Replace $XDG_CONFIG_HOME with $JQ_CONFIG_HOME in search path

Introduce $JQ_CONFIG_HOME as a unified config home directory.

Author: nsfisis

docs/content/manual/dev/manual.yml

@@ -3708,12 +3708,11 @@ sections:
       For paths starting with `~/`, the user's home directory is
       substituted for `~`.
 
-      For paths starting with `$XDG_CONFIG_HOME/`, the value of the
-      environment variable `$XDG_CONFIG_HOME` is substituted for
-      `$XDG_CONFIG_HOME`. If the variable is not defined, `$HOME/.config`
-      is used as the default on non-Windows platforms. On Windows, these
-      paths are removed from the search path if the variable is not
-      defined.
+      For paths starting with `$JQ_CONFIG_HOME/`, `$JQ_CONFIG_HOME` is
+      resolved as follows: if the environment variable `$XDG_CONFIG_HOME`
+      is set and non-empty, `$XDG_CONFIG_HOME/jq` is used if the directory
+      exists; on non-Windows platforms, `~/.config/jq` is used if the
+      directory exists; otherwise, `~/.jq` is used as a fallback.
 
       For paths starting with `$ORIGIN/`, the directory where the jq
       executable is located is substituted for `$ORIGIN`.
@@ -3726,7 +3725,7 @@ sections:
       the default is appended.
 
       The default search path is the search path given to the `-L`
-      command-line option, else `["~/.jq", "$XDG_CONFIG_HOME/jq",
+      command-line option, else `["$JQ_CONFIG_HOME",
       "$ORIGIN/../lib/jq", "$ORIGIN/../lib"]`.
 
       Null and empty string path elements terminate search path

jq.1.prebuilt

@@ -48,7 +48,7 @@ static int path_is_relative(jv p) {
 // in the following order:
 // 1. lib_path
 // 2. -L paths passed in on the command line (from jq_state*) or builtin list
-static jv build_lib_search_chain(jq_state *jq, jv search_path, jv xdg_config_home, jv jq_origin, jv lib_origin) {
+static jv build_lib_search_chain(jq_state *jq, jv search_path, jv config_home, jv jq_origin, jv lib_origin) {
   assert(jv_get_kind(search_path) == JV_KIND_ARRAY);
   jv expanded = jv_array();
   jv expanded_elt;
@@ -66,14 +66,15 @@ static jv build_lib_search_chain(jq_state *jq, jv search_path, jv xdg_config_hom
     }
     if (strcmp(".",jv_string_value(path)) == 0) {
       expanded_elt = jv_copy(path);
-    } else if (strncmp("$XDG_CONFIG_HOME/",jv_string_value(path),sizeof("$XDG_CONFIG_HOME/") - 1) == 0) {
-      if (jv_is_valid(xdg_config_home)) {
+    } else if (strcmp("$JQ_CONFIG_HOME",jv_string_value(path)) == 0) {
+      expanded_elt = jv_copy(config_home);
+    } else if (strncmp("$JQ_CONFIG_HOME/",jv_string_value(path),sizeof("$JQ_CONFIG_HOME/") - 1) == 0) {
+      if (jv_is_valid(config_home)) {
         expanded_elt = jv_string_fmt("%s/%s",
-                                 jv_string_value(xdg_config_home),
-                                 jv_string_value(path) + sizeof ("$XDG_CONFIG_HOME/") - 1);
+                                 jv_string_value(config_home),
+                                 jv_string_value(path) + sizeof ("$JQ_CONFIG_HOME/") - 1);
       } else {
-        // Remove $XDG_CONFIG_HOME/* from the search path if $XDG_CONFIG_HOME is not defined.
-        expanded_elt = jv_null();
+        expanded_elt = jv_invalid();
       }
     } else if (strncmp("$ORIGIN/",jv_string_value(path),sizeof("$ORIGIN/") - 1) == 0) {
       expanded_elt = jv_string_fmt("%s/%s",
@@ -88,10 +89,14 @@ static jv build_lib_search_chain(jq_state *jq, jv search_path, jv xdg_config_hom
       expanded_elt = path;
       path = jv_invalid();
     }
-    expanded = jv_array_append(expanded, expanded_elt);
+    if (jv_is_valid(expanded_elt)) {
+      expanded = jv_array_append(expanded, expanded_elt);
+    } else {
+      jv_free(expanded_elt);
+    }
     jv_free(path);
   }
-  jv_free(xdg_config_home);
+  jv_free(config_home);
   jv_free(jq_origin);
   jv_free(lib_origin);
   jv_free(search_path);
@@ -143,26 +148,26 @@ static jv jv_basename(jv name) {
 }
 
 // Asummes validated relative path to module
-static jv find_lib(jq_state *jq, jv rel_path, jv search, const char *suffix, jv xdg_config_home, jv jq_origin, jv lib_origin) {
+static jv find_lib(jq_state *jq, jv rel_path, jv search, const char *suffix, jv config_home, jv jq_origin, jv lib_origin) {
   if (!jv_is_valid(rel_path)) {
     jv_free(search);
-    jv_free(xdg_config_home);
+    jv_free(config_home);
     jv_free(jq_origin);
     jv_free(lib_origin);
     return rel_path;
   }
   if (jv_get_kind(rel_path) != JV_KIND_STRING) {
     jv_free(rel_path);
     jv_free(search);
-    jv_free(xdg_config_home);
+    jv_free(config_home);
     jv_free(jq_origin);
     jv_free(lib_origin);
     return jv_invalid_with_msg(jv_string_fmt("Module path must be a string"));
   }
   if (jv_get_kind(search) != JV_KIND_ARRAY) {
     jv_free(rel_path);
     jv_free(search);
-    jv_free(xdg_config_home);
+    jv_free(config_home);
     jv_free(jq_origin);
     jv_free(lib_origin);
     return jv_invalid_with_msg(jv_string_fmt("Module search path must be an array"));
@@ -172,7 +177,7 @@ static jv find_lib(jq_state *jq, jv rel_path, jv search, const char *suffix, jv
   int ret;
 
   // Ideally we should cache this somewhere
-  search = build_lib_search_chain(jq, search, xdg_config_home, jq_origin, lib_origin);
+  search = build_lib_search_chain(jq, search, config_home, jq_origin, lib_origin);
   jv err = jv_array_get(jv_copy(search), 1);
   search = jv_array_get(search, 0);
 
@@ -254,7 +259,7 @@ static jv default_search(jq_state *jq, jv value) {
 }
 
 // XXX Split this into a util that takes a callback, and then...
-static int process_dependencies(jq_state *jq, jv xdg_config_home, jv jq_origin, jv lib_origin, block *src_block, struct lib_loading_state *lib_state) {
+static int process_dependencies(jq_state *jq, jv config_home, jv jq_origin, jv lib_origin, block *src_block, struct lib_loading_state *lib_state) {
   jv deps = block_take_imports(src_block);
   block bk = *src_block;
   int nerrors = 0;
@@ -283,7 +288,7 @@ static int process_dependencies(jq_state *jq, jv xdg_config_home, jv jq_origin,
     // dep is now freed; do not reuse
 
     // find_lib does a lot of work that could be cached...
-    jv resolved = find_lib(jq, relpath, search, is_data ? ".json" : ".jq", jv_copy(xdg_config_home), jv_copy(jq_origin), jv_copy(lib_origin));
+    jv resolved = find_lib(jq, relpath, search, is_data ? ".json" : ".jq", jv_copy(config_home), jv_copy(jq_origin), jv_copy(lib_origin));
     // XXX ...move the rest of this into a callback.
     if (!jv_is_valid(resolved)) {
       jv_free(as);
@@ -295,7 +300,7 @@ static int process_dependencies(jq_state *jq, jv xdg_config_home, jv jq_origin,
       jq_report_error(jq, jv_string_fmt("jq: error: %s\n",jv_string_value(emsg)));
       jv_free(emsg);
       jv_free(deps);
-      jv_free(xdg_config_home);
+      jv_free(config_home);
       jv_free(jq_origin);
       jv_free(lib_origin);
       return 1;
@@ -335,7 +340,7 @@ static int process_dependencies(jq_state *jq, jv xdg_config_home, jv jq_origin,
     jv_free(as);
   }
   jv_free(lib_origin);
-  jv_free(xdg_config_home);
+  jv_free(config_home);
   jv_free(jq_origin);
   jv_free(deps);
   return nerrors;
@@ -374,7 +379,7 @@ static int load_library(jq_state *jq, jv lib_path, int is_data, int raw, int opt
     locfile_free(src);
     if (nerrors == 0) {
       char *lib_origin = strdup(jv_string_value(lib_path));
-      nerrors += process_dependencies(jq, get_xdg_config_home(),
+      nerrors += process_dependencies(jq, get_config_home(),
                                       jq_get_jq_origin(jq),
                                       jv_string(dirname(lib_origin)),
                                       &program, lib_state);
@@ -398,7 +403,7 @@ static int load_library(jq_state *jq, jv lib_path, int is_data, int raw, int opt
 // as we do in process_dependencies.
 jv load_module_meta(jq_state *jq, jv mod_relpath) {
   // We can't know the caller's origin; we could though, if it was passed in
-  jv lib_path = find_lib(jq, validate_relpath(mod_relpath), jq_get_lib_dirs(jq), ".jq", get_xdg_config_home(), jq_get_jq_origin(jq), jv_null());
+  jv lib_path = find_lib(jq, validate_relpath(mod_relpath), jq_get_lib_dirs(jq), ".jq", get_config_home(), jq_get_jq_origin(jq), jv_null());
   if (!jv_is_valid(lib_path))
     return lib_path;
   jv meta = jv_null();
@@ -448,7 +453,7 @@ int load_program(jq_state *jq, struct locfile* src, block *out_block) {
     jv_free(home);
   }
 
-  nerrors = process_dependencies(jq, get_xdg_config_home(), jq_get_jq_origin(jq), jq_get_prog_origin(jq), &program, &lib_state);
+  nerrors = process_dependencies(jq, get_config_home(), jq_get_jq_origin(jq), jq_get_prog_origin(jq), &program, &lib_state);
   block libs = gen_noop();
   for (uint64_t i = 0; i < lib_state.ct; ++i) {
     free(lib_state.names[i]);

src/linker.c

@@ -570,8 +570,7 @@ int main(int argc, char* argv[]) {
 
   if (jv_get_kind(lib_search_paths) == JV_KIND_NULL) {
     // Default search path list
-    lib_search_paths = JV_ARRAY(jv_string("~/.jq"),
-                                jv_string("$XDG_CONFIG_HOME/jq"),
+    lib_search_paths = JV_ARRAY(jv_string("$JQ_CONFIG_HOME"),
                                 jv_string("$ORIGIN/../lib/jq"),
                                 jv_string("$ORIGIN/../lib"));
   }

src/main.c

@@ -126,25 +126,46 @@ jv get_home(void) {
   return ret;
 }
 
-// Get $XDG_CONFIG_HOME, fallbacking to $HOME/.config on non-Windows platforms.
-jv get_xdg_config_home(void) {
+static int is_directory(const char *path) {
+  struct stat sb;
+  return stat(path, &sb) == 0 && S_ISDIR(sb.st_mode);
+}
+
+// Get the config home base directory. Resolved as follows:
+//
+// 1. $XDG_CONFIG_HOME/jq if set, non-empty, and the directory exists
+// 2. Non-Windows only: $HOME/.config/jq if the directory exists
+// 3. $HOME/.jq
+jv get_config_home(void) {
   char *xdg_config_home = getenv("XDG_CONFIG_HOME");
   if (xdg_config_home && xdg_config_home[0]) {
-    return jv_string(xdg_config_home);
+    jv xdg_jq = jv_string_fmt("%s/jq", xdg_config_home);
+    if (is_directory(jv_string_value(xdg_jq))) {
+      return xdg_jq;
+    }
+    jv_free(xdg_jq);
   }
 
-#ifndef WIN32
-  // Fallback to $HOME/.config on non-Windows platforms.
   jv home = get_home();
-  if (jv_is_valid(home)) {
-    jv ret = jv_string_fmt("%s/.config", jv_string_value(home));
+  if (!jv_is_valid(home)) {
     jv_free(home);
-    return ret;
+    return jv_invalid_with_msg(jv_string("No config home directory available"));
   }
-  jv_free(home);
+
+#ifndef WIN32
+  // Fallback to $HOME/.config/jq on non-Windows platforms.
+  jv config_jq = jv_string_fmt("%s/.config/jq", jv_string_value(home));
+  if (is_directory(jv_string_value(config_jq))) {
+    jv_free(home);
+    return config_jq;
+  }
+  jv_free(config_jq);
 #endif
+  // Fallback to $HOME/.jq.
+  jv dot_jq = jv_string_fmt("%s/.jq", jv_string_value(home));
+  jv_free(home);
 
-  return jv_invalid_with_msg(jv_string("No $XDG_CONFIG_HOME available"));
+  return dot_jq;
 }
 
 jv jq_realpath(jv path) {

src/util.c

@@ -15,7 +15,7 @@
 
 jv expand_path(jv);
 jv get_home(void);
-jv get_xdg_config_home(void);
+jv get_config_home(void);
 jv jq_realpath(jv);
 
 /*

src/util.h

@@ -382,9 +382,9 @@ if [ "$(HOME=/nonexistent XDG_CONFIG_HOME="$mods/xdg1" $VALGRIND $Q $JQ -nr 'inc
     echo "Failed to load module from \$XDG_CONFIG_HOME/jq/" 1>&2
     exit 1
 fi
-## ~/.jq/ should be searched before $XDG_CONFIG_HOME/jq/
-if [ "$(HOME="$mods/home3" XDG_CONFIG_HOME="$mods/xdg2" $VALGRIND $Q $JQ -nr 'include "priority_test"; test')" != "qux" ]; then
-    echo "~/.jq/ should take priority over \$XDG_CONFIG_HOME/jq/" 1>&2
+## $JQ_CONFIG_HOME/jq/ should be searched before ~/.jq/
+if [ "$(HOME="$mods/home3" XDG_CONFIG_HOME="$mods/xdg2" $VALGRIND $Q $JQ -nr 'include "priority_test"; test')" != "baz" ]; then
+    echo "\$JQ_CONFIG_HOME/jq/ should take priority over ~/.jq/" 1>&2
     exit 1
 fi
 if $msys || $mingw; then
@@ -399,16 +399,21 @@ if $msys || $mingw; then
         exit 1
     fi
 else
-    ## If $XDG_CONFIG_HOME is unset, fallback to $HOME/.config/jq/
+    ## If $XDG_CONFIG_HOME is unset and $HOME/.config/jq exists, fallback to $HOME/.config/jq/
     if [ "$(unset XDG_CONFIG_HOME; HOME="$mods/home3" $VALGRIND $Q $JQ -nr 'include "cfg"; test')" != "bar" ]; then
         echo "Failed to fallback to \$HOME/.config/jq/ when \$XDG_CONFIG_HOME is unset" 1>&2
         exit 1
     fi
-    ## If $XDG_CONFIG_HOME is an empty string, fallback to $HOME/.config/jq/
+    ## If $XDG_CONFIG_HOME is an empty string and $HOME/.config/jq exists, fallback to $HOME/.config/jq/
     if [ "$(XDG_CONFIG_HOME="" HOME="$mods/home3" $VALGRIND $Q $JQ -nr 'include "cfg"; test')" != "bar" ]; then
         echo "Failed to fallback to \$HOME/.config/jq/ when \$XDG_CONFIG_HOME is empty" 1>&2
         exit 1
     fi
+    ## If $HOME/.config/jq does not exist, do not fallback to $HOME/.config/
+    if unset XDG_CONFIG_HOME; HOME="$mods/home1" $VALGRIND $Q $JQ -nr 'include "cfg"; test' 2>/dev/null; then
+        echo "Should not fallback to \$HOME/.config/ when \$HOME/.config/jq does not exist" 1>&2
+        exit 1
+    fi
 fi
 
 cd "$JQBASEDIR" # so that relative library paths are guaranteed correct