Don't print greetings in interactive read in fake-interactive shell

If a user passes "-i" when running a script, they ought to expect
weird behavior i.e. fish might run the user's interactive-only
configuration which might print things to TTY etc.  But at least
for our part of the configuration, we can avoid depending on the
user-settable interactive bit.

__fish_config_interactive is already only called when we paint the
first prompt, either for a prompt (which implies we're an interactive
shell) or for builtin read (which does not imply anything about the
interactivity of the shell).

Only print greetings when not in interactive read. Notably, "status
is-interactive-read" is not overridable by the user.

This helps us get rid of more "status is-interactive" switches.

share/functions/__fish_config_interactive.fish

@@ -29,14 +29,14 @@ function __fish_config_interactive -d "Initializations that should be performed
     # The default just prints a variable of the same name.
     #
     # NOTE: This status check is necessary to not print the greeting when `read`ing in scripts. See #7080.
-    if status is-interactive
+    if not status is-interactive-read
         and functions -q fish_greeting
         fish_greeting
     end
 
     # Display SHELL_WELCOME if set. This is a standard environment variable (introduced by
     # systemd v257) intended for shells to display when they first initialize.
-    if status is-interactive
+    if not status is-interactive-read
         and set -q SHELL_WELCOME[1]
         string join -- ' ' $SHELL_WELCOME
     end

tests/checks/tmux-read.fish

@@ -1,14 +1,16 @@
-#RUN: %fish %s
+#RUN: fish=%fish %fish %s
 #REQUIRES: command -v tmux
 #REQUIRES: test -z "$CI"
 
-isolated-tmux-start -C '
-    function fish_greeting
-        set -l name (read)
-        echo hello $name
-    end
+printf >?$__fish_config_dir/functions/fish_greeting.fish %s \
+'function fish_greeting
+    set -l name (read)
+    echo hello $name
+end
 '
 
+isolated-tmux-start
+
 isolated-tmux send-keys name Enter 'echo foo' Enter
 tmux-sleep
 isolated-tmux capture-pane -p
@@ -17,3 +19,12 @@ isolated-tmux capture-pane -p
 # CHECK: prompt 0> echo foo
 # CHECK: foo
 # CHECK: prompt 1>
+
+isolated-tmux send-keys C-l 'SHELL_WELCOME=hello $fish -ic "read --prompt-str=R"' Enter
+tmux-sleep
+isolated-tmux send-keys C-c
+tmux-sleep
+isolated-tmux capture-pane -p
+# CHECK: prompt 1> SHELL_WELCOME=hello $fish -ic "read --prompt-str=R"
+# CHECK: R
+# CHECK: prompt 2>

tests/test_functions/isolated-tmux-start.fish

@@ -41,9 +41,13 @@ function isolated-tmux-start --wraps fish
 
     set -l fish (status fish-path)
     set -l size -x 80 -y 10
+    set -l greeting_file
+    if not test -f $greeting_file
+        printf >$__fish_config_dir/functions/fish_greeting.fish %s \
+            'function fish_greeting; end' 2>/dev/null
+    end
     isolated-tmux new-session $size -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 ""