complete: tab-complete anywhere-position abbrs in non-command position

Make abbreviations with `--position anywhere` appear in the completion
menu when tabbing in argument position (e.g. `cat foo.log pg<TAB>`
shows pgr, pgrv, pjq, etc.), not just in command position.

Lift "do_file" into an enum, so we don't have to check "is_redirection"
twice, and can express more accurately the reason for not completing
abbreviations after redirection.

Co-authored-by: Johannes Altmanninger <aclopte@gmail.com>

Closes #12764

CHANGELOG.rst

@@ -12,6 +12,7 @@ Interactive improvements
 - ``fish_hg_prompt``, ``fish_git_prompt`` and ``fish_fossil_prompt`` now strip control characters from VCS state read off disk, matching ``prompt_pwd``.
 - The sample informative and minimalist prompts now use ``prompt_pwd`` instead of printing ``$PWD`` directly.
 - ``bind`` shows the file where bindings were defined (:issue:`12504`).
+- Abbreviations with ``--position=anywhere`` can now be completed in argument position, not just in command position (:issue:`12630`).
 
 For distributors and developers
 -------------------------------

src/complete.rs

@@ -1,5 +1,5 @@
 use crate::{
-    abbrs::with_abbrs,
+    abbrs::{Position, with_abbrs},
     ast::unescape_keyword,
     autoload::{Autoload, AutoloadResult},
     builtins::shared::{builtin_exists, builtin_get_desc, builtin_get_names},
@@ -689,7 +689,7 @@ fn perform_for_commandline_impl(&mut self, cmdline: WString) {
                 return;
             }
             self.complete_cmd(WString::new());
-            self.complete_abbr(L!(""));
+            self.complete_abbr(L!(""), true);
             return;
         };
 
@@ -744,7 +744,7 @@ fn perform_for_commandline_impl(&mut self, cmdline: WString) {
                 return;
             }
             // Complete command filename.
-            self.complete_abbr(current_token);
+            self.complete_abbr(current_token, true);
             self.complete_cmd(current_token.to_owned());
             return;
         }
@@ -784,10 +784,17 @@ fn perform_for_commandline_impl(&mut self, cmdline: WString) {
             }
         }
 
-        let mut do_file = false;
+        #[derive(Eq, PartialEq)]
+        enum DoFile {
+            No,
+            Yes,
+            Only,
+        }
+
+        let mut do_file = DoFile::No;
         let mut handle_as_special_cd = false;
         if in_redirection {
-            do_file = true;
+            do_file = DoFile::Only;
         } else {
             // Try completing as an argument.
             let mut arg_data = CustomArgData::new(&mut var_assignments);
@@ -817,11 +824,15 @@ fn perform_for_commandline_impl(&mut self, cmdline: WString) {
                     command_range,
                     &mut arg_data,
                 );
-                do_file = arg_data.do_file;
+                do_file = if arg_data.do_file {
+                    DoFile::Yes
+                } else {
+                    DoFile::No
+                };
 
                 // If we're autosuggesting, and the token is empty, don't do file suggestions.
                 if is_autosuggest && arg_data.current_argument.is_empty() {
-                    do_file = false;
+                    do_file = DoFile::No;
                 }
             }
 
@@ -833,10 +844,14 @@ fn perform_for_commandline_impl(&mut self, cmdline: WString) {
         // Maybe apply variable assignments.
         let block = self.apply_var_assignments(&var_assignments);
         if !self.ctx.check_cancel() {
+            if do_file != DoFile::Only {
+                self.complete_abbr(current_argument, false);
+            }
+
             // This function wants the unescaped string.
             self.complete_param_expand(
                 current_argument,
-                do_file,
+                do_file != DoFile::No,
                 handle_as_special_cd,
                 cur_tok.is_unterminated_brace,
             );
@@ -1144,15 +1159,18 @@ fn complete_cmd(&mut self, str_cmd: WString) {
         }
     }
 
-    /// Attempt to complete an abbreviation for the given string.
-    fn complete_abbr(&mut self, cmd: &wstr) {
+    /// Attempt to complete a non-regex abbreviation for the given string.
+    fn complete_abbr(&mut self, cmd: &wstr, is_command_position: bool) {
         // Copy the list of names and descriptions so as not to hold the lock across the call to
         // complete_strings.
         let mut possible_comp = Vec::new();
         let mut descs = HashMap::new();
         with_abbrs(|set| {
             for abbr in set.list() {
-                if !abbr.is_regex() {
+                if abbr.is_regex() {
+                    continue;
+                }
+                if abbr.position == Position::Anywhere || is_command_position {
                     possible_comp.push(Completion::from_completion(abbr.key.clone()));
                     descs.insert(abbr.key.clone(), abbr.replacement.clone());
                 }

tests/checks/complete.fish

@@ -645,6 +645,22 @@ abbr cat cat
 complete -C ca | string match -r '^cat(?:\t.*)?$'
 # CHECK: cat{{\t}}Abbreviation: cat
 
+# anywhere-position abbrs complete in non-command position
+abbr --position anywhere __test_pgr '| grep -i'
+complete -C'echo __test_pgr' | string match -r '^__test_pgr.*'
+# CHECK: __test_pgr{{\t}}Abbreviation: | grep -i
+
+# anywhere-position abbrs still complete in command position (regression guard)
+complete -C__test_pgr | string match -r '^__test_pgr.*'
+# CHECK: __test_pgr{{\t}}Abbreviation: | grep -i
+
+# command-position-only abbrs do NOT complete in non-command position
+abbr --position command __test_cmd_only 'git status'
+complete -C'echo __test_cmd' | string match -rq '^__test_cmd'
+echo $status
+# CHECK: 1
+abbr --erase __test_pgr __test_cmd_only
+
 complete complete-list -xa '(__fish_complete_list , "seq 2")'
 complete -C "complete-list 1,"
 # CHECK: 1,1