From 909e34f68a969275bc9b14c63e03d5d131823d91 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sat, 22 Jan 2022 09:44:13 -0700
Subject: [PATCH] [unsafe-to-concat] Adjust Arabic-joining start boundary
 condition more

---
 src/hb-ot-shape-complex-arabic.cc                |  14 ++++++++++++--
 test/shape/data/in-house/Makefile.sources        |   1 +
 .../34da9aab7bee86c4dfc3b85e423435822fdf4b62.ttf | Bin 0 -> 1904 bytes
 test/shape/data/in-house/meson.build             |   1 +
 .../data/in-house/tests/unsafe-to-concat.tests   |   1 +
 5 files changed, 15 insertions(+), 2 deletions(-)
 create mode 100644 test/shape/data/in-house/fonts/34da9aab7bee86c4dfc3b85e423435822fdf4b62.ttf
 create mode 100644 test/shape/data/in-house/tests/unsafe-to-concat.tests

diff --git a/src/hb-ot-shape-complex-arabic.cc b/src/hb-ot-shape-complex-arabic.cc
index 5eec4af37..2298aa92f 100644
--- a/src/hb-ot-shape-complex-arabic.cc
+++ b/src/hb-ot-shape-complex-arabic.cc
@@ -321,9 +321,19 @@ arabic_joining (hb_buffer_t *buffer)
       info[prev].arabic_shaping_action() = entry->prev_action;
       buffer->unsafe_to_break (prev, i + 1);
     }
-    else if (2 <= state && state <= 5) /* States that have a possible prev_action. */
+    else
     {
-      buffer->unsafe_to_concat (prev, i + 1);
+      if (prev == UINT_MAX)
+      {
+        if (this_type >= JOINING_TYPE_R)
+	  buffer->unsafe_to_concat_from_outbuffer (0, i + 1);
+      }
+      else
+      {
+	if (this_type >= JOINING_TYPE_R ||
+	    (2 <= state && state <= 5) /* States that have a possible prev_action. */)
+	  buffer->unsafe_to_concat (prev, i + 1);
+      }
     }
 
     info[i].arabic_shaping_action() = entry->curr_action;
diff --git a/test/shape/data/in-house/Makefile.sources b/test/shape/data/in-house/Makefile.sources
index 01047d548..02c9e914b 100644
--- a/test/shape/data/in-house/Makefile.sources
+++ b/test/shape/data/in-house/Makefile.sources
@@ -59,6 +59,7 @@ TESTS = \
 	tests/tibetan-contractions-2.tests \
 	tests/tibetan-vowels.tests \
 	tests/tt-kern-gpos.tests \
+	tests/unsafe-to-concat.tests \
 	tests/use-indic3.tests \
 	tests/use-marchen.tests \
 	tests/use-syllable.tests \
diff --git a/test/shape/data/in-house/fonts/34da9aab7bee86c4dfc3b85e423435822fdf4b62.ttf b/test/shape/data/in-house/fonts/34da9aab7bee86c4dfc3b85e423435822fdf4b62.ttf
new file mode 100644
index 0000000000000000000000000000000000000000..8508fbeeb5fd773bfe3cf2b2170f2f6c74100b23
GIT binary patch
literal 1904
zcma)6U2GIp6#nk)%xu~IY$?0jvVSg1yCs$4cDr3@`6;y9t_h`EyQmG()hS(QW7{q5
zLV*M&(I^rhFeYli2jYv87)*RHCYosCgFg9SV#J8Q(L|z>_+Wyu?fBi9U8sPG_h#mv
z^WE=!=ggfm0|B5Gr{TazCOt5SEr<a6aiW_tBiUT~*w9h>7wJbbxd;2wOJgVLe?<Rs
zHg{j*+>0w6fa6vAj~|>d=6b|$m+0T1zvJ-qi9?H@SMQ^J6%b341!E$4;PB7fuP2t8
zBoKMQ`yu@j{pQJ;((xu0-_pOI{^sf8K|`rmP63M4Ynm~R&!N}x9{nryBeTX#VZ)`K
z44@{d|K?nAp)}?T%mNzo;k;=gY_>bz7B49==tP{*#Ch|YjjM|yN8DM)pSEzAd+@cz
zuOhBPyJwkfqT+cGAbX9C=9eMhH`6#}zJY3>F&gViraBWouSXy9hC*IXDD*+d;|Yg7
zo)Al89ly#t5M*r@cWa}rdp$m1XCl>=jJ0m{F|<w*&%X0+gKMwu?s{hN+LuA!zI7W?
zPk!Oe&$Q%P*7^GV$=*=sKy0Er&@tD(J(p~<mF1HlcBk?#<yID1*~VzBRaaN%*m>r;
zlUsV%=)RrXyz7F#u_Ge4a^qj=+^y+kOJktg9cXB*uMZ@*@9ve)1M_crPH+R>t%;QV
z3}J;yTpd0BjlKtJ8|$CYMr&GHVhi2j$mmFTVt+YKo+Q>=ad$0HceTaWH`EU6?uH$^
zWL4Rry6~_z>b`fh&m9<S@<gmkqR}=#70v7BPiRn{V*kRqwsUPmb5OakT(EMXTKNPU
z@H^j-?DAW~DcKw~Xu?Kzd>Tja7CyxvSh1LjGF-TPA^(_r$DeRGev#CxrH?<8>o>1I
z`o7t`d^PCQvUGJQ5@kn@A@BGBVRZmuQOooX6MO~!J205nWezRB90r0(vw6t~I&Z5F
ztXOr7h;z`We3sh4UV9aJB=9}aYE4l!RZ-N_@`GJ9GTCfK?AA9$YU~_ZUip#RyCp>&
z6BoHeq^?!DJO>X?L!OTZDmHP|xe6#!LH54A{`J*&_SulY;lu$MrONMNl9z1@Do>Ve
z1$8)6wjJoh%Vk?d99PP=2EV8(+d4LjDEd*v98O>!Q#eem5)~7S=s*|REh|Agf(&^@
zGNw_WH^kX*{kirKnI<xNGk(GH3Roa>9>;i}Aaj_}C0-HaU|^QJ5$xf<fpJD2WPE|@
zN2z5HO)w(P*^TYYoaM~Ws%TUcR>!yBrcmMjS3X(s>WmLr)h@7>BCC^UP^qAz^nbFJ
zd((W4@pl{ia|uN_geo+l3#X_OYlKTwJCDvz#Z!rGavdD#j+fVt@|ti>6iefU>Efa>
zZ&OnPHC9M!V9TMYS>vWNH9J+h>C6-+rX)QPkN2|}b{IRv9!<0br|dh4%P&)2f_Hhj
z_}>geqz8xgqlzpJ*_qa`_uKFY6l=fEm^a3$Tw%#oYC51A#&ijOSs@~_G{j_0*laPR
tm>^5u?Ys&#T!`|$?<(U}-09&Zd)87cGbJ9io<T-SukuaVo=(J`_y@4sKF|OF

literal 0
HcmV?d00001

diff --git a/test/shape/data/in-house/meson.build b/test/shape/data/in-house/meson.build
index cda01d490..2da9dab14 100644
--- a/test/shape/data/in-house/meson.build
+++ b/test/shape/data/in-house/meson.build
@@ -59,6 +59,7 @@ in_house_tests_base = [
   'tibetan-contractions-2.tests',
   'tibetan-vowels.tests',
   'tt-kern-gpos.tests',
+  'unsafe-to-concat.tests',
   'use-indic3.tests',
   'use-marchen.tests',
   'use-syllable.tests',
diff --git a/test/shape/data/in-house/tests/unsafe-to-concat.tests b/test/shape/data/in-house/tests/unsafe-to-concat.tests
new file mode 100644
index 000000000..24906fa6d
--- /dev/null
+++ b/test/shape/data/in-house/tests/unsafe-to-concat.tests
@@ -0,0 +1 @@
+../fonts/34da9aab7bee86c4dfc3b85e423435822fdf4b62.ttf;--show-flags;U+0628,U+200C,U+0628;[uni0628=1+993#2|uni0628=0+993#2]