From 3a375c239955744d70041d30d40e9307dc05b3d0 Mon Sep 17 00:00:00 2001
From: Johannes Altmanninger <aclopte@gmail.com>
Date: Sun, 1 Aug 2021 17:41:56 +0200
Subject: [PATCH] reader: fix regressions when moving between lines

Fixes some regressions from 35ca42413 ("Simplify some parse_util functions").
The tmux tests are not beautiful but I find them easy to write.
Probably a pexpect test would also be enough here?
---
 src/parse_util.cpp          | 19 ++++++++++---------
 tests/checks/tmux-bind.fish | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 9 deletions(-)
 create mode 100644 tests/checks/tmux-bind.fish

diff --git a/src/parse_util.cpp b/src/parse_util.cpp
index be5a8e5eb..9671bfeec 100644
--- a/src/parse_util.cpp
+++ b/src/parse_util.cpp
@@ -54,8 +54,8 @@ int parse_util_lineno(const wcstring &str, size_t offset) {
 
 int parse_util_get_line_from_offset(const wcstring &str, size_t pos) {
     // Return the line pos is on, or -1 if it's after the end.
-    if (str.length() > pos) return -1;
-    return std::count(str.begin() + pos, str.end(), L'\n');
+    if (pos > str.length()) return -1;
+    return std::count(str.begin(), str.begin() + pos, L'\n');
 }
 
 size_t parse_util_get_offset_from_line(const wcstring &str, int line) {
@@ -63,10 +63,11 @@ size_t parse_util_get_offset_from_line(const wcstring &str, int line) {
     if (line < 0) return static_cast<size_t>(-1);
     if (line == 0) return 0;
 
-    ssize_t i = 0;
-    while (auto pos = str.find(L'\n')) {
-        i++;
-        if (i == line) return pos + 1;
+    size_t pos = -1;
+    int count = 0;
+    while ((pos = str.find(L'\n', pos + 1)) != wcstring::npos) {
+        count++;
+        if (count == line) return pos + 1;
     }
     return static_cast<size_t>(-1);
 }
@@ -222,7 +223,6 @@ long parse_util_slice_length(const wchar_t *in) {
     return -1;
 }
 
-
 int parse_util_locate_cmdsubst_range(const wcstring &str, size_t *inout_cursor_offset,
                                      wcstring *out_contents, size_t *out_start, size_t *out_end,
                                      bool accept_incomplete, bool *out_is_quoted) {
@@ -1112,8 +1112,9 @@ static bool detect_errors_in_decorated_statement(const wcstring &buff_src,
     const wcstring &com = dst.command.source(buff_src, storage);
     if (com == L"$status") {
         parse_error_offset_source_start(parse_errors, source_start);
-        errored = append_syntax_error(parse_errors, source_start,
-                                      _(L"$status is not valid as a command. See `help conditions`"));
+        errored =
+            append_syntax_error(parse_errors, source_start,
+                                _(L"$status is not valid as a command. See `help conditions`"));
     }
 
     const wcstring &unexp_command = dst.command.source(buff_src, storage);
diff --git a/tests/checks/tmux-bind.fish b/tests/checks/tmux-bind.fish
new file mode 100644
index 000000000..d15cb85d7
--- /dev/null
+++ b/tests/checks/tmux-bind.fish
@@ -0,0 +1,36 @@
+#RUN: %fish -C 'set -g fish %fish' %s
+#REQUIRES: command -v tmux
+
+set fish (builtin realpath $fish)
+
+# Isolated tmux.
+set -g tmpdir (mktemp -d)
+
+# Don't CD elsewhere, because tmux socket file is relative to CWD. Using
+# absolute path to socket file is prone to 'socket file name too long' error.
+cd $tmpdir
+
+set -g tmux tmux -S .tmux-socket -f /dev/null
+
+set -g sleep sleep .1
+set -q CI && set sleep sleep 1
+
+
+$tmux new-session -x 80 -y 10 -d $fish -C '
+    # This is similar to "tests/interactive.config".
+    function fish_greeting; end
+    function fish_prompt; printf "prompt $status_generation> "; end
+    # No autosuggestion from older history.
+    set fish_history ""
+'
+$sleep # Let fish draw a prompt.
+
+# Test moving around with up-or-search on a multi-line commandline.
+$tmux send-keys 'echo 12' M-Enter 'echo ab' C-p 345 C-n cde
+$sleep
+$tmux capture-pane -p
+# CHECK: prompt 0> echo 12345
+# CHECK: echo abcde
+
+$tmux kill-server
+rm -r $tmpdir