Subject: Re: bug#37445: 27.0.50; Permission denied after make install

From: Paul Eggert <[email-masked]>
Date: Wed, 18 Sep 2019 23:57:23 -0700

I installed the attached patch, which should fix the bug even when PICKY_EACCES 
is nonzero. Boldly closing the bug report.
>From dff4f9c759f5cf19047719716ea5ee8ffdc3006e Mon Sep 17 00:00:00 2001
From: Paul Eggert <[email-masked]>
Date: Wed, 18 Sep 2019 23:53:46 -0700
Subject: [PATCH] Omit some overenthusiastic file-truename calls

Problem reported by Tino Calancha (Bug#37445).
* src/emacs.c (init_cmdargs): Call file-truename only if
needed, i.e., if invocation-directory ends in "/i386/" on
WINDOWSNT.
* src/lread.c (readevalloop): If the sourcename is not
absolute, make it absolute.  There is no need to convert
non-absolute files into truenames, since absolute files are
not converted into truenames.
(init_lread): Do not convert source-directory into a truename
at startup.  There is no need to do so in a dumped Emacs since
an absolute file name suffices.  The source directory might
not even exist any more, or might have been replaced by an
interloper who takes advantage of the truename calculation.
(syms_of_lread): Remove Qfile_truename; no longer needed.
---
 src/emacs.c | 14 +++++++++-----
 src/lread.c | 11 +++--------
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/src/emacs.c b/src/emacs.c
index eb732810db..8a8d8b558e 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -479,9 +479,6 @@ init_cmdargs (int argc, char **argv, int skip_args, char const *original_pwd)
 
   if (!NILP (Vinvocation_directory))
     {
-      if (NILP (Vpurify_flag) && !NILP (Ffboundp (Qfile_truename)))
-        Vinvocation_directory = call1 (Qfile_truename, Vinvocation_directory);
-
       dir = Vinvocation_directory;
 #ifdef WINDOWSNT
       /* If we are running from the build directory, set DIR to the
@@ -490,8 +487,15 @@ init_cmdargs (int argc, char **argv, int skip_args, char const *original_pwd)
       if (SBYTES (dir) > sizeof ("/i386/") - 1
 	  && 0 == strcmp (SSDATA (dir) + SBYTES (dir) - sizeof ("/i386/") + 1,
 			  "/i386/"))
-	dir = Fexpand_file_name (build_string ("../.."), dir);
-#else  /* !WINDOWSNT */
+	{
+	  if (NILP (Vpurify_flag))
+	    {
+	      Lisp_Object file_truename = intern ("file-truename");
+	      if (!NILP (Ffboundp (file_truename)))
+		dir = call1 (file_truename, dir);
+	    }
+	  dir = Fexpand_file_name (build_string ("../.."), dir);
+	}
 #endif
       name = Fexpand_file_name (Vinvocation_name, dir);
       while (1)
diff --git a/src/lread.c b/src/lread.c
index 99e0ce30ba..4f3446b09d 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -1999,11 +1999,10 @@ readevalloop (Lisp_Object readcharfun,
 	    (NILP (lex_bound) || EQ (lex_bound, Qunbound)
 	     ? Qnil : list1 (Qt)));
 
-  /* Try to ensure sourcename is a truename, except whilst preloading.  */
+  /* Ensure sourcename is absolute, except whilst preloading.  */
   if (!will_dump_p ()
-      && !NILP (sourcename) && !NILP (Ffile_name_absolute_p (sourcename))
-      && !NILP (Ffboundp (Qfile_truename)))
-    sourcename = call1 (Qfile_truename, sourcename) ;
+      && !NILP (sourcename) && !NILP (Ffile_name_absolute_p (sourcename)))
+    sourcename = Fexpand_file_name (sourcename, Qnil);
 
   LOADHIST_ATTACH (sourcename);
 
@@ -4678,9 +4677,6 @@ load_path_default (void)
 void
 init_lread (void)
 {
-  if (NILP (Vpurify_flag) && !NILP (Ffboundp (Qfile_truename)))
-    Vsource_directory = call1 (Qfile_truename, Vsource_directory);
-
   /* First, set Vload_path.  */
 
   /* Ignore EMACSLOADPATH when dumping.  */
@@ -5100,7 +5096,6 @@ this variable will become obsolete.  */);
   DEFSYM (Qload, "load");
   DEFSYM (Qload_file_name, "load-file-name");
   DEFSYM (Qeval_buffer_list, "eval-buffer-list");
-  DEFSYM (Qfile_truename, "file-truename");
   DEFSYM (Qdir_ok, "dir-ok");
   DEFSYM (Qdo_after_load_evaluation, "do-after-load-evaluation");
 
-- 
2.17.1