fix(complete): make git diff log <TAB> Bash-complete for git diff

This continues the work started with the fix for clap-rs#4273. There was
another bug caused by using the subcommand names without considering
their position in the argument list. If the user enters `git diff log
<TAB>`, we build up a string that identifies the subcommand. We ended
up making the string `git__diff__log` in this case because we appended
`__log` without considering the current state. Since `git__diff__log`
does not correspond to an actual command, we wouldn't provide any
suggestions.

This commit restructures the code so we walk subcommands and
subsubcommands in `bash.rs`. While walking those, we build up a list
containing triples of the parent `$cmd` name (e.g. `git__diff`), the
current command's name (e.g. `log`), and the `$cmd` for the current
command. We then build the shell script's case arms based on that
information.

We could instead have fixed clap-rs#4280 by using the second element in the
pair returned from `utils::all_subcommands()` (a stringified list of
the subcommand path) instead of the first one. However, that would not
have helped us solve clap-rs#4265.

Closes clap-rs#4280

clap_complete/src/shells/bash.rs

@@ -75,26 +75,45 @@ complete -F _{name} -o bashdefault -o default {name}
 fn all_subcommands(cmd: &Command) -> String {
     debug!("all_subcommands");
 
-    let mut subcmds = vec![String::new()];
-    let mut scs = utils::all_subcommands(cmd)
-        .iter()
-        .map(|x| x.0.clone())
-        .collect::<Vec<_>>();
-
-    scs.sort();
-    scs.dedup();
+    fn add_command(
+        parent_fn_name: &str,
+        cmd: &Command,
+        subcmds: &mut Vec<(String, String, String)>,
+    ) {
+        let fn_name = format!(
+            "{parent_fn_name}__{cmd_name}",
+            parent_fn_name = parent_fn_name,
+            cmd_name = cmd.get_name().to_string().replace('-', "__")
+        );
+        subcmds.push((
+            parent_fn_name.to_string(),
+            cmd.get_name().to_string(),
+            fn_name.clone(),
+        ));
+        for subcmd in cmd.get_subcommands() {
+            add_command(&fn_name, subcmd, subcmds);
+        }
+    }
+    let mut subcmds = vec![];
+    let fn_name = cmd.get_name().replace('-', "__");
+    for subcmd in cmd.get_subcommands() {
+        add_command(&fn_name, subcmd, &mut subcmds);
+    }
+    subcmds.sort();
 
-    subcmds.extend(scs.iter().map(|sc| {
-        format!(
-            "*,{name})
-                cmd+=\"__{fn_name}\"
+    let mut cases = vec![String::new()];
+    for (parent_fn_name, name, fn_name) in subcmds {
+        cases.push(format!(
+            "{parent_fn_name},{name})
+                cmd=\"{fn_name}\"
                 ;;",
-            name = sc,
-            fn_name = sc.replace('-', "__")
-        )
-    }));
+            parent_fn_name = parent_fn_name,
+            name = name,
+            fn_name = fn_name,
+        ));
+    }
 
-    subcmds.join("\n            ")
+    cases.join("\n            ")
 }
 
 fn subcommand_details(cmd: &Command) -> String {

clap_complete/tests/snapshots/basic.bash

@@ -12,11 +12,11 @@ _my-app() {
             ",$1")
                 cmd="my__app"
                 ;;
-            *,help)
-                cmd+="__help"
+            my__app,help)
+                cmd="my__app__help"
                 ;;
-            *,test)
-                cmd+="__test"
+            my__app,test)
+                cmd="my__app__test"
                 ;;
             *)
                 ;;

clap_complete/tests/snapshots/feature_sample.bash

@@ -12,11 +12,11 @@ _my-app() {
             ",$1")
                 cmd="my__app"
                 ;;
-            *,help)
-                cmd+="__help"
+            my__app,help)
+                cmd="my__app__help"
                 ;;
-            *,test)
-                cmd+="__test"
+            my__app,test)
+                cmd="my__app__test"
                 ;;
             *)
                 ;;

clap_complete/tests/snapshots/quoting.bash

@@ -12,26 +12,26 @@ _my-app() {
             ",$1")
                 cmd="my__app"
                 ;;
-            *,cmd-backslash)
-                cmd+="__cmd__backslash"
+            my__app,cmd-backslash)
+                cmd="my__app__cmd__backslash"
                 ;;
-            *,cmd-backticks)
-                cmd+="__cmd__backticks"
+            my__app,cmd-backticks)
+                cmd="my__app__cmd__backticks"
                 ;;
-            *,cmd-brackets)
-                cmd+="__cmd__brackets"
+            my__app,cmd-brackets)
+                cmd="my__app__cmd__brackets"
                 ;;
-            *,cmd-double-quotes)
-                cmd+="__cmd__double__quotes"
+            my__app,cmd-double-quotes)
+                cmd="my__app__cmd__double__quotes"
                 ;;
-            *,cmd-expansions)
-                cmd+="__cmd__expansions"
+            my__app,cmd-expansions)
+                cmd="my__app__cmd__expansions"
                 ;;
-            *,cmd-single-quotes)
-                cmd+="__cmd__single__quotes"
+            my__app,cmd-single-quotes)
+                cmd="my__app__cmd__single__quotes"
                 ;;
-            *,help)
-                cmd+="__help"
+            my__app,help)
+                cmd="my__app__help"
                 ;;
             *)
                 ;;

clap_complete/tests/snapshots/special_commands.bash

@@ -12,20 +12,20 @@ _my-app() {
             ",$1")
                 cmd="my__app"
                 ;;
-            *,help)
-                cmd+="__help"
+            my__app,help)
+                cmd="my__app__help"
                 ;;
-            *,some-cmd-with-hyphens)
-                cmd+="__some__cmd__with__hyphens"
+            my__app,some-cmd-with-hyphens)
+                cmd="my__app__some__cmd__with__hyphens"
                 ;;
-            *,some-hidden-cmd)
-                cmd+="__some__hidden__cmd"
+            my__app,some-hidden-cmd)
+                cmd="my__app__some__hidden__cmd"
                 ;;
-            *,some_cmd)
-                cmd+="__some_cmd"
+            my__app,some_cmd)
+                cmd="my__app__some_cmd"
                 ;;
-            *,test)
-                cmd+="__test"
+            my__app,test)
+                cmd="my__app__test"
                 ;;
             *)
                 ;;

clap_complete/tests/snapshots/sub_subcommands.bash

@@ -12,17 +12,20 @@ _my-app() {
             ",$1")
                 cmd="my__app"
                 ;;
-            *,help)
-                cmd+="__help"
+            my__app,help)
+                cmd="my__app__help"
                 ;;
-            *,some_cmd)
-                cmd+="__some_cmd"
+            my__app,some_cmd)
+                cmd="my__app__some_cmd"
                 ;;
-            *,sub_cmd)
-                cmd+="__sub_cmd"
+            my__app,test)
+                cmd="my__app__test"
                 ;;
-            *,test)
-                cmd+="__test"
+            my__app__some_cmd,help)
+                cmd="my__app__some_cmd__help"
+                ;;
+            my__app__some_cmd,sub_cmd)
+                cmd="my__app__some_cmd__sub_cmd"
                 ;;
             *)
                 ;;