From 559af669c77a3b3b6de0376f177ebbba5ebd0328 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Tue, 19 Jul 2022 22:47:39 +1000
Subject: [PATCH] Remove out-of-date column computation in show-whitespaces

Now that we compute display buffer on whole lines, it does not make
sense to compute the tab padding based off the window column position

Fixes #4674
---
 src/highlighters.cc                                           | 4 +---
 .../4674-show-whitespaces-horizontal-scroll-assert/cmd        | 1 +
 .../4674-show-whitespaces-horizontal-scroll-assert/in         | 1 +
 .../4674-show-whitespaces-horizontal-scroll-assert/rc         | 2 ++
 .../4674-show-whitespaces-horizontal-scroll-assert/script     | 2 ++
 5 files changed, 7 insertions(+), 3 deletions(-)
 create mode 100644 test/regression/4674-show-whitespaces-horizontal-scroll-assert/cmd
 create mode 100644 test/regression/4674-show-whitespaces-horizontal-scroll-assert/in
 create mode 100644 test/regression/4674-show-whitespaces-horizontal-scroll-assert/rc
 create mode 100644 test/regression/4674-show-whitespaces-horizontal-scroll-assert/script

diff --git a/src/highlighters.cc b/src/highlighters.cc
index 4b9540b6..39fd28fd 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -1061,7 +1061,6 @@ private:
         const int tabstop = context.context.options()["tabstop"].get<int>();
         auto whitespaceface = context.context.faces()["Whitespace"];
         const auto& buffer = context.context.buffer();
-        auto win_column = context.setup.first_column;
         for (auto& line : display_buffer.lines())
         {
             for (auto atom_it = line.begin(); atom_it != line.end(); ++atom_it)
@@ -1085,8 +1084,7 @@ private:
                         if (cp == '\t')
                         {
                             const ColumnCount column = get_column(buffer, tabstop, coord);
-                            const ColumnCount count = tabstop - (column % tabstop) -
-                                                      std::max(win_column - column, 0_col);
+                            const ColumnCount count = tabstop - (column % tabstop);
                             atom_it->replace(m_tab + String(m_tabpad[(CharCount)0], count - m_tab.column_length()));
                         }
                         else if (cp == ' ')
diff --git a/test/regression/4674-show-whitespaces-horizontal-scroll-assert/cmd b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/cmd
new file mode 100644
index 00000000..f13d7ddb
--- /dev/null
+++ b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/cmd
@@ -0,0 +1 @@
+gl
diff --git a/test/regression/4674-show-whitespaces-horizontal-scroll-assert/in b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/in
new file mode 100644
index 00000000..21417bda
--- /dev/null
+++ b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/in
@@ -0,0 +1 @@
+										foobar
diff --git a/test/regression/4674-show-whitespaces-horizontal-scroll-assert/rc b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/rc
new file mode 100644
index 00000000..c1f67a84
--- /dev/null
+++ b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/rc
@@ -0,0 +1,2 @@
+add-highlighter window/ show-whitespaces
+add-highlighter window/ number-lines
diff --git a/test/regression/4674-show-whitespaces-horizontal-scroll-assert/script b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/script
new file mode 100644
index 00000000..573e827f
--- /dev/null
+++ b/test/regression/4674-show-whitespaces-horizontal-scroll-assert/script
@@ -0,0 +1,2 @@
+ui_out -ignore 1
+ui_out '{ "jsonrpc": "2.0", "method": "draw", "params": [[[{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": " 1│" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": ["final_fg"] }, "contents": "       →       →       →       →       →       →       →       →       " }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "fooba" }, { "face": { "fg": "black", "bg": "white", "underline": "default", "attributes": [] }, "contents": "r" }]], { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, { "fg": "blue", "bg": "default", "underline": "default", "attributes": [] }] }'