Always return absolute path in path_get_cdpath

Fixes #6220

CHANGELOG.md

@@ -19,6 +19,7 @@
 - The null command (`:`) now always exits successfully, rather than passing through the previous exit status (#6022).
 - `jobs --last` returns 0 to indicate success when a job is found (#6104).
 - `commandline -p` and `commandline -j` now split on `&&` and `||` in addition to `;` and `&` (#6214)
+- `fish` now correctly handles CDPATH entries that starts with `..` (#6220)
 
 ### Syntax changes and new commands
 - Brace expansion now only takes place if the braces include a "," or a variable expansion, meaning common commands such as `git reset HEAD@{0}` do not require escaping (#5869).

src/path.cpp

@@ -161,8 +161,7 @@ maybe_t<wcstring> path_get_cdpath(const wcstring &dir, const wcstring &wd,
                                   const environment_t &env_vars) {
     int err = ENOENT;
     if (dir.empty()) return none();
-
-    assert(wd.empty() || wd.back() == L'/');
+    assert(!wd.empty() && wd.back() == L'/');
     wcstring_list_t paths;
     if (dir.at(0) == L'/') {
         // Absolute path.
@@ -181,14 +180,16 @@ maybe_t<wcstring> path_get_cdpath(const wcstring &dir, const wcstring &wd,
         cdpathsv.push_back(L".");
         for (wcstring next_path : cdpathsv) {
             if (next_path.empty()) next_path = L".";
-            if (next_path == L"." && !wd.empty()) {
+            if (next_path == L".") {
                 // next_path is just '.', and we have a working directory, so use the wd instead.
                 next_path = wd;
             }
 
-            // If next_path starts with ./ we need to replace the . with the wd.
-            if (string_prefixes_string(L"./", next_path) && !wd.empty()) {
+            // We want to return an absolute path (see issue 6220)
+            if (string_prefixes_string(L"./", next_path)) {
                 next_path = next_path.replace(0, 2, wd);
+            } else if (string_prefixes_string(L"../", next_path) || next_path == L"..") {
+                next_path = next_path.insert(0, wd);
             }
 
             expand_tilde(next_path, env_vars);

src/path.h

@@ -58,8 +58,7 @@ wcstring_list_t path_get_paths(const wcstring &cmd, const environment_t &vars);
 /// are found, it is undefined which error status will be returned.
 ///
 /// \param dir The name of the directory.
-/// \param out_or_NULL If non-NULL, return the path to the resolved directory
-/// \param wd The working directory. The working directory should have a slash appended at the end.
+/// \param wd The working directory. The working directory must end with a slash.
 /// \param vars The environment variables to use (for the CDPATH variable)
 /// \return the command, or none() if it could not be found.
 maybe_t<wcstring> path_get_cdpath(const wcstring &dir, const wcstring &wd,

tests/checks/cd.fish

@@ -0,0 +1,13 @@
+# RUN: %fish %s
+set -l tmp (mktemp -d)
+cd $tmp
+# resolve CDPATH (issue 6220)
+begin
+    mkdir -p x
+    # CHECK: /{{.*}}/x
+    cd x; pwd
+
+    # CHECK: /{{.*}}/x
+    set -lx CDPATH ..; cd x; pwd
+end
+rm -rf $tmp