bug#24441: 24.5; rename directory in dired to change case

[Paul Eggert <eggert@cs.ucla.edu>]

[-- Attachment #1: Type: text/plain, Size: 636 bytes --]

As mentioned in the thread containing this message:

http://lists.gnu.org/archive/html/emacs-devel/2017-05/msg00521.html

the DARWIN_OS_CASE_SENSITIVE_FIXME code was getting in the way of maintenance, 
and doesn't seem to be working or needed or used. I attempted to get it to work 
in the first attached patch (untested), and then removed it as described in the 
second attached patch. If that code ever turns out to be useful someone can 
revert the second patch and give my attempt a whirl.

As I understand it, the original bug was fixed last year; this email is merely 
about trying to make the fix easier to maintain.

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Narrow-DARWIN_OS_CASE_SENSITIVE_FIXME-to-1-choice.patch --]
[-- Type: text/x-patch; name="0001-Narrow-DARWIN_OS_CASE_SENSITIVE_FIXME-to-1-choice.patch", Size: 5240 bytes --]

From 075bd64609446e741a6efbcd6cd6e232db8d1df6 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 20 May 2017 22:51:32 -0700
Subject: [PATCH 1/2] Narrow DARWIN_OS_CASE_SENSITIVE_FIXME to 1 choice

* etc/PROBLEMS: Document this (Bug#24441).
* src/fileio.c (file_name_case_insensitive_p): Prefer pathconf
with _PC_CASE_SENSITIVE, if it works, to
DARWIN_OS_CASE_SENSITIVE_FIXME code.
Support just one method for DARWIN_OS_CASE_SENSITIVE_FIXME,
which matches the Apple documentation more precisely.
---
 etc/PROBLEMS |  5 ++---
 src/fileio.c | 68 ++++++++++++++++++++----------------------------------------
 2 files changed, 24 insertions(+), 49 deletions(-)

diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index e415887..ff88aa3 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -2486,9 +2486,8 @@ If you do, please send it to bug-gnu-emacs@gnu.org so we can list it here.
 The implementation of that function on Mac OS X uses pathconf with the
 _PC_CASE_SENSITIVE flag.  There have been reports that this use of
 pathconf does not work reliably.  If you have a problem, please
-recompile Emacs with -D DARWIN_OS_CASE_SENSITIVE_FIXME=1 or
--D DARWIN_OS_CASE_SENSITIVE_FIXME=2, and file a bug report saying
-whether this fixed your problem.
+recompile Emacs with -D DARWIN_OS_CASE_SENSITIVE_FIXME, and file a bug
+report saying whether this fixed your problem.
 
 * Build-time problems
 
diff --git a/src/fileio.c b/src/fileio.c
index e5e3505..17659b6 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2256,65 +2256,41 @@ static bool
 file_name_case_insensitive_p (const char *filename)
 {
   /* Use pathconf with _PC_CASE_INSENSITIVE or _PC_CASE_SENSITIVE if
-     those flags are available.  As of this writing (2016-11-14),
+     those flags are available.  As of this writing (2017-05-20),
      Cygwin is the only platform known to support the former (starting
-     with Cygwin-2.6.1), and Mac OS X is the only platform known to
-     support the latter.
-
-     There have been reports that pathconf with _PC_CASE_SENSITIVE
-     does not work reliably on Mac OS X.  If you have a problem,
-     please recompile Emacs with -D DARWIN_OS_CASE_SENSITIVE_FIXME=1 or
-     -D DARWIN_OS_CASE_SENSITIVE_FIXME=2, and file a bug report saying
-     whether this fixed your problem.  */
+     with Cygwin-2.6.1), and macOS is the only platform known to
+     support the latter.  */
 
 #ifdef _PC_CASE_INSENSITIVE
   int res = pathconf (filename, _PC_CASE_INSENSITIVE);
   if (res >= 0)
     return res > 0;
-#elif defined _PC_CASE_SENSITIVE && !defined DARWIN_OS_CASE_SENSITIVE_FIXME
+#elif defined _PC_CASE_SENSITIVE
   int res = pathconf (filename, _PC_CASE_SENSITIVE);
   if (res >= 0)
     return res == 0;
 #endif
 
-#ifdef DARWIN_OS
-# ifndef DARWIN_OS_CASE_SENSITIVE_FIXME
-  int DARWIN_OS_CASE_SENSITIVE_FIXME = 0;
-# endif
+  /* There have been reports that pathconf with _PC_CASE_SENSITIVE
+     does not work reliably on Mac OS X.  If you have a problem,
+     please recompile Emacs with -D DARWIN_OS_CASE_SENSITIVE_FIXME=1 or
+     -D DARWIN_OS_CASE_SENSITIVE_FIXME=2, and file a bug report saying
+     whether this fixed your problem.  */
 
-  if (DARWIN_OS_CASE_SENSITIVE_FIXME == 1)
-    {
-      /* This is based on developer.apple.com's getattrlist man page.  */
-      struct attrlist alist = {.volattr = ATTR_VOL_CAPABILITIES};
-      vol_capabilities_attr_t vcaps;
-      if (getattrlist (filename, &alist, &vcaps, sizeof vcaps, 0) == 0)
-	{
-	  if (vcaps.valid[VOL_CAPABILITIES_FORMAT] & VOL_CAP_FMT_CASE_SENSITIVE)
-	    return ! (vcaps.capabilities[VOL_CAPABILITIES_FORMAT]
-		      & VOL_CAP_FMT_CASE_SENSITIVE);
-	}
-    }
-# if DARWIN_OS_CASE_SENSITIVE_FIXME == 2
-    {
-      /* The following is based on
-	 http://lists.apple.com/archives/darwin-dev/2007/Apr/msg00010.html.
-	 It is normally not even compiled, since it runs afoul of
-	 static checking.  See:
-	 http://lists.gnu.org/archive/html/emacs-devel/2017-05/msg00495.html
-         */
-      struct attrlist alist;
-      unsigned char buffer[sizeof (vol_capabilities_attr_t) + sizeof (size_t)];
-
-      memset (&alist, 0, sizeof (alist));
-      alist.volattr = ATTR_VOL_CAPABILITIES;
-      if (getattrlist (filename, &alist, buffer, sizeof (buffer), 0)
-	  || !(alist.volattr & ATTR_VOL_CAPABILITIES))
-	return 0;
-      vol_capabilities_attr_t *vcaps = buffer;
-      return !(vcaps->capabilities[0] & VOL_CAP_FMT_CASE_SENSITIVE);
-    }
+#ifdef DARWIN_OS_CASE_SENSITIVE_FIXME
+# ifdef VOL_CAP_FMT_CASE_SENSITIVE
+  {
+    struct attrlist alist = {.bitmapcount = ATTR_BIT_MAP_COUNT,
+			     .volattr = ATTR_VOL_INFO | ATTR_VOL_CAPABILITIES};
+    struct { uint32_t len; vol_capabilities_attr_t caps; } vcaps
+      __attribute__ ((aligned (4), packed));
+    int i = VOL_CAPABILITIES_FORMAT;
+    if (getattrlist (filename, &alist, &vcaps, sizeof vcaps, 0) == 0
+	&& (vcaps.caps.valid[i] & VOL_CAP_FMT_CASE_SENSITIVE))
+      return ! (vcaps.caps.capabilities[i] & VOL_CAP_FMT_CASE_SENSITIVE);
+  }
 # endif
-#endif	/* DARWIN_OS */
+#endif
 
 #if defined CYGWIN || defined DOS_NT
   return true;
-- 
2.7.4


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #3: 0002-Remove-DARWIN_OS_CASE_SENSITIVE_FIXME-code.patch --]
[-- Type: text/x-patch; name="0002-Remove-DARWIN_OS_CASE_SENSITIVE_FIXME-code.patch", Size: 2542 bytes --]

From b35293dfd0e9dd95a88ac01051655d0d2d105992 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 20 May 2017 22:55:17 -0700
Subject: [PATCH 2/2] Remove DARWIN_OS_CASE_SENSITIVE_FIXME code

It does not appear to be needed (Bug#24441).
* etc/PROBLEMS: Remove DARWIN_OS_CASE_SENSITIVE_FIXME stuff.
* src/fileio.c (file_name_case_insensitive_p):
Remove DARWIN_OS_CASE_SENSITIVE_FIXME code.
---
 etc/PROBLEMS | 10 ----------
 src/fileio.c | 21 ---------------------
 2 files changed, 31 deletions(-)

diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index ff88aa3..593eb6b 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -2479,16 +2479,6 @@ please call support for your X-server and see if you can get a fix.
 If you do, please send it to bug-gnu-emacs@gnu.org so we can list it here.
 
 
-* Runtime problems specific to Mac OS X
-
-** On Mac OS X, file-name-case-insensitive-p may be unreliable
-
-The implementation of that function on Mac OS X uses pathconf with the
-_PC_CASE_SENSITIVE flag.  There have been reports that this use of
-pathconf does not work reliably.  If you have a problem, please
-recompile Emacs with -D DARWIN_OS_CASE_SENSITIVE_FIXME, and file a bug
-report saying whether this fixed your problem.
-
 * Build-time problems
 
 ** Configuration
diff --git a/src/fileio.c b/src/fileio.c
index 17659b6..c21056e 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2271,27 +2271,6 @@ file_name_case_insensitive_p (const char *filename)
     return res == 0;
 #endif
 
-  /* There have been reports that pathconf with _PC_CASE_SENSITIVE
-     does not work reliably on Mac OS X.  If you have a problem,
-     please recompile Emacs with -D DARWIN_OS_CASE_SENSITIVE_FIXME=1 or
-     -D DARWIN_OS_CASE_SENSITIVE_FIXME=2, and file a bug report saying
-     whether this fixed your problem.  */
-
-#ifdef DARWIN_OS_CASE_SENSITIVE_FIXME
-# ifdef VOL_CAP_FMT_CASE_SENSITIVE
-  {
-    struct attrlist alist = {.bitmapcount = ATTR_BIT_MAP_COUNT,
-			     .volattr = ATTR_VOL_INFO | ATTR_VOL_CAPABILITIES};
-    struct { uint32_t len; vol_capabilities_attr_t caps; } vcaps
-      __attribute__ ((aligned (4), packed));
-    int i = VOL_CAPABILITIES_FORMAT;
-    if (getattrlist (filename, &alist, &vcaps, sizeof vcaps, 0) == 0
-	&& (vcaps.caps.valid[i] & VOL_CAP_FMT_CASE_SENSITIVE))
-      return ! (vcaps.caps.capabilities[i] & VOL_CAP_FMT_CASE_SENSITIVE);
-  }
-# endif
-#endif
-
 #if defined CYGWIN || defined DOS_NT
   return true;
 #else
-- 
2.7.4