From ada30cd5b14d97ac5b0bc4893b5bce797b53a3e9 Mon Sep 17 00:00:00 2001
From: wznmickey <first@wznmickey.com>
Date: Tue, 5 Nov 2024 03:27:25 -0500
Subject: [PATCH] Fix unstoppable empty footnote loop (#5354) (#5364)

---
 crates/typst-layout/src/flow/compose.rs          |   5 ++++-
 ...e-5354-footnote-empty-frame-infinite-loop.png | Bin 0 -> 2342 bytes
 tests/suite/layout/flow/footnote.typ             |   5 +++++
 3 files changed, 9 insertions(+), 1 deletion(-)
 create mode 100644 tests/ref/issue-5354-footnote-empty-frame-infinite-loop.png

diff --git a/crates/typst-layout/src/flow/compose.rs b/crates/typst-layout/src/flow/compose.rs
index 932ccc9ad..d49c3fc32 100644
--- a/crates/typst-layout/src/flow/compose.rs
+++ b/crates/typst-layout/src/flow/compose.rs
@@ -431,6 +431,9 @@ impl<'a, 'b> Composer<'a, 'b, '_, '_> {
         // Find nested footnotes in the entry.
         let nested = find_in_frames::<FootnoteElem>(&frames);
 
+        // Check if there are any non-empty frames.
+        let exist_non_empty_frame = frames.iter().any(|f| !f.is_empty());
+
         // Extract the first frame.
         let mut iter = frames.into_iter();
         let first = iter.next().unwrap();
@@ -440,7 +443,7 @@ impl<'a, 'b> Composer<'a, 'b, '_, '_> {
         // possible, we then migrate the origin frame to the next region to
         // uphold the footnote invariant (that marker and entry are on the same
         // page). If not, we just queue the footnote for the next page.
-        if first.is_empty() {
+        if first.is_empty() && exist_non_empty_frame {
             if migratable {
                 return Err(Stop::Finish(false));
             } else {
diff --git a/tests/ref/issue-5354-footnote-empty-frame-infinite-loop.png b/tests/ref/issue-5354-footnote-empty-frame-infinite-loop.png
new file mode 100644
index 0000000000000000000000000000000000000000..acad56b68b409512e542508268fc805d32bbcc31
GIT binary patch
literal 2342
zcmb7`eNYo;9>-&?2DKVJNAZ;?deYWv&a)LgAUPEqIquBaJ13_oIR{VX4mF^2Br(ax
zm$9j$7h6=sD7lsv?@BQp9SN3Y7t}yBKy;`^8cZNBL|!DD7m{qUFSoni_(!L6GdHt4
zyR);;+voTFexK*`@3#r3PhBvT#bQm*+nW0k^^{ZhyD5|Dw{*j57AxgtUhc*}$|t;R
zo%qk?J1?~dN!i#rOXu~&`9(JlIvW3b{q=0krQaB9ez`V%3@tbP?P#4gtK^BOv1<n@
zUg{Y9nyf#6@W>N#ho$k(F!}C2$L?{>oSO%4B;cvN>%_R^)B$}xVchikcRwQ5jEjHU
zbAKgxcO}v{gTp~_7pX2Bm{WMXGD8&lVnN5J%>hVXaOln{a+9S|F$?SG5K9cf`G&SC
z)q^S|DkY<sxJe#N7lf7x?y@xqJ1iM;KrbC}J&Z1dh!MEPUtU_;S^%00kPjr`4?u4|
zw48UQqM5C-#fT-bz9Sq%<TTfM+Eaj~ZfxwTc=0(${kBN?Lr>gzp*r_X@*;uR$g2U|
z8Ss_B(Gmr~M<xo+>oAMXYnEVU#rEBOIsMVBu>pE;^h*);r)`T|ZaC%U!NOdfqO(Yj
zdAPQT_+1|MhDej>*=e+cc4bSd)%Te$@h_b_#}&>&ues30&~QC;CV+JZz6>bK%gg0v
zv1$u{xR!s06F<i3&jdV~O+$71XT7}xIx?<9&vVe3g_v1#HL3Q?fDF^~@`YSv0=HGD
z{$3dDruxB91G#~hyveg>L7uFTOcRq~Lk8j<P12;X`hhWjD9;ed1N}-U!@fthn0hzd
zm#OWtV5I=9>;sZ7cWdx*?5Px=8z6~*jY|f(N91w~)AHAFvKhAa)I{G0VlqutL&GX4
zS^{4ZBx(h29q~fPl8=~xlC;DlZRj{Req7}h0?T=Xo7ZhpSxqx%y;qgbk8BoPfH5oV
zEr5Il^4==-&I92AE-^sUWCMs0J?Dx~hdd6rx-z2?<()X7PkmgJ7M_<z#ygI{%CS3I
zrUXJwM2K2pET5meCD0r2UW2c}Iov=Yi?a&Jaf!i@ykqc)$cRW$nW>oV#GkvaHIIE)
zLF4dK*sn34)9@F<u!$mrwQ;cta7+nz_*LEhQn({$tV|V5)vR$PTU=HLj61?hxuK<?
zbEGBBNDLdh=~{&6NP=@fN@{$2p>h>({3D*3ZjFR^WC%p{@CIY}SH^obyw6tVQpbX;
z1EJN-I8-aiM*H7YqaDC|#^iTKEA>CGCziufDwQe<!V&>?PtZxz57$y?RcMuFgEYEd
z+HS;uFqQ>cVxc-|qK?u4Hi?4FwFm*P@G$+ER-$UK7+B$o9(1+ukv%sTtDhDJ``Loa
z^g2A9)oVNbM^=xem6pX=$7Xk!)|aU&$aLCYIfH9-13{f8n|1FOND?NK*dq=;lkVrk
z{h?<a{7V_x15-fU0q0O&lH5C&>9lBp7uwJjBYFjFF99ddY8$spY)R0TL>?Hh2ie2h
zb?%E2^djmJ5Ji+Uh)-xG`By^jl})Zn1GbMJ2=jG}z4kbLd*Wa466tAJKRf)Gi$4Z~
z3*j|9^fTTAttPI$)zZ=xqg;zjk|2}7NIv{NLt`P>wh-wN;61yWN{`d^@Y5jT?NaQ+
zMw3aQi^)08$nRVixD<46Jm_Iz)WoJpC~??gYF8}i*ARYHAO`Tb<J-Art;(WB>fuB^
zD?9Y5&YLGX`m@(?L-}wd|A15)rc}~~`6R^8C5f*j4>=^l2|qMq53wMZToY?<Qns3(
zPh`<Ca6h<;s953{-12Cbr%r#!J=PqkyWP%swAz4HgF|}g9hh2V+hSQ?n^<KQBeW*L
zUVY1a3I0UVwJa@|0tJ$gj+TN~4-M&?Jpag|gFsHXzL<|z3aYDsp(?6sinnwc%!4+#
z5~~2LLvvLc|5(}&ymGtR=?@kOqD7#!8JuPyh78@yxad|VRn<!jc^bhhP@Wv;NgDXT
zbxq>>=@iB<V!$UJ?9gBxr&IWZM^MAKte(oNXHMrJmDjl9xm~>nK-ik|BR8679J^I)
z3oS4P7hqj3Y&sPtf(Ih(z6jYYh-?Nst>9Z!io)$GK4U+W(#9MoJt}SIeYbZ7DXc!s
zD<YN)sGMyj2tGHum)lN*sKLA$J-c3+IZ{-3g355#)%B41b#(VLg{OCrG}IzIOkfHY
z6AP4WVIPfYefj9TK=e?6@q`H&F@?U>=A7l=k2rt1vVu}1bfRn#vzSA7d~>0}66oWq
zqyMgQ@8u}x3F0RO7B<k&4$+a5jSq?ZvjxG~8_L{ovKX6H)<l*wsV2g|7x~PEqvp52
zLRLsaD;TA^5)H10Dt>WENrg%6F!}DDnx?|-nw(6RYAu`1X0!$+$2?MEP#U-Bu&vNY
zGgQ%gpgju?XN7M|lD9!>IxD33Q)w3tP)ShjqN2>VLo&Vtt$^dx_|)_+*VZlr;#$q+
z*%{lAb<*&<Z|o(^4yeucE~R9xN@2*;4a?m3r%)N@tYGqhuC1ar^XRfd%F~rbGGX*n
zYVqv6F_|?tT!VssdN(6d<=16LGoTk0&?j1c<n!I*>6;t7$WoDd_zw!ZOf6<iW=niy
zbAO#W|9@=yKRzRXDbT1DI!n$lAX5yjJIMWX4lP=|IOy72RCKbQ==#5o6hH3$Cr==5
c?u0kAx!+!vHjh&0A6DL$ZMio#{rSXy0Ql~ZGXMYp

literal 0
HcmV?d00001

diff --git a/tests/suite/layout/flow/footnote.typ b/tests/suite/layout/flow/footnote.typ
index 3230c3da0..636023516 100644
--- a/tests/suite/layout/flow/footnote.typ
+++ b/tests/suite/layout/flow/footnote.typ
@@ -286,3 +286,8 @@ B #footnote[b]
 --- issue-4454-footnote-ref-numbering ---
 // Test that footnote references are numbered correctly.
 A #footnote(numbering: "*")[B]<fn>, C @fn, D @fn, E @fn.
+
+--- issue-5354-footnote-empty-frame-infinite-loop ---
+// Test whether an empty footnote would cause infinite loop
+#show footnote.entry: it => {}
+#lorem(3) #footnote[A footnote]