[FIX] Fix startup in non existing directory

[itislu]

Test case:

mkdir -p /tmp/dir && cd /tmp/dir && rm -rf ../dir
<absolute path to minishell>

• Fix leak:
  
• Don't exit (follows the behavior of bash).
• Usually, bash always sets the PWD env variable itself and overwrites any exported value on startup. However, if it cannot get the cwd then it keeps the existing value, if one exists.
• Print an error:
  

[itislu]

• First merge [LIB] Add new linked list functions to libft #341 (this PR uses one of the new linked list functions)

[itislu]

This caused the leak when starting in a non-existing directory.
check_special_env_vars() sets the PWD environment variable, and if getcwd() fails it returns false.
This issue existed even in the evaluation version.

[itislu]

Moved env setup (which allocates memory and can print errors) after setting up the signal handlers so memory can be freed when a signal gets received.

Test case with SIGPIPE:

(rm -f /tmp/valgrind.log ; valgrind --log-file=/tmp/valgrind.log --leak-check=full --show-leak-kinds=all <absolute_path_to_minishell> 2>&1 | exit)
cat /tmp/valgrind.log

[Copilot]

Pull Request Overview

Fix shell startup behavior when running in a non‐existent directory by handling PWD/OLDPWD initialization more robustly, preventing premature exit and leaks, and reporting errors like Bash.

• Reordered setup_env_list in init_shell to avoid early return before signal setup.
• Refactored environment list setup to handle special variables (PWD, OLDPWD) via handle_pwd and handle_oldpwd helpers.
• Enhanced default PWD initialization to report getcwd errors (excluding ENOMEM) without exiting.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
source/shell/init.c	Moved setup_env_list after signal registrations.
source/shell/env_list.c	Added tail pointer, check_special_env_vars, and handlers for PWD/OLDPWD.
source/shell/default_env_list.c	Improved add_default_pwd_env_node to log getcwd errors gracefully.
source/backend/builtins/cd/path.c	Renamed pwd variables to cwd and updated file header.
source/backend/builtins/cd/env_pwd_update.c	Updated file name in header comment.
source/backend/builtins/cd/dot_components.c	Updated file name in header comment.
source/backend/builtins/cd/component_list_utils.c	Updated file name in header comment.
source/backend/builtins/cd/component_list.c	Updated file name in header comment and prototype rename.
include/cd.h	Updated prototypes and header grouping to reflect renames.
build/source_files.mk	Renamed dot_component.c to dot_components.c in build list.

Comments suppressed due to low confidence (3)

source/shell/env_list.c:16

• [nitpick] The parameter name env_node in check_special_env_vars is ambiguous; consider renaming to env_list_node or similar to clarify that it refers to a single list node.

static bool	check_special_env_vars(t_list **env_node);

source/shell/default_env_list.c:57

• Handling of getcwd failures (ENOMEM vs other errors) in add_default_pwd_env_node introduces new error-reporting branches; consider adding unit tests for PWD initialization when getcwd fails to validate behavior.

	if (!value)

source/shell/env_list.c:92

• ft_lstdrop_node is called with the same pointer for both head pointer and node-to-drop; verify the function signature and ensure you pass the correct head pointer and node arguments to avoid removing the wrong element.

		ft_lstdrop_node(env_node, env_node, (void *)free_env_node);