Stop setting tty back to shell mode when a fg proc completes

Prior to this change, when a process resumes because it is brought back
to the foreground, we would reset the terminal attributes to shell mode.
This fixed #2114 but subtly introduced #7483.

This backs out 9fd9f70346, re-introducing #2114 and re-fixing #7483.
A followup fix will re-fix #2114; these are broken out separately for
bisecting purposes.

Fixes #7483.

src/proc.cpp

@@ -931,19 +931,6 @@ static bool terminal_return_from_job_group(job_group_t *jg, bool restore_attrs)
         return false;
     }
     jg->tmodes = tmodes;
-
-    // Need to restore the terminal's attributes or `bind \cF fg` will put the
-    // terminal into a broken state (until "enter" is pressed).
-    // See: https://github.com/fish-shell/fish-shell/issues/2114
-    if (restore_attrs) {
-        if (tcsetattr(STDIN_FILENO, TCSADRAIN, &shell_modes) == -1) {
-            if (errno == EIO) redirect_tty_output();
-            FLOGF(warning, _(L"Could not return shell to foreground"));
-            wperror(L"tcsetattr");
-            return false;
-        }
-    }
-
     return true;
 }
 

tests/pexpects/fg2.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+from pexpect_helper import SpawnedProc
+import subprocess
+import sys
+import time
+
+sp = SpawnedProc()
+send, sendline, sleep, expect_prompt, expect_re, expect_str = (
+    sp.send,
+    sp.sendline,
+    sp.sleep,
+    sp.expect_prompt,
+    sp.expect_re,
+    sp.expect_str,
+)
+expect_prompt()
+
+# Regression test for #7483.
+# Ensure we can background a job after a different backgrounded job completes.
+sendline("sleep 1")
+sleep(0.1)
+
+# ctrl-z - send job to background
+send("\x1A")
+sleep(0.2)
+expect_prompt("has stopped")
+
+# Bring back to fg.
+sendline("fg")
+sleep(1.0)
+
+# Now sleep is done, right?
+expect_prompt()
+sendline("jobs")
+expect_prompt("jobs: There are no jobs")
+
+# Ensure we can do it again.
+sendline("sleep 5")
+sleep(0.2)
+send("\x1A")
+sleep(0.1)
+expect_prompt("has stopped")
+sendline("fg")
+sleep(0.1) # allow tty to transfer
+send("\x03")  # control-c to cancel it