Implement startup configuration file support (issue #08)

Load ~/.config/lush/config and config.d/*.lua at REPL startup,
respecting XDG_CONFIG_HOME. Suppressed by -E flag.

issues/08-configuration.md

@@ -1,6 +1,6 @@
 # 08 — Configuration support
 
-**Status:** open
+**Status:** done
 
 Users should be able to programmatically configure the shell at startup.
 

lua.c

@@ -13,6 +13,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <dirent.h>
+#include <limits.h>
 #include <signal.h>
 
 #include "lua.h"
@@ -722,6 +724,79 @@ static void doREPL (lua_State *L) {
 #endif
 
 
+/*
+** {==================================================================
+** Configuration file support
+** ===================================================================
+*/
+
+static const char *get_config_dir (char *buf, size_t bufsize) {
+  const char *xdg = getenv("XDG_CONFIG_HOME");
+  const char *home = getenv("HOME");
+  if (xdg && xdg[0] != '\0')
+    snprintf(buf, bufsize, "%s/lush", xdg);
+  else if (home && home[0] != '\0')
+    snprintf(buf, bufsize, "%s/.config/lush", home);
+  else
+    return NULL;
+  return buf;
+}
+
+
+static int cmpstr (const void *a, const void *b) {
+  return strcmp(*(const char **)a, *(const char **)b);
+}
+
+
+static void run_config_dir (lua_State *L, const char *dirpath) {
+  char *names[256];
+  int count = 0;
+  int i;
+  struct dirent *entry;
+  DIR *d = opendir(dirpath);
+  if (d == NULL) return;  /* directory doesn't exist — skip silently */
+
+  /* collect .lua filenames */
+  while ((entry = readdir(d)) != NULL && count < 256) {
+    size_t len = strlen(entry->d_name);
+    if (len > 4 && strcmp(entry->d_name + len - 4, ".lua") == 0)
+      names[count++] = strdup(entry->d_name);
+  }
+  closedir(d);
+
+  /* sort lexicographically */
+  qsort(names, (size_t)count, sizeof(char *), cmpstr);
+
+  /* execute each file */
+  for (i = 0; i < count; i++) {
+    char path[PATH_MAX];
+    snprintf(path, sizeof(path), "%s/%s", dirpath, names[i]);
+    dofile(L, path);  /* errors reported but not fatal */
+    free(names[i]);
+  }
+}
+
+
+static void handle_lushconfig (lua_State *L) {
+  char configdir[PATH_MAX];
+  char path[PATH_MAX];
+
+  if (get_config_dir(configdir, sizeof(configdir)) == NULL)
+    return;  /* no HOME or XDG_CONFIG_HOME — skip silently */
+
+  /* 1. Run ~/.config/lush/config if it exists */
+  snprintf(path, sizeof(path), "%s/config", configdir);
+  if (access(path, R_OK) == 0)
+    dofile(L, path);  /* errors are reported but not fatal */
+
+  /* 2. Run config.d/ lua files in sorted order */
+  snprintf(path, sizeof(path), "%s/config.d", configdir);
+  run_config_dir(L, path);
+}
+
+/* }================================================================== */
+
+
 /*
 ** Main body of stand-alone interpreter (to be called in protected mode).
 ** Reads the options and handles them all.
@@ -757,11 +832,16 @@ static int pmain (lua_State *L) {
     if (handle_script(L, argv + script) != LUA_OK)
       return 0;  /* interrupt in case of error */
   }
-  if (args & has_i)  /* -i option? */
+  if (args & has_i) {  /* -i option? */
+    if (!(args & has_E))
+      handle_lushconfig(L);
     doREPL(L);  /* do read-eval-print loop */
+  }
   else if (script < 1 && !(args & (has_e | has_v))) { /* no active option? */
     if (lua_stdin_is_tty()) {  /* running in interactive mode? */
       print_version();
+      if (!(args & has_E))
+        handle_lushconfig(L);
       doREPL(L);  /* do read-eval-print loop */
     }
     else dofile(L, NULL);  /* executes stdin as a file */

testes/lush/config.lua

@@ -0,0 +1,151 @@
+-- testes/lush/config.lua
+-- Tests for configuration file support (issue #08).
+
+print "testing configuration"
+
+-- helper: get a unique temp directory
+local tmpbase = os.tmpname()
+os.remove(tmpbase)  -- tmpname creates the file on some systems
+
+local function mkdir(path)
+  os.execute('mkdir -p "' .. path .. '"')
+end
+
+local function writefile(path, content)
+  local f = assert(io.open(path, "w"))
+  f:write(content)
+  f:close()
+end
+
+local function rmrf(path)
+  os.execute('rm -rf "' .. path .. '"')
+end
+
+-- helper: run ./lua -i with XDG_CONFIG_HOME set, feed it a command via stdin
+local function run_with_config(xdg_dir, input)
+  local cmd = string.format(
+    'printf "%%s\\n" "%s" | XDG_CONFIG_HOME="%s" ./lua -i 2>&1',
+    input, xdg_dir)
+  local f = io.popen(cmd)
+  local output = f:read("*a")
+  f:close()
+  return output
+end
+
+-- helper: run ./lua -E -i with XDG_CONFIG_HOME set
+local function run_with_config_E(xdg_dir, input)
+  local cmd = string.format(
+    'printf "%%s\\n" "%s" | XDG_CONFIG_HOME="%s" ./lua -E -i 2>&1',
+    input, xdg_dir)
+  local f = io.popen(cmd)
+  local output = f:read("*a")
+  f:close()
+  return output
+end
+
+
+-- ===== TEST 1: Main config file is loaded =====
+do
+  local tmpdir = tmpbase .. "_t1"
+  mkdir(tmpdir .. "/lush")
+  writefile(tmpdir .. "/lush/config", '_LUSH_TEST_MARKER = 42\n')
+
+  local out = run_with_config(tmpdir, "print(_LUSH_TEST_MARKER)")
+  assert(out:find("42"), "config file should set global: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+-- ===== TEST 2: config.d/ files are loaded in sorted order =====
+do
+  local tmpdir = tmpbase .. "_t2"
+  mkdir(tmpdir .. "/lush/config.d")
+  writefile(tmpdir .. "/lush/config.d/02-second.lua",
+    '_LUSH_ORDER = (_LUSH_ORDER or "") .. "B"\n')
+  writefile(tmpdir .. "/lush/config.d/01-first.lua",
+    '_LUSH_ORDER = (_LUSH_ORDER or "") .. "A"\n')
+  writefile(tmpdir .. "/lush/config.d/03-third.lua",
+    '_LUSH_ORDER = (_LUSH_ORDER or "") .. "C"\n')
+
+  local out = run_with_config(tmpdir, "print(_LUSH_ORDER)")
+  assert(out:find("ABC"), "config.d files should load in order: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+-- ===== TEST 3: Both config and config.d/ are loaded =====
+do
+  local tmpdir = tmpbase .. "_t3"
+  mkdir(tmpdir .. "/lush/config.d")
+  writefile(tmpdir .. "/lush/config", '_LUSH_SEQ = "M"\n')
+  writefile(tmpdir .. "/lush/config.d/01.lua",
+    '_LUSH_SEQ = _LUSH_SEQ .. "D"\n')
+
+  local out = run_with_config(tmpdir, "print(_LUSH_SEQ)")
+  assert(out:find("MD"), "main config runs before config.d: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+-- ===== TEST 4: -E suppresses config loading =====
+do
+  local tmpdir = tmpbase .. "_t4"
+  mkdir(tmpdir .. "/lush")
+  writefile(tmpdir .. "/lush/config", '_LUSH_SUPPRESSED = true\n')
+
+  local out = run_with_config_E(tmpdir, "print(_LUSH_SUPPRESSED)")
+  assert(out:find("nil"), "-E should suppress config: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+-- ===== TEST 5: Missing config dir doesn't error =====
+do
+  local tmpdir = tmpbase .. "_t5"
+  rmrf(tmpdir)  -- make sure it doesn't exist
+
+  -- should start normally without errors
+  local out = run_with_config(tmpdir, "print(42)")
+  assert(out:find("42"), "missing config dir should not error: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+-- ===== TEST 6: Only .lua files in config.d/ are loaded =====
+do
+  local tmpdir = tmpbase .. "_t6"
+  mkdir(tmpdir .. "/lush/config.d")
+  writefile(tmpdir .. "/lush/config.d/good.lua",
+    '_LUSH_LOADED = "yes"\n')
+  writefile(tmpdir .. "/lush/config.d/skip.txt",
+    '_LUSH_SKIPPED = "bad"\n')
+  writefile(tmpdir .. "/lush/config.d/README",
+    '_LUSH_README = "bad"\n')
+
+  local out = run_with_config(tmpdir, 'print(_LUSH_LOADED, _LUSH_SKIPPED)')
+  assert(out:find("yes"), "should load .lua files: " .. out)
+  assert(out:find("nil"), "should skip non-.lua files: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+-- ===== TEST 7: Config error is non-fatal =====
+do
+  local tmpdir = tmpbase .. "_t7"
+  mkdir(tmpdir .. "/lush")
+  writefile(tmpdir .. "/lush/config", 'error("config boom")\n')
+
+  local out = run_with_config(tmpdir, "print(99)")
+  assert(out:find("99"), "config error should be non-fatal: " .. out)
+
+  rmrf(tmpdir)
+end
+
+
+print "OK"