a69 100644
--- a/crates/typst-library/src/layout/mod.rs
+++ b/crates/typst-library/src/layout/mod.rs
@@ -250,7 +250,7 @@ fn realize_root<'a>(
 
     let mut builder = Builder::new(vt, scratch, true);
     builder.accept(content, styles)?;
-    builder.interrupt_page(Some(styles))?;
+    builder.interrupt_page(Some(styles), true)?;
     let (pages, shared) = builder.doc.unwrap().pages.finish();
     Ok((DocumentElem::new(pages.to_vec()).pack(), shared))
 }
@@ -375,7 +375,7 @@ impl<'a, 'v, 't> Builder<'a, 'v, 't> {
             .to::<PagebreakElem>()
             .map_or(false, |pagebreak| !pagebreak.weak(styles));
 
-        self.interrupt_page(keep.then_some(styles))?;
+        self.interrupt_page(keep.then_some(styles), false)?;
 
         if let Some(doc) = &mut self.doc {
             if doc.accept(content, styles) {
@@ -424,7 +424,7 @@ impl<'a, 'v, 't> Builder<'a, 'v, 't> {
             if self.doc.is_none() {
                 bail!(span, "page configuration is not allowed inside of containers");
             }
-            self.interrupt_page(outer)?;
+            self.interrupt_page(outer, false)?;
         } else if local.interruption::<ParElem>().is_some()
             || local.interruption::<AlignElem>().is_some()
         {
@@ -462,10 +462,14 @@ impl<'a, 'v, 't> Builder<'a, 'v, 't> {
         Ok(())
     }
 
-    fn interrupt_page(&mut self, styles: Option<StyleChain<'a>>) -> SourceResult<()> {
+    fn interrupt_page(
+        &mut self,
+        styles: Option<StyleChain<'a>>,
+        last: bool,
+    ) -> SourceResult<()> {
         self.interrupt_par()?;
         let Some(doc) = &mut self.doc else { return Ok(()) };
-        if !self.flow.0.is_basically_empty() || (doc.keep_next && styles.is_some()) {
+        if (doc.keep_next && styles.is_some()) || self.flow.0.has_strong_elements(last) {
             let (flow, shared) = mem::take(&mut self.flow).0.finish();
             let styles = if shared == StyleChain::default() {
                 styles.unwrap_or_default()
@@ -588,7 +592,7 @@ struct ParBuilder<'a>(BehavedBuilder<'a>);
 impl<'a> ParBuilder<'a> {
     fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) -> bool {
         if content.is::<MetaElem>() {
-            if !self.0.is_basically_empty() {
+            if self.0.has_strong_elements(false) {
                 self.0.push(content.clone(), styles);
                 return true;
             }
diff --git a/crates/typst-library/src/shared/behave.rs b/crates/typst-library/src/shared/behave.rs
index 471daa189..ed7a2593b 100644
--- a/crates/typst-library/src/shared/behave.rs
+++ b/crates/typst-library/src/shared/behave.rs
@@ -32,10 +32,11 @@ impl<'a> BehavedBuilder<'a> {
 
     /// Whether the builder is empty except for some weak elements that will
     /// probably collapse.
-    pub fn is_basically_empty(&self) -> bool {
-        self.builder.is_empty()
-            && self.staged.iter().all(|(_, behaviour, _)| {
-                matches!(behaviour, Behaviour::Weak(_) | Behaviour::Invisible)
+    pub fn has_strong_elements(&self, last: bool) -> bool {
+        !self.builder.is_empty()
+            || self.staged.iter().any(|(_, behaviour, _)| {
+                !matches!(behaviour, Behaviour::Weak(_) | Behaviour::Invisible)
+                    || (last && *behaviour == Behaviour::Invisible)
             })
     }
 
diff --git a/tests/ref/bugs/pagebreak-bibliography.png b/tests/ref/bugs/pagebreak-bibliography.png
new file mode 100644
index 0000000000000000000000000000000000000000..43de1574465eb89a6e02c2e75f1e444986c60f05
GIT binary patch
literal 1860
zcmV-K2fO%*P)<h;3K|Lk000e1NJLTq009I5002%100000<JUK6000LINkl<Zc-rmP
zeUQ~v9mny{eD2=Ma$y5kAP}$`aT%~A6eYwEdr&cOu%^a<a709uF?DCm%!l%c)JQ=M
zGBtJ33PvRe@u}iLVF4M`MhaX3<zd-f_DNV4?moTy<9F|Jt#vgAm$uI5uXE2izu!Ig
zb?@(c&Xqz!LPA19LPA19K4$noOF#$+0U;m+gn$qb0zyCt2mv7=1cZPP5CTF#IC=;N
zS3j7_eqFnK?x(fl;`!^38bW<teKXDVb+y@@P0z0aW)JESlPX$zZyuO$C8G9*#fOgI
zYImN}KUcc_s3F{#NDn6ZoqosebmtY)qfqw8KDH0*>{^f~bpv3L^}Qpw+NPq5B+WW{
zk3-!>lH$vXpBra)dLimNK^hM*K~nZNK3d8L;7Td4=}4}3m8986u_mmxJq$<<vAga8
z;7&yx(<Eirgt5}G(KWfc{)n!3<55O<Tha)CLP-mwzAa_6hA=LJK<V53Pa(XMLHLEF
zdp<Dq;Rqj*UGpw|reh*ZmRuC|9oVqqFv33;Z*KTkgvKpP(tT`x@!7ZPTkcl5YQf^-
zU-sx{zX_z)Y=n}RqT&6oJ-xO%Gp}~_I@rBvW8DW34lQ4{8{qvNC8Z@hw$;Fa?Ym2N
zm3{gMwnqT#yW5ul%pTo8rv4d(P3K7JyEGeN`S}AoNt*z8{3Lz0i{g``o%G=4osS!4
zC%5h!aYDuNsUvbVjHi+w)Bx{Zk~}e?&bKrGYbFiO@xbQWa;2`bnpzO{-_lcx-vK<D
zl%(WbSlUDSq&v}ni14|)e>y(Ti61ortePsRAcN5DoC~_zel81P+iiK0wgFr%T}R#J
zQqQ%(p>H~`f_v?Y0g5KYr2a4DNZ!ucq-V3WxBYWq{iL{*JnPIKo+zm>gK%EoFAeXM
z{x$CXyri`N4SnKIHMh&-kU#cYLz2olZ&B3MTN(l|&GvREirWRL?8jlUq&>hgDK7<$
zL+yftFyH<<)Y)DKz$hs(^6|ks8>ZOzL!q75kml4gP&Gh`zmY~5{u;a_X$HU(lI{Z7
z9GlsWHKBHfq$!O6CrQIH2q|E^?G@Pw*Gj4c2HRr*?z4RdTxwqk^s=La&-W$0PW|6f
zu&~?7JK+&Y#Q@VK9RMCof9RIN*h?A<(9lon-vCVSQP-Y@kuj2f-5SD7+w-y!3L}I)
zwx<AWu{{Q^v_}Gc?FRsuD8({oswRNnOZp4ZX-fxyt&&D&BNRwy05DV1Q&7?6=62m3
zcuvxnTSIu*_RLlgR@lB4V889Yu+r|8B9-g-rVK*P;Wyg*;OMxdKW8J<Svsy&go>mz
z3~ujS*1ibElDf2pFvs?iRuGoho(w?J&Ihis3#(??>ElK=!kgbtob`v_Nm`zb&=`|O
zwTi%HwpXV5Ol#kB0&ht=zBPoO*?zATgm-P92|&Ug0yGWn6LbFAf92m09*cQ8ES2<1
zHo{IxSG11smhJJ6#WuGKLU9YiZzO#OV6b#*=F3O{-;D|$=S#=56vhgmw;eABDs2A*
zxY*kp_8q?UgcgK`q`eN7+I}?~;c3Y)0vjaV2QWYyp1%4UcFq^Zw$F*NNYZHlWd%~_
z4FJbW0|6#P2&rS7zXxDMrqE55v>kZX_HDp?yZa899c>~l87C>K?eE%N2*0(x7~o3V
z2Y~aW$p9})x)q>j`iKJj$+ll;7lejOB_)c=*FW4}N<InjdXALX0$gBwPV=Fu?)fsn
zrd&z$f$G7M<^kMbCl)ooH^5z<2PWDcaO&u>6K`5j3zYV;{cQ9$J*7d9%qWo5_baoa
zU&2Gw{#Y7S1vE~PG^zoLEXC4i_vQk7Ank#0d$*S1PN!YB1K^96q}b{3wUg%@@9uf=
zb9Vs@ib;}tzH?1nlH6k(ux7Y*Y&>V;PJos9&ZPGiCgen|{Q%3lNypsVI7-U7sxCrE
z_DZ<lLjX^7l_Yg9y*s+3U-ZA^>C9I9X(Q|_DXXlht|;AIav;-HR$f(8Q&nCLuWY4p
z>+%)pk<#+2nwqM;B~3M@l~DtL+6~J#XZ}D<8#wNap#`07`>RxzRo2v0m6t?A2RFW0
z3-v2ssm;`c>NT%cMPqe)DyrYF-dn={(#o2es`5SQ+nw^6eeHs9B-1=8+8djTZ?JRQ
zJn&~~LYpbgy^0Qp@PPerx_QD!Jk1{q;d*cGcnH(&>!Mb5%#XD>b*k;^HfQ{O$=uv?
z>39ggvh&^mXu2?QciU6Xx4o&Y2~XILt?qyb^=H|+Ke+S8DFv6j(dNVzg`I4VoO|%Y
zr`&JH?xF)C!0MYW8$adNCu=@p+T0me7ZzS~)%3j|J|*?YoY(1?2>)FP2mv7=1cZPP
y5CTF#2nYcoAOwU@j1UqM5)u*;5)u;9O8yBr)Q->ir1vub0000<MNUMnLSTa8{E@-{

literal 0
HcmV?d00001

diff --git a/tests/typ/bugs/pagebreak-bibliography.typ b/tests/typ/bugs/pagebreak-bibliography.typ
new file mode 100644
index 000000000..bfc782501
--- /dev/null
+++ b/tests/typ/bugs/pagebreak-bibliography.typ
@@ -0,0 +1,5 @@
+// Test weak pagebreak before bibliography.
+
+---
+#pagebreak(weak: true)
+#bibliography("/files/works.bib")