Revert "completions/git: cache subcommand computation"

Commit ad9b4290e optimized git completions by adding a completion that would
run on every completion request, which allows to precompute data used by
other completion entries. Unfortunately, the completion entry is not run
when the commandline contains a flag like `git -C`. If we didn't
already load git.fish, we'd error. Additionally, we got false positive
completions for `git diff -c`.

So this hack was a very bad idea. We should optimize in another way.

CHANGELOG.rst

@@ -26,6 +26,7 @@ Improved prompts
 Completions
 ^^^^^^^^^^^
 - Added completions for:
+- A regression in 3.5.0 caused completions for ``git -C`` to print errors, which has been fixed.
 
 
 Improved terminal support

share/completions/git.fish

@@ -563,6 +563,25 @@ function __fish_git_ranges
     end
 end
 
+function __fish_git_needs_command
+    # Figure out if the current invocation already has a command.
+    set -l cmd (commandline -opc)
+    set -e cmd[1]
+    argparse -s (__fish_git_global_optspecs) -- $cmd 2>/dev/null
+    or return 0
+    # These flags function as commands, effectively.
+    set -q _flag_version; and return 1
+    set -q _flag_html_path; and return 1
+    set -q _flag_man_path; and return 1
+    set -q _flag_info_path; and return 1
+    if set -q argv[1]
+        # Also print the command, so this can be used to figure out what it is.
+        echo $argv[1]
+        return 1
+    end
+    return 0
+end
+
 function __fish_git_config_keys
     # Print already defined config values first
     # Config keys may span multiple lines, so parse using null char
@@ -614,12 +633,19 @@ git config -z --get-regexp 'alias\..*' | while read -lz alias cmdline
     set -g __fish_git_alias_$alias $command $cmdline
 end
 
-function __fish_git_needs_command
-    $__fish_git_needs_command
-end
-
 function __fish_git_using_command
-    contains $__fish_git_subcommand $argv
+    set -l cmd (__fish_git_needs_command)
+    test -z "$cmd"
+    and return 1
+    contains -- $cmd $argv
+    and return 0
+
+    # Check aliases.
+    set -l varname __fish_git_alias_(string escape --style=var -- $cmd)
+    set -q $varname
+    and contains -- $$varname[1][1] $argv
+    and return 0
+    return 1
 end
 
 function __fish_git_contains_opt
@@ -630,8 +656,10 @@ function __fish_git_contains_opt
 
     # Now check the alias
     argparse s= -- $argv
-    if set -q __fish_git_expanded_alias[1]
-        echo -- $__fish_git_expanded_alias | read -lat toks
+    set -l cmd (__fish_git_needs_command)
+    set -l varname __fish_git_alias_(string escape --style=var -- $cmd)
+    if set -q $varname
+        echo -- $$varname | read -lat toks
         set toks (string replace -r '(-.*)=.*' '' -- $toks)
         for i in $argv
             if contains -- --$i $toks
@@ -2267,29 +2295,3 @@ for file in $PATH/git-*
     complete -c git -f -n "__fish_git_using_command $subcommand" -a "(__fish_git_complete_custom_command $subcommand)"
     set -a __fish_git_custom_commands_completion $subcommand
 end
-
-complete -c git -f -a '(
-    set -g __fish_git_needs_command true
-    set -g __fish_git_subcommand ""
-    set -g __fish_git_expanded_alias
-
-    set -l cmd (commandline -opc)
-    set -e cmd[1]
-    argparse -s (__fish_git_global_optspecs) -- $cmd 2>/dev/null
-    or return
-
-    if set -q argv[1] || set -q _flag_version || set -q _flag_html_path || set -q _flag_man_path || set -q _flag_info_path
-        set __fish_git_needs_command false
-    end
-
-    if set -q argv[1]
-        set -l subcommand $argv[1]
-        # TODO Expand recursive aliases.
-        set -l varname __fish_git_alias_(string escape --style=var -- $subcommand)
-        if set -q $varname
-            set -g __fish_git_expanded_alias $$varname
-            set subcommand $__fish_git_expanded_alias[1]
-        end
-        set -g __fish_git_subcommand "$subcommand"
-    end
-)'

tests/checks/git.fish

@@ -3,6 +3,8 @@
 # e.g. the fish_git_prompt variable handlers test `status is-interactive`.
 #REQUIRES: command -v git
 
+set -g fish (status fish-path)
+
 # Tests run from git (e.g. git rebase --exec 'ninja test'...) inherit a weird git environment.
 # Ensure that no git environment variables are inherited.
 for varname in (set -x | string match 'GIT_*' | string replace -r ' .*' '')
@@ -134,3 +136,6 @@ test "$(complete -C'git re ')" = "$(complete -C'git restore --staged ')"
 or begin
     echo -- Oops re completes unlike restore --staged
 end
+
+$fish -c 'complete -C "git -C ./.gi"'
+# CHECK: ./.git/	Directory