Keep completion words out of shell evaluation

internal/cobra/completion.go

@@ -96,6 +96,46 @@ func CompletionScript(w io.Writer, executable, shell string) error {
 
 func adjustBashCompletion(script, name string) (string, error) {
 	var err error
+	script, err = replaceCompletionSection(script, "    local requestComp lastParam lastChar args", "    # Extract the directive", `    local -a requestWords=()
+    local word char quote decoded next i backtick=$'\x60'
+    # Bash's completion helpers supply shell spelling, not evaluated argv.
+    # Remove quoting and escapes without expanding substitutions or globs.
+    for word in "${words[@]}"; do
+        quote=
+        decoded=
+        for ((i=0; i<${#word}; i++)); do
+            char=${word:i:1}
+            case "$quote:$char" in
+                "':'"|'":"') quote= ;;
+                ':"'|":'") quote=$char ;;
+                :\\|'"':\\)
+                    if ((i+1 < ${#word})); then
+                        next=${word:i+1:1}
+                        if [[ $quote == '"' && $next != '\' && $next != '"' && $next != '$' && $next != "$backtick" ]]; then
+                            decoded+=$char
+                            continue
+                        fi
+                        ((i+=1))
+                        decoded+=${word:i:1}
+                    else
+                        decoded+=$char
+                    fi ;;
+                *) decoded+=$char ;;
+            esac
+        done
+        requestWords+=("$decoded")
+    done
+    if [[ -z $cur && ${words[${#words[@]}-1]} != *= ]]; then
+        # The Bash helpers may omit the empty word at a trailing space.
+        if ((${#requestWords[@]} <= cword)); then requestWords+=(""); fi
+    fi
+    if [[ ${cur} == -*=* ]]; then cur="${cur#*=}"; fi
+    out=$(COBRA_ACTIVE_HELP=0 "${requestWords[0]}" __complete "${requestWords[@]:1}" 2>/dev/null)
+
+`)
+	if err != nil {
+		return "", err
+	}
 	script, err = replaceCompletionText(script, `local out directive`, `local out directive completionPrefix completionOriginalCur`)
 	if err != nil {
 		return "", err
@@ -145,29 +185,68 @@ func adjustBashCompletion(script, name string) (string, error) {
 
 func adjustZshCompletion(script string) (string, error) {
 	var err error
-	script, err = replaceCompletionText(script, `words=("${=words[1,CURRENT]}")`, `words=("${(@)words[1,CURRENT]}")`)
+	script, err = replaceCompletionText(script, `words=("${=words[1,CURRENT]}")`, `words=("${(@Q)words[1,CURRENT]}")`)
 	if err != nil {
 		return "", err
 	}
-	script, err = replaceCompletionText(script, `=~ '-.*='`, `=~ '-[^=]*='`)
+	script, err = replaceCompletionSection(script, "    # For zsh, when completing a flag", "    # Extract the directive", `    local -a prefixArgs orderArgs spaceArgs
+    if [[ "$lastParam" == -*=* ]]; then
+        flagPrefix="${lastParam%%=*}="
+    fi
+    out=$(COBRA_ACTIVE_HELP=0 "${words[1]}" __complete "${words[@]:1}" 2>/dev/null)
+
+`)
 	if err != nil {
 		return "", err
 	}
-	return replaceCompletionText(script, `local activeHelpMarker="_activeHelp_ "`, `if [[ "$out" == `+completionPathPrefixMarker+`-* ]]; then
+	script, err = replaceCompletionText(script, `local activeHelpMarker="_activeHelp_ "`, `if [[ "$out" == `+completionPathPrefixMarker+`-* ]]; then
         local pathPrefix="${out%%$'\n'*}"
         pathPrefix="${pathPrefix#`+completionPathPrefixMarker+`}"
         if [[ "$pathPrefix" != --* && "$lastParam" == "$pathPrefix"* ]]; then
             out="${out#*$'\n'}"
-            if [ $((directive & shellCompDirectiveNoFileComp)) -ne 0 ]; then
-                flagPrefix="-P ${pathPrefix}"
-            else
-                flagPrefix=""
-                compset -P "${(b)pathPrefix}"
-            fi
+            flagPrefix="$pathPrefix"
         fi
     fi
+    if [[ -n "$flagPrefix" ]]; then
+        prefixArgs=(-P "$flagPrefix")
+    fi
 
     local activeHelpMarker="_activeHelp_ "`)
+	if err != nil {
+		return "", err
+	}
+	return replaceCompletionSection(script, "    if [ $((directive & shellCompDirectiveNoSpace))", "\n}\n", `    if [ $((directive & shellCompDirectiveNoSpace)) -ne 0 ]; then
+        spaceArgs=(-S "")
+    fi
+    if [ $((directive & shellCompDirectiveKeepOrder)) -ne 0 ]; then
+        orderArgs=(-V)
+    fi
+
+    if [ $((directive & shellCompDirectiveNoFileComp)) -ne 0 ]; then
+        _describe "${orderArgs[@]}" completions completions "${prefixArgs[@]}" "${spaceArgs[@]}"
+    else
+        if [[ -n "$flagPrefix" ]]; then
+            compset -P "${(b)flagPrefix}"
+        fi
+        if [ $((directive & shellCompDirectiveFilterDirs)) -ne 0 ]; then
+            _files -/
+        else
+            _files
+        fi
+    fi
+`)
+}
+
+func replaceCompletionSection(script, start, end, replacement string) (string, error) {
+	i := strings.Index(script, start)
+	if i < 0 {
+		return "", fmt.Errorf("unsupported generated completion script")
+	}
+	j := strings.Index(script[i+len(start):], end)
+	if j < 0 {
+		return "", fmt.Errorf("unsupported generated completion script")
+	}
+	return script[:i] + replacement + script[i+len(start)+j:], nil
 }
 
 func replaceCompletionText(script, old, replacement string) (string, error) {

internal/cobra/completion_test.go

@@ -161,6 +161,32 @@ sys.stdout.write(os.environ['PROBE_REPLY'])
 				}
 			})
 		}
+		if shell == "bash" || shell == "zsh" {
+			for _, tc := range []struct{ name, line string }{
+				{"quoted", `probe --format '-$(touch sentinel)=x'`},
+				{"escaped", `probe --format -\$\(touch\ sentinel\)=x`},
+			} {
+				t.Run(shell+"/literal query/"+tc.name, func(t *testing.T) {
+					log := filepath.Join(dir, "query-log")
+					if err := os.WriteFile(log, nil, 0o600); err != nil {
+						t.Fatal(err)
+					}
+					cmd := exec.Command("python3", "testdata/completion_terminal.py", shell, script, tc.line)
+					cmd.Env = append(os.Environ(), "PATH="+dir+string(os.PathListSeparator)+os.Getenv("PATH"), "HOME="+dir, "TERM=xterm", "PROBE_DIR="+dir, "PROBE_LOG="+log, "PROBE_TAB_ONLY=1", "PROBE_REPLY=:4\n")
+					if out, err := cmd.CombinedOutput(); err != nil {
+						t.Fatalf("tab-only completion: %v\n%s", err, out)
+					}
+					if _, err := os.Stat(filepath.Join(dir, "sentinel")); !os.IsNotExist(err) {
+						t.Fatalf("completion executed literal input: %v", err)
+					}
+					got, err := os.ReadFile(log)
+					if err != nil || !strings.Contains(string(got), `["__complete", "--format", "-$(touch sentinel)=x"]`) {
+						t.Fatalf("literal query was not preserved: %q, %v", got, err)
+					}
+				})
+			}
+		}
+
 		for _, executable := range []string{"probe.app", "café"} {
 			t.Run(shell+"/executable "+executable, func(t *testing.T) {
 				var generated bytes.Buffer

internal/cobra/testdata/completion_terminal.py

@@ -30,6 +30,15 @@ elif shell == "fish":
 else:
     raise SystemExit(f"unsupported shell: {shell}")
 
+tab_only = os.environ.get("PROBE_TAB_ONLY") == "1"
+if tab_only:
+    if shell == "zsh":
+        setup += "; function ck_tab_done { print CK_TAB_FINISHED; }; zle -N ck_tab_done; bindkey '^X^T' ck_tab_done"
+    elif shell == "bash":
+        setup += r"""; bind -x '"\C-x\C-t": "printf CK_TAB_FINISHED"'"""
+    else:
+        raise SystemExit("tab-only probe requires Bash or Zsh")
+
 child = pexpect.spawn(executable, args, env=os.environ.copy(), cwd=os.environ["PROBE_DIR"],
                       encoding="utf-8", timeout=15, dimensions=(24, 120))
 child.delaybeforesend = 0.05
@@ -39,7 +48,11 @@ try:
     child.expect_exact("PROMPT> ")
     child.send(line)
     child.send("\t")
-    if os.environ.get("PROBE_LIST") == "1":
+    if tab_only:
+        child.sendcontrol("x")
+        child.sendcontrol("t")
+        child.expect_exact("CK_TAB_FINISHED")
+    elif os.environ.get("PROBE_LIST") == "1":
         child.send("\t")
         remaining = ["Readable text", "YAML output"]
         captured = []