Fix compatibility of cached expanded load path

* file.c (rb_get_path_check_to_string): extract from
  rb_get_path_check(). We change the spec not to call to_path of
  String object.

* file.c (rb_get_path_check_convert): extract from rb_get_path_check().

* file.c (rb_get_path_check): follow the above change.

* file.c (rb_file_expand_path_fast): remove check_expand_path_args().
  Instead we call it in load.c.

* file.c (rb_find_file_ext_safe): use rb_get_expanded_load_path() to
  reduce expand cost.

* file.c (rb_find_file_safe): ditto.

* internal.h (rb_get_expanded_load_path): add a declaration.

* internal.h (rb_get_path_check_to_string, rb_get_path_check_convert):
  add declarations.

* load.c (rb_construct_expanded_load_path): fix for compatibility.
  Same checks in rb_get_path_check() are added. We don't replace
  $LOAD_PATH and ensure that String object of $LOAD_PATH are frozen.
  We don't freeze non String object and expand it every times. We add
  arguments for expanding load path partially and checking if load path
  have relative paths or non String objects.

* load.c (load_path_getcwd): get current working directory for checking
  if it's changed when getting load path.

* load.c (rb_get_expanded_load_path): fix for rebuilding cache properly.
  We check if current working directory is changed and rebuild expanded
  load path cache. We expand paths which start with ~ (User HOME) and
  non String objects every times for compatibility. We make this
  accessible from other source files.

* load.c (rb_feature_provided): call rb_get_path() since we changed
  rb_file_expand_path_fast() not to call it.

* load.c (Init_load): initialize vm->load_path_check_cache.

* vm.c (rb_vm_mark): mark vm->load_path_check_cache for GC.

* vm_core.h (rb_vm_struct): add vm->load_path_check_cache to store data
  to check load path cache validity.

* test/ruby/test_require.rb (TestRequire): add tests for require
  compatibility related to cached expanded load path.
  [ruby-core:47970] [Bug #7158]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37482 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

7 files changed, 276 insertions, 13 deletions

diff --git a/ChangeLog b/ChangeLog
index 3d35baad88..ea3d75a645 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,56 @@
+Mon Nov  5 23:28:57 2012  Hiroshi Shirosaki  <h.shirosaki@gmail.com>
+
+	* file.c (rb_get_path_check_to_string): extract from
+	  rb_get_path_check(). We change the spec not to call to_path of
+	  String object.
+
+	* file.c (rb_get_path_check_convert): extract from rb_get_path_check().
+
+	* file.c (rb_get_path_check): follow the above change.
+
+	* file.c (rb_file_expand_path_fast): remove check_expand_path_args().
+	  Instead we call it in load.c.
+
+	* file.c (rb_find_file_ext_safe): use rb_get_expanded_load_path() to
+	  reduce expand cost.
+
+	* file.c (rb_find_file_safe): ditto.
+
+	* internal.h (rb_get_expanded_load_path): add a declaration.
+
+	* internal.h (rb_get_path_check_to_string, rb_get_path_check_convert):
+	  add declarations.
+
+	* load.c (rb_construct_expanded_load_path): fix for compatibility.
+	  Same checks in rb_get_path_check() are added. We don't replace
+	  $LOAD_PATH and ensure that String object of $LOAD_PATH are frozen.
+	  We don't freeze non String object and expand it every times. We add
+	  arguments for expanding load path partially and checking if load path
+	  have relative paths or non String objects.
+
+	* load.c (load_path_getcwd): get current working directory for checking
+	  if it's changed when getting load path.
+
+	* load.c (rb_get_expanded_load_path): fix for rebuilding cache properly.
+	  We check if current working directory is changed and rebuild expanded
+	  load path cache. We expand paths which start with ~ (User HOME) and
+	  non String objects every times for compatibility. We make this
+	  accessible from other source files.
+
+	* load.c (rb_feature_provided): call rb_get_path() since we changed
+	  rb_file_expand_path_fast() not to call it.
+
+	* load.c (Init_load): initialize vm->load_path_check_cache.
+
+	* vm.c (rb_vm_mark): mark vm->load_path_check_cache for GC.
+
+	* vm_core.h (rb_vm_struct): add vm->load_path_check_cache to store data
+	  to check load path cache validity.
+
+	* test/ruby/test_require.rb (TestRequire): add tests for require
+	  compatibility related to cached expanded load path.
+	  [ruby-core:47970] [Bug #7158]
+
 Mon Nov  5 23:26:05 2012  Greg Price  <price@mit.edu>
 
 	* load.c (rb_get_expanded_load_path): cache the expanded load
diff --git a/file.c b/file.c
index 5951d7b5b5..12622a380f 100644
--- a/file.c
+++ b/file.c
@@ -167,8 +167,8 @@ check_path_encoding(VALUE str)
     return enc;
 }
 
-static VALUE
-rb_get_path_check(VALUE obj, int level)
+VALUE
+rb_get_path_check_to_string(VALUE obj, int level)
 {
     VALUE tmp;
     ID to_path;
@@ -177,13 +177,21 @@ rb_get_path_check(VALUE obj, int level)
 	rb_insecure_operation();
     }
 
+    if (RB_TYPE_P(obj, T_STRING)) {
+	return obj;
+    }
     CONST_ID(to_path, "to_path");
     tmp = rb_check_funcall(obj, to_path, 0, 0);
     if (tmp == Qundef) {
 	tmp = obj;
     }
     StringValue(tmp);
+    return tmp;
+}
 
+VALUE
+rb_get_path_check_convert(VALUE obj, VALUE tmp, int level)
+{
     tmp = file_path_convert(tmp);
     if (obj != tmp && insecure_obj_p(tmp, level)) {
 	rb_insecure_operation();
@@ -195,6 +203,13 @@ rb_get_path_check(VALUE obj, int level)
     return rb_str_new4(tmp);
 }
 
+static VALUE
+rb_get_path_check(VALUE obj, int level)
+{
+    VALUE tmp = rb_get_path_check_to_string(obj, level);
+    return rb_get_path_check_convert(obj, tmp, level);
+}
+
 VALUE
 rb_get_path_no_checksafe(VALUE obj)
 {
@@ -3255,7 +3270,6 @@ rb_file_expand_path(VALUE fname, VALUE dname)
 VALUE
 rb_file_expand_path_fast(VALUE fname, VALUE dname)
 {
-    check_expand_path_args(fname, dname);
     return rb_file_expand_path_internal(fname, dname, 0, 0, EXPAND_PATH_BUFFER());
 }
 
@@ -5258,7 +5272,7 @@ rb_find_file_ext_safe(VALUE *filep, const char *const *ext, int safe_level)
 	rb_raise(rb_eSecurityError, "loading from non-absolute path %s", f);
     }
 
-    RB_GC_GUARD(load_path) = rb_get_load_path();
+    RB_GC_GUARD(load_path) = rb_get_expanded_load_path();
     if (!load_path) return 0;
 
     fname = rb_str_dup(*filep);
@@ -5323,7 +5337,7 @@ rb_find_file_safe(VALUE path, int safe_level)
 	rb_raise(rb_eSecurityError, "loading from non-absolute path %s", f);
     }
 
-    RB_GC_GUARD(load_path) = rb_get_load_path();
+    RB_GC_GUARD(load_path) = rb_get_expanded_load_path();
     if (load_path) {
 	long i;
 
diff --git a/internal.h b/internal.h
index e538de4404..6e6a071f92 100644
--- a/internal.h
+++ b/internal.h
@@ -108,6 +108,8 @@ void rb_file_const(const char*, VALUE);
 int rb_file_load_ok(const char *);
 VALUE rb_file_expand_path_fast(VALUE, VALUE);
 VALUE rb_file_expand_path_internal(VALUE, VALUE, int, int, VALUE);
+VALUE rb_get_path_check_to_string(VALUE, int);
+VALUE rb_get_path_check_convert(VALUE, VALUE, int);
 void Init_File(void);
 
 #ifdef _WIN32
@@ -133,6 +135,7 @@ VALUE rb_iseq_clone(VALUE iseqval, VALUE newcbase);
 
 /* load.c */
 VALUE rb_get_load_path(void);
+VALUE rb_get_expanded_load_path(void);
 NORETURN(void rb_load_fail(VALUE, const char*));
 
 /* math.c */
diff --git a/load.c b/load.c
index 83bc73f675..650b931661 100644
--- a/load.c
+++ b/load.c
@@ -33,22 +33,58 @@ rb_get_load_path(void)
     return load_path;
 }
 
+enum expand_type {
+    EXPAND_ALL,
+    EXPAND_RELATIVE,
+    EXPAND_HOME,
+    EXPAND_NON_CACHE
+};
+
+/* Construct expanded load path and store it to cache.
+   We rebuild load path partially if the cache is invalid.
+   We don't cache non string object and expand it every times. We ensure that
+   string objects in $LOAD_PATH are frozen.
+ */
 static void
-rb_construct_expanded_load_path(void)
+rb_construct_expanded_load_path(int type, int *has_relative, int *has_non_cache)
 {
     rb_vm_t *vm = GET_VM();
     VALUE load_path = vm->load_path;
+    VALUE expanded_load_path = vm->expanded_load_path;
     VALUE ary;
     long i;
+    int level = rb_safe_level();
 
     ary = rb_ary_new2(RARRAY_LEN(load_path));
     for (i = 0; i < RARRAY_LEN(load_path); ++i) {
 	VALUE path, as_str, expanded_path;
+	int is_string, non_cache;
+	char *as_cstr;
 	as_str = path = RARRAY_PTR(load_path)[i];
-	StringValue(as_str);
-	if (as_str != path)
-	    rb_ary_store(load_path, i, as_str);
-	rb_str_freeze(as_str);
+	is_string = RB_TYPE_P(path, T_STRING) ? 1 : 0;
+	non_cache = !is_string ? 1 : 0;
+	as_str = rb_get_path_check_to_string(path, level);
+	as_cstr = RSTRING_PTR(as_str);
+
+	if (!non_cache) {
+	    if ((type == EXPAND_RELATIVE &&
+		    rb_is_absolute_path(as_cstr)) ||
+		(type == EXPAND_HOME &&
+		    (!as_cstr[0] || as_cstr[0] != '~')) ||
+		(type == EXPAND_NON_CACHE)) {
+		    /* Use cached expanded path. */
+		    rb_ary_push(ary, RARRAY_PTR(expanded_load_path)[i]);
+		    continue;
+	    }
+	}
+	if (!*has_relative && !rb_is_absolute_path(as_cstr))
+	    *has_relative = 1;
+	if (!*has_non_cache && non_cache)
+	    *has_non_cache = 1;
+	/* Freeze only string object. We expand other objects every times. */
+	if (is_string)
+	    rb_str_freeze(path);
+	as_str = rb_get_path_check_convert(path, as_str, level);
 	expanded_path = rb_file_expand_path_fast(as_str, Qnil);
 	rb_str_freeze(expanded_path);
 	rb_ary_push(ary, expanded_path);
@@ -59,12 +95,56 @@ rb_construct_expanded_load_path(void)
 }
 
 static VALUE
+load_path_getcwd(void)
+{
+    char *cwd = my_getcwd();
+    VALUE cwd_str = rb_filesystem_str_new_cstr(cwd);
+    xfree(cwd);
+    return cwd_str;
+}
+
+VALUE
 rb_get_expanded_load_path(void)
 {
     rb_vm_t *vm = GET_VM();
+    const VALUE non_cache = Qtrue;
+
     if (!rb_ary_shared_with_p(vm->load_path_snapshot, vm->load_path)) {
-	/* The load path was modified.	Rebuild the expanded load path. */
-	rb_construct_expanded_load_path();
+	/* The load path was modified. Rebuild the expanded load path. */
+	int has_relative = 0, has_non_cache = 0;
+	rb_construct_expanded_load_path(EXPAND_ALL, &has_relative, &has_non_cache);
+	if (has_relative) {
+	    vm->load_path_check_cache = load_path_getcwd();
+	}
+	else if (has_non_cache) {
+	    /* Non string object. */
+	    vm->load_path_check_cache = non_cache;
+	}
+	else {
+	    vm->load_path_check_cache = 0;
+	}
+    }
+    else if (vm->load_path_check_cache == non_cache) {
+	int has_relative = 1, has_non_cache = 1;
+	/* Expand only non-cacheable objects. */
+	rb_construct_expanded_load_path(EXPAND_NON_CACHE,
+					&has_relative, &has_non_cache);
+    }
+    else if (vm->load_path_check_cache) {
+	int has_relative = 1, has_non_cache = 1;
+	VALUE cwd = load_path_getcwd();
+	if (!rb_str_equal(vm->load_path_check_cache, cwd)) {
+	    /* Current working directory or filesystem encoding was changed.
+	       Expand relative load path and non-cacheable objects again. */
+	    vm->load_path_check_cache = cwd;
+	    rb_construct_expanded_load_path(EXPAND_RELATIVE,
+					    &has_relative, &has_non_cache);
+	}
+	else {
+	    /* Expand only tilde (User HOME) and non-cacheable objects. */
+	    rb_construct_expanded_load_path(EXPAND_HOME,
+					    &has_relative, &has_non_cache);
+	}
     }
     return vm->expanded_load_path;
 }
@@ -392,7 +472,7 @@ rb_feature_provided(const char *feature, const char **loading)
 
     if (*feature == '.' &&
 	(feature[1] == '/' || strncmp(feature+1, "./", 2) == 0)) {
-	fullpath = rb_file_expand_path_fast(rb_str_new2(feature), Qnil);
+	fullpath = rb_file_expand_path_fast(rb_get_path(rb_str_new2(feature)), Qnil);
 	feature = RSTRING_PTR(fullpath);
     }
     if (ext && !strchr(ext, '/')) {
@@ -963,6 +1043,7 @@ Init_load()
     vm->load_path = rb_ary_new();
     vm->expanded_load_path = rb_ary_new();
     vm->load_path_snapshot = rb_ary_new();
+    vm->load_path_check_cache = 0;
 
     rb_define_virtual_variable("$\"", get_loaded_features, 0);
     rb_define_virtual_variable("$LOADED_FEATURES", get_loaded_features, 0);
diff --git a/test/ruby/test_require.rb b/test/ruby/test_require.rb
index a7c75d06bf..dbbe483578 100644
--- a/test/ruby/test_require.rb
+++ b/test/ruby/test_require.rb
@@ -435,4 +435,114 @@ class TestRequire < Test::Unit::TestCase
     $:.replace(loadpath)
     $".replace(features)
   end
+
+  def test_require_changed_current_dir
+    bug7158 = '[ruby-core:47970]'
+    Dir.mktmpdir {|tmp|
+      Dir.chdir(tmp) {
+        Dir.mkdir("a")
+        Dir.mkdir("b")
+        open(File.join("a", "foo.rb"), "w") {}
+        open(File.join("b", "bar.rb"), "w") {|f|
+          f.puts "p :ok"
+        }
+        assert_in_out_err([], <<-INPUT, %w(:ok), [], bug7158)
+          $: << "."
+          Dir.chdir("a")
+          require "foo"
+          Dir.chdir("../b")
+          p :ng unless require "bar"
+          Dir.chdir("..")
+          p :ng if require "b/bar"
+        INPUT
+      }
+    }
+  end
+
+  def test_require_not_modified_load_path
+    bug7158 = '[ruby-core:47970]'
+    Dir.mktmpdir {|tmp|
+      Dir.chdir(tmp) {
+        open("foo.rb", "w") {}
+        assert_in_out_err([], <<-INPUT, %w(:ok), [], bug7158)
+          a = Object.new
+          def a.to_str
+            "#{tmp}"
+          end
+          $: << a
+          require "foo"
+          last_path = $:.pop
+          p :ok if last_path == a && last_path.class == Object
+        INPUT
+      }
+    }
+  end
+
+  def test_require_changed_home
+    bug7158 = '[ruby-core:47970]'
+    Dir.mktmpdir {|tmp|
+      Dir.chdir(tmp) {
+        open("foo.rb", "w") {}
+        Dir.mkdir("a")
+        open(File.join("a", "bar.rb"), "w") {}
+        assert_in_out_err([], <<-INPUT, %w(:ok), [], bug7158)
+          $: << '~'
+          ENV['HOME'] = "#{tmp}"
+          require "foo"
+          ENV['HOME'] = "#{tmp}/a"
+          p :ok if require "bar"
+        INPUT
+      }
+    }
+  end
+
+  def test_require_to_path_redefined_in_load_path
+    bug7158 = '[ruby-core:47970]'
+    Dir.mktmpdir {|tmp|
+      Dir.chdir(tmp) {
+        open("foo.rb", "w") {}
+        assert_in_out_err([], <<-INPUT, %w(:ok), [], bug7158)
+          a = Object.new
+          def a.to_path
+            "bar"
+          end
+          $: << a
+          begin
+            require "foo"
+            p :ng
+          rescue LoadError
+          end
+          def a.to_path
+            "#{tmp}"
+          end
+          p :ok if require "foo"
+        INPUT
+      }
+    }
+  end
+
+  def test_require_to_str_redefined_in_load_path
+    bug7158 = '[ruby-core:47970]'
+    Dir.mktmpdir {|tmp|
+      Dir.chdir(tmp) {
+        open("foo.rb", "w") {}
+        assert_in_out_err([], <<-INPUT, %w(:ok), [], bug7158)
+          a = Object.new
+          def a.to_str
+            "foo"
+          end
+          $: << a
+          begin
+            require "foo"
+            p :ng
+          rescue LoadError
+          end
+          def a.to_str
+            "#{tmp}"
+          end
+          p :ok if require "foo"
+        INPUT
+      }
+    }
+  end
 end
diff --git a/vm.c b/vm.c
index 61640b891d..23f6996895 100644
--- a/vm.c
+++ b/vm.c
@@ -1513,6 +1513,7 @@ rb_vm_mark(void *ptr)
 	RUBY_MARK_UNLESS_NULL(vm->mark_object_ary);
 	RUBY_MARK_UNLESS_NULL(vm->load_path);
 	RUBY_MARK_UNLESS_NULL(vm->load_path_snapshot);
+	RUBY_MARK_UNLESS_NULL(vm->load_path_check_cache);
 	RUBY_MARK_UNLESS_NULL(vm->expanded_load_path);
 	RUBY_MARK_UNLESS_NULL(vm->loaded_features);
 	RUBY_MARK_UNLESS_NULL(vm->loaded_features_snapshot);
diff --git a/vm_core.h b/vm_core.h
index 81588ca387..a50ff5287f 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -355,6 +355,7 @@ typedef struct rb_vm_struct {
     VALUE top_self;
     VALUE load_path;
     VALUE load_path_snapshot;
+    VALUE load_path_check_cache;
     VALUE expanded_load_path;
     VALUE loaded_features;
     VALUE loaded_features_snapshot;