Preemptively unset WAYLAND_DISPLAY

src/common/process.cpp

@@ -174,6 +174,13 @@ void ProcessEnvironment::insert(const std::string& key,
     variables_.push_back(key + "=" + value);
 }
 
+size_t ProcessEnvironment::erase(const std::string& key) {
+    return std::erase_if(variables_, [&key](const std::string& variable) {
+        return variable.starts_with(key) && variable.size() > key.size() &&
+               variable[key.size()] == '=';
+    });
+}
+
 char* const* ProcessEnvironment::make_environ() const {
     recreated_environ_.clear();
 

src/common/process.h

@@ -101,6 +101,14 @@ class ProcessEnvironment {
      */
     void insert(const std::string& key, const std::string& value);
 
+    /**
+     * Remove an environment variable from the environment. Returns the number
+     * of elements erased (to stay consistent with the STL map interface). This
+     * can be higher than 1 if the map contains duplicate or overwritten
+     * environment variables.
+     */
+    size_t erase(const std::string& key);
+
     /**
      * Create an environ-like object from the updated environment that can be
      * passed to the `exec*e()` functions. These pointers will be invalidated