Clean up "strip control characters" changes

Simplify these and move the sanitization closer to the point of output.

Stop worrying about control characters beyond what PCRE2 reports in
"[[:cntrl:]]" for clarity.

share/functions/fish_fossil_prompt.fish

@@ -48,10 +48,7 @@ function fish_fossil_prompt --description 'Write out the fossil prompt'
 
     echo -n ' ('
     set_color magenta
-    # Strip control characters to avoid injecting terminal escape sequences into the prompt.
-    # Raw C1 bytes are stored in fish's private-use encoding at U+F680-U+F69F.
-    set branch (string replace -ra '[\x00-\x1f\x7f-\x9f\x{f680}-\x{f69f}]' '' -- $branch)
-    echo -n "$branch"
+    echo -n "$branch" | string replace -ra '[[:cntrl:]]' ''
     set_color --reset
     echo -n '|'
     #set -l repo_status (fossil changes --differ 2>/dev/null | string match -rv '\w:|^\s' | string split " " -f1 | sort -u)

share/functions/fish_git_prompt.fish

@@ -369,6 +369,9 @@ function fish_git_prompt --description "Prompt function for Git"
     end
 
     set b (string replace refs/heads/ '' -- $b)
+    # Strip control characters before display.
+    set b (string replace -ra '[[:cntrl:]]' '' -- $b)
+    set r (string replace -ra '[[:cntrl:]]' '' -- $r)
     if string match -qr '^\d+$' "$__fish_git_prompt_shorten_branch_len"
         set -q __fish_git_prompt_shorten_branch_char_suffix
         and set -l char -c "$__fish_git_prompt_shorten_branch_char_suffix"
@@ -495,8 +498,6 @@ function __fish_git_prompt_operation_branch_bare --description "fish_git_prompt
     set -l step
     set -l total
 
-    # Strip control characters from these dot-files before showing them in the prompt.
-    # (git itself does not validate the contents of rebase-merge/rebase-apply state files).
     if test -d $git_dir/rebase-merge
         set branch (cat $git_dir/rebase-merge/head-name 2>/dev/null)
         set step (cat $git_dir/rebase-merge/msgnum 2>/dev/null)
@@ -529,6 +530,10 @@ function __fish_git_prompt_operation_branch_bare --description "fish_git_prompt
         end
     end
 
+    if test -n "$step" -a -n "$total"
+        set operation "$operation $step/$total"
+    end
+
     if test -z "$branch"
         if not set branch (command git symbolic-ref HEAD 2>/dev/null)
             set detached yes
@@ -565,16 +570,6 @@ function __fish_git_prompt_operation_branch_bare --description "fish_git_prompt
         end
     end
 
-    for var_name in branch step total
-        if set -q $var_name[1]
-            set $var_name (string replace -ra '[\x00-\x1f\x7f-\x9f\x{f680}-\x{f69f}]' '' -- $$var_name)
-        end
-    end
-
-    if test -n "$step" -a -n "$total"
-        set operation "$operation $step/$total"
-    end
-
     echo $operation
     echo $branch
     echo $detached

share/functions/fish_hg_prompt.fish

@@ -30,17 +30,15 @@ function fish_hg_prompt --description 'Write out the hg prompt'
     set -l root (fish_print_hg_root)
     or return 1
 
-    # Read branch and bookmark.
-    # Strip control characters before showing branch/bookmark names in the prompt.
-    # Raw C1 bytes are stored in fish's private-use encoding at U+F680-U+F69F.
-    # (they live under .hg/ and are not validated by hg itself in this code path).
+    # Read branch and bookmark
     set -l branch (cat $root/branch 2>/dev/null; or echo default)
-    set branch (string replace -ra '[\x00-\x1f\x7f-\x9f\x{f680}-\x{f69f}]' '' -- $branch)
     if set -l bookmark (cat $root/bookmarks.current 2>/dev/null)
-        set bookmark (string replace -ra '[\x00-\x1f\x7f-\x9f\x{f680}-\x{f69f}]' '' -- $bookmark)
         set branch "$branch|$bookmark"
     end
 
+    # Strip control characters for display.
+    set branch (string replace -ra '[[:cntrl:]]' '' -- $branch)
+
     if not set -q fish_prompt_hg_show_informative_status
         set_color --reset
         echo -n " ($branch)"

share/prompts/minimalist.fish

@@ -3,7 +3,7 @@
 
 function fish_prompt
     set_color $fish_color_cwd
-    echo -n (prompt_pwd | path basename)
+    echo -n (path basename $PWD)
     set_color --reset
     echo -n ' ) '
 end

tests/checks/vcs-prompts.fish

@@ -15,7 +15,7 @@ set -gx PATH $tmp/bin $PATH
 
 mkdir -p $tmp/hgrepo/.hg
 touch $tmp/hgrepo/.hg/dirstate
-printf 'main\e]0;OHNO\a\x7f\u0080\x80' >$tmp/hgrepo/.hg/branch
+printf 'main\e]0;OHNO\a\x7f' >$tmp/hgrepo/.hg/branch
 
 cd $tmp/hgrepo
 fish_hg_prompt
@@ -27,7 +27,7 @@ mkdir $tmp/gitrepo
 cd $tmp/gitrepo
 git init -q
 mkdir .git/rebase-merge
-printf 'refs/heads/main\e]0;OHNO\a\x7f\u0080\x80' >.git/rebase-merge/head-name
+printf 'refs/heads/main\e]0;OHNO\a\x7f' >.git/rebase-merge/head-name
 : >.git/rebase-merge/msgnum
 : >.git/rebase-merge/end