fix(complete): Trailing space after zsh directory completions

zsh dynamic completions would add a trailing space after all
completions, including directories. This prevented natural path
completion. Users had to delete the trailing space before continuing to
type or tab-complete within the directory.

The fix is for the dynamic completion script to separate completions
into directories and non-directories, and providing the directory
completions to zsh with a different _describe invocation.

For directories:
1. Strip the trailing slash from the completion value
2. Let zsh add it back as a suffix using `_describe -S '/'`
3. Also provide `-r '/'` to make the slash auto-removable when typing '/'

This makes dynamic path completions reasonably emulate zsh-native file
completions.

This matches the behavior already implemented for bash completions which
uses 'compopt -o nospace' to achieve the same result.

Fixes: #6178
Ref: jj-vcs/jj#5582

Author: jpgrayson

clap_complete/src/env/shells.rs

@@ -381,7 +381,25 @@ function _clap_dynamic_completer_NAME() {
     )}")
 
     if [[ -n $completions ]]; then
-        _describe 'values' completions
+        local -a dirs=()
+        local -a other=()
+        local completion
+        for completion in $completions; do
+            local value="${completion%%:*}"
+            if [[ "$value" == */ ]]; then
+                local dir_no_slash="${value%/}"
+                if [[ "$completion" == *:* ]]; then
+                    local desc="${completion#*:}"
+                    dirs+=("$dir_no_slash:$desc")
+                else
+                    dirs+=("$dir_no_slash")
+                fi
+            else
+                other+=("$completion")
+            fi
+        done
+        [[ -n $dirs ]] && _describe 'values' dirs -S '/' -r '/'
+        [[ -n $other ]] && _describe 'values' other
     fi
 }
 

clap_complete/tests/snapshots/home/dynamic-env/exhaustive/zsh/zsh/_exhaustive

@@ -11,7 +11,25 @@ function _clap_dynamic_completer_exhaustive() {
     )}")
 
     if [[ -n $completions ]]; then
-        _describe 'values' completions
+        local -a dirs=()
+        local -a other=()
+        local completion
+        for completion in $completions; do
+            local value="${completion%%:*}"
+            if [[ "$value" == */ ]]; then
+                local dir_no_slash="${value%/}"
+                if [[ "$completion" == *:* ]]; then
+                    local desc="${completion#*:}"
+                    dirs+=("$dir_no_slash:$desc")
+                else
+                    dirs+=("$dir_no_slash")
+                fi
+            else
+                other+=("$completion")
+            fi
+        done
+        [[ -n $dirs ]] && _describe 'values' dirs -S '/' -r '/'
+        [[ -n $other ]] && _describe 'values' other
     fi
 }
 

clap_complete/tests/testsuite/zsh.rs

@@ -370,3 +370,32 @@ help                                -- Print this message or the help of the giv
     let actual = runtime.complete(input, &term).unwrap();
     assert_data_eq!(actual, expected);
 }
+
+#[test]
+#[cfg(all(unix, feature = "unstable-dynamic"))]
+#[cfg(feature = "unstable-shell-tests")]
+fn complete_dynamic_dir_no_trailing_space() {
+    if !common::has_command(CMD) {
+        return;
+    }
+
+    let term = completest::Term::new();
+    let mut runtime = common::load_runtime::<RuntimeBuilder>("dynamic-env", "exhaustive");
+
+    // First, complete to the directory name with slash.
+    // A trailing slash should not be added after the slash.
+    let input = "exhaustive hint --file tes\t\t";
+    let expected = snapbox::str!["% exhaustive hint --file tests/"];
+    let actual = runtime.complete(input, &term).unwrap();
+    assert_data_eq!(actual, expected);
+
+    // Verify hitting tab again shows the directory contents.
+    // This only works if there is no trailing space after the slash.
+    let input = "exhaustive hint --file tests/\t\t";
+    let expected = snapbox::str![[r#"
+% exhaustive hint --file tests/
+tests/examples.rs  tests/snapshots    tests/testsuite
+"#]];
+    let actual = runtime.complete(input, &term).unwrap();
+    assert_data_eq!(actual, expected);
+}