From eb932941715f56297d9c5093b70b6d1d3e88d7c0 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Thu, 21 Aug 2025 14:50:16 +0200
Subject: [PATCH] Fix logical order in bidirectional lines (#6796)

---
 crates/typst-layout/src/inline/line.rs    |   2 +-
 crates/typst-layout/src/inline/prepare.rs |  18 +++++++++++++-----
 tests/ref/counter-rtl.png                 | Bin 0 -> 1609 bytes
 tests/suite/introspection/counter.typ     |   9 +++++++++
 4 files changed, 23 insertions(+), 6 deletions(-)
 create mode 100644 tests/ref/counter-rtl.png

diff --git a/crates/typst-layout/src/inline/line.rs b/crates/typst-layout/src/inline/line.rs
index 311dc7c69..ba48bfe59 100644
--- a/crates/typst-layout/src/inline/line.rs
+++ b/crates/typst-layout/src/inline/line.rs
@@ -271,7 +271,7 @@ fn collect_range<'a>(
     items: &mut Items<'a>,
     fallback: &mut Option<ItemEntry<'a>>,
 ) {
-    for (idx, (subrange, item)) in p.slice(range.clone()).enumerate() {
+    for (idx, (subrange, item)) in p.slice(range.clone()) {
         // All non-text items are just kept, they can't be split.
         let Item::Text(shaped) = item else {
             items.push(item, idx);
diff --git a/crates/typst-layout/src/inline/prepare.rs b/crates/typst-layout/src/inline/prepare.rs
index ab39bdb14..1c876ca94 100644
--- a/crates/typst-layout/src/inline/prepare.rs
+++ b/crates/typst-layout/src/inline/prepare.rs
@@ -34,8 +34,12 @@ impl<'a> Preparation<'a> {
         &self.items[idx]
     }
 
-    /// Iterate over the items that intersect the given `sliced` range.
-    pub fn slice(&self, sliced: Range) -> impl Iterator<Item = &(Range, Item<'a>)> {
+    /// Iterate over the items that intersect the given `sliced` range alongside
+    /// their indices in `self.items` and their ranges in the paragraph's text.
+    pub fn slice(
+        &self,
+        sliced: Range,
+    ) -> impl Iterator<Item = (usize, &(Range, Item<'a>))> {
         // Usually, we don't want empty-range items at the start of the line
         // (because they will be part of the previous line), but for the first
         // line, we need to keep them.
@@ -43,9 +47,13 @@ impl<'a> Preparation<'a> {
             0 => 0,
             n => self.indices.get(n).copied().unwrap_or(0),
         };
-        self.items[start..].iter().take_while(move |(range, _)| {
-            range.start < sliced.end || range.end <= sliced.end
-        })
+        self.items
+            .iter()
+            .enumerate()
+            .skip(start)
+            .take_while(move |(_, (range, _))| {
+                range.start < sliced.end || range.end <= sliced.end
+            })
     }
 }
 
diff --git a/tests/ref/counter-rtl.png b/tests/ref/counter-rtl.png
new file mode 100644
index 0000000000000000000000000000000000000000..9fc57c2364284f63187abc6f3c041f7dbcf251e2
GIT binary patch
literal 1609
zcmV-P2DbT$P)<h;3K|Lk000e1NJLTq00651001cn00000Z~KN8000IMNkl<Zc-rmO
z|4-C)9KiAZini9)YLyd7UGh~zB_l{9%|eV6F(pM&T8N^CUywjZMG>jQROE|*kdVd~
zO%O;04TBWFaU8-SUyg%=<GACFyZb!bKKI%5HV!v8Ty6LG`Lp+)@AnU%*Xt$zKVEXQ
zI$9mAj#fvjqm`#!=P855B^L*HA?}?1O$kW;Dk-iqKC4ylWR0yq9%}*;H>j5Ufvw_f
zY!ntoVoM0bhB56B*h;vCjl?`tl_$`hc_<6ez1etk<By0UWp-M#OE&=EXUWV4&hFx1
zE~4AXE5KI8C}221*i}TKndR8(tpn)H*pAh&IbVaVVt|Hqz-0kyy5xZX-u)0#2~hfe
zi=EbFTup%9o!Sk+*}w!J9iTMAs2;+#QO+}BE-GLEI2?m0U=S=_pdYhPdGh+ZQv!2t
zg2oKJ?~DNaDYkYBm`r+DL4cEc;uRIBfz`Rd4=0e+dNv`o{u%-FWPNR?wKgo>|2)v;
z%Z&)@yI%YNSlfhX`|ogPs#`iH*D(-W^#BJOfWN~LDFR?L;?)2Xy9<EBKR#*o9z*o8
z0xDjaTS})NFfbcP+6R)m(*&vY;yNHsv#N3Y)@{%n1mI0+mbI1F%n*DPQCtaoLplIr
zt^@1pfRl}uR;XElNV$M!@81QWeI?Ko`lNNH8qw!%mX+Jo01LH%*9g>km|@t2_?cE}
z-C7BpNq;ZiJYH+jVjb--Uj|asBXpo&?|=R0B%t>7HL(f1Hu{B*p583os{W|oLeCNC
zduLZjJs5obq7&k_e&Ka<z*_}C`>KAorBg2e`WRmoaPqB)-QUNqowJk8nTP^(k&EB|
z3?O4oWnmFelbg2<c=$?oU1~f4s(EJ_uT?G^McMiYphE{3T4Zek0LE*@=PunGh532_
z+C0bTYzHv3%4H^ima@Xqnl8vqL$sn4?R^8*V>AH6SBgq5|6@k*LR7T`p|uy0a90Pw
zgKmJH))u)D(U7eDd1rwW0K2C*W6#b)fVx>p*wZy1U~JW#zR8_iK`DTyb`-lR=k$VB
zF2la*Wguw(5SZLn&FVKjUXNlTSu<ujyLK=E`JyTAZ~XKk_JI+e#bA2&A&x!kKij%p
z2Y}+*r5;dk`6lO-8C#ugJZ-GH{@NpKRfDaeer(+y#D*sI__rAV+N(yOI(UC_zQI~j
zYp=D<KNo=bjI=)BbSyj45t&roh;CiuX%7R_mNy{k*60Bc(y*1a-;7ABl@7UJdp+}K
zy|4_>M6`tfxTvUHqz7^{e>-BQHC6F3010XkXRHt<h1^Tu2t72NsTYv!yblcN_ztUY
z3aT&;4i=stLUKC}pgIOgY0(zwp*pV_Bx^K4;a;F0kT2+rM4GYtGk|$&e8z9p$B)ca
z0vu2IR4MLR`}}Kwas{G=^6Z4KTtW&k<pMYS08pd@L-~l#M?Xl2p7&9th4MZS-g^Kn
z{3ZM{aN2-qy6IrtGWW1QQI!EFqJW*JkR(oNKx)0T3<y1GbREC-L|WFSR7CrZitmc%
zZ2^|a5FN;4c+aB4w_v^!So|1Z&j4^`Goq1sP_}4GzQCD8pduD<LFER_!fNGR9&ZXd
zCdc3g2=2fy(OBI`Qn_iQ*4zZZSiEQ5xUE7IsJ#FN*-;GS?7%WbfQ|7MfXAQwrSmHT
zAhA-R99VD*Fops&&*}y+X0GALdOd(TkS0S;7!cCe`w1}j902#+H61>U0DPf(IQ-a2
z4_!0bq22^PSFu(Fc=TfqdIT^Mq8zvNhY%I@KF5KrhYkSh@TED&nt`FU&eL2x+=DCF
zREj8AcEM-Pet?pE08Y)GHq+h1H{Q^^7*Xx!fne9=U4ZPnV;w;2QYU9uPmi!B{AB<L
zUY4}kALawdV~=Fs2Q*0~7l3M?@3T`H0947{&;5V(1i*A~IrgL!0MO{tfgM_30EX8m
zP3|n1ss&gOZNi@9BLI2c&Db;K3^3-L#^kmho?FpUUL;_jV%pJv8jh)%!0In+AD+7+
zFv+b{t^YK<oQd@84f--=hzVE<RxkOs!LhqIS{<#9*5~jqeZjz;Ei8K100000NkvXX
Hu0mjfTul9K

literal 0
HcmV?d00001

diff --git a/tests/suite/introspection/counter.typ b/tests/suite/introspection/counter.typ
index b0657a2ad..10ad5468d 100644
--- a/tests/suite/introspection/counter.typ
+++ b/tests/suite/introspection/counter.typ
@@ -174,3 +174,12 @@ B
 #context test(c.get(), (100000000002,))
 #c.update(n => n + 2)
 #context test(c.get(), (100000000004,))
+
+--- counter-rtl ---
+#set page(width: auto)
+#let c = counter("c")
+#let s = context c.display() + c.step()
+#let tree = [درخت]
+#let line = [A #s B #tree #s #tree #s #tree C #s D #s]
+#line \
+#line