Trigger abbreviations after inserting process separators

On

    a;

we don't expand the abbreviation because the cursor is right of semicolon,
not on the command token. Fix this by making sure that we call expand-abbr
with the cursor on the semicolon which is the end of the command token.
(Now that our bind command execution order is less surprising, this is doable.)

This means that we need to fix the cursor after successfully expanding
an abbreviation. Do this by setting the position explicitly even when no
--set-position is in effect.

An earlier version of this patch used

    bind space self-insert backward-char expand-abbr or forward-char

The problem with that (as a failing test shows) was that given "abbr m
myabbr", after typing "m space ctrl-z", the cursor would be after the "m",
not after the space.  The second space removes the space, not changing the
cursor position, which is weird.  I initially tried to fix this by adding
a hack to the undo group logic, to always restore the cursor position from
when begin-undo-group was used.

    bind space self-insert begin-undo-group backward-char expand-abbr end-undo-group or forward-char

However this made test_torn_escapes.py fail for mysterious reasons.
I believe this is because that test registers and triggers a SIGUSR1 handler;
since the signal handler will rearrange char events, that probably messes
with the undo group guards.

I resorted to adding a tailor-made readline cmd. We could probably remove
it and give the new behavior to expand-abbr, not sure.

Fixes #9730

CHANGELOG.rst

@@ -104,6 +104,7 @@ Interactive improvements
 - fish no longer fails to open a fifo if interrupted by a terminal resize signal (:issue:`10250`).
 - ``read --help`` and friends no longer ignore redirections. This fixes a regression in version 3.1 (:issue:`10274`).
 - Command abbreviations (those with ``--position command`` or without a ``--position``) now also expand after decorators like ``command`` (:issue:`10396`).
+- Abbreviations now expand after process separators like ``;`` and ``|``. This fixes a regression in version 3.6 (:issue:`9730`).
 
 New or improved bindings
 ^^^^^^^^^^^^^^^^^^^^^^^^

share/functions/__fish_shared_key_bindings.fish

@@ -117,22 +117,20 @@ function __fish_shared_key_bindings -d "Bindings shared between emacs and vi mod
         or exit # protect against invalid $argv
 
         # Space and other command terminators expands abbrs _and_ inserts itself.
-        bind --preset $argv " " self-insert expand-abbr
-        bind --preset $argv ";" self-insert expand-abbr
-        bind --preset $argv "|" self-insert expand-abbr
-        bind --preset $argv "&" self-insert expand-abbr
-        bind --preset $argv ">" self-insert expand-abbr
-        bind --preset $argv "<" self-insert expand-abbr
-        bind --preset $argv shift-enter expand-abbr "commandline -i \n"
-        $legacy_bind --preset $argv \e\[27\;2\;13~ expand-abbr "commandline -i \n" # Sent with XTerm.vt100.formatOtherKeys: 0
-        bind --preset $argv alt-enter expand-abbr "commandline -i \n"
-        # Closing a command substitution expands abbreviations
-        bind --preset $argv ")" self-insert expand-abbr
-        # Ctrl-space inserts space without expanding abbrs
+        bind --preset $argv " " self-insert expand-abbr-backtrack
+        bind --preset $argv ";" self-insert expand-abbr-backtrack
+        bind --preset $argv "|" self-insert expand-abbr-backtrack
+        bind --preset $argv "&" self-insert expand-abbr-backtrack
+        bind --preset $argv ">" self-insert expand-abbr-backtrack
+        bind --preset $argv "<" self-insert expand-abbr-backtrack
+        bind --preset $argv shift-enter "commandline -i \n" expand-abbr-backtrack
+        $legacy_bind --preset $argv \e\[27\;2\;13~ "commandline -i \n" expand-abbr-backtrack # Sent with XTerm.vt100.formatOtherKeys: 0
+        bind --preset $argv alt-enter "commandline -i \n" expand-abbr-backtrack
+        bind --preset $argv ")" self-insert expand-abbr-backtrack # Closing a command substitution.
         bind --preset $argv ctrl-space 'test -n "$(commandline)" && commandline -i " "'
         bind --preset $argv -k nul 'test -n "$(commandline)" && commandline -i " "'
         # Shift-space behaves like space because it's easy to mistype.
-        bind --preset $argv shift-space 'commandline -i " "; commandline -f expand-abbr'
+        bind --preset $argv shift-space 'commandline -i " "' expand-abbr-backtrack
 
         bind --preset $argv enter execute
         bind --preset $argv ctrl-j execute

src/input.rs

@@ -166,6 +166,7 @@ const INPUT_FUNCTION_METADATA: &[InputFunctionMetadata] = &[
     make_md(L!("execute"), ReadlineCmd::Execute),
     make_md(L!("exit"), ReadlineCmd::Exit),
     make_md(L!("expand-abbr"), ReadlineCmd::ExpandAbbr),
+    make_md(L!("expand-abbr-backtrack"), ReadlineCmd::ExpandAbbrBacktrack),
     make_md(L!("force-repaint"), ReadlineCmd::ForceRepaint),
     make_md(L!("forward-bigword"), ReadlineCmd::ForwardBigword),
     make_md(L!("forward-char"), ReadlineCmd::ForwardChar),

src/input_common.rs

@@ -111,6 +111,7 @@ pub enum ReadlineCmd {
     FuncAnd,
     FuncOr,
     ExpandAbbr,
+    ExpandAbbrBacktrack,
     DeleteOrExit,
     Exit,
     CancelCommandline,

src/reader.rs

@@ -3069,6 +3069,13 @@ impl ReaderData {
                     self.inputter.function_set_status(false);
                 }
             }
+            rl::ExpandAbbrBacktrack => {
+                if self.expand_abbreviation_at_cursor(2) {
+                    self.inputter.function_set_status(true);
+                } else {
+                    self.inputter.function_set_status(false);
+                }
+            }
             rl::Undo | rl::Redo => {
                 let (elt, el) = self.active_edit_line_mut();
                 let ok = if c == rl::Undo { el.undo() } else { el.redo() };

tests/pexpects/abbrs.py

@@ -29,6 +29,9 @@ expect_str(r"<beta >")
 send(r"echo alpha ?")
 expect_str(r"<echo alpha >")
 
+send(r"alpha;?")
+expect_str(r"<beta;>")
+
 # Abbreviation expansions may have multiple words.
 sendline(r"abbr --add emacsnw emacs -nw -l")
 expect_prompt()