From 5ca349f95d836a2a59aceaa42715349749a43865 Mon Sep 17 00:00:00 2001
From: Arvind Sankar <nivedita@alum.mit.edu>
Date: Mon, 22 Jun 2020 12:08:12 -0400
Subject: [PATCH] Fix check for sed --in-place

The test added in commit
  4313a5b4c51e ("Detect if sed supports --in-place")
doesn't work at least on my system (autoconfig-2.69).

The issue is that SED has already been found and cached before this
function is evaluated, with the result that the test is completely
skipped.

...
checking for a sed that does not truncate output... /usr/bin/sed
...
checking for sed --in-place... (cached) /usr/bin/sed

The first test is executed by libtool.m4. This looks to have been around
in libtool for at least 15 years or so, not sure why this was not
encountered at the time of the original commit.

Fix this by caching the value of the ac_inplace flag rather than the
path to SED. Also use $SED and add AC_REQUIRE to ensure that we use the
sed that was located by the standard configure test.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10493
---
 Makefile.am                       |  2 +-
 cmd/arcstat/Makefile.am           |  2 +-
 cmd/dbufstat/Makefile.am          |  2 +-
 config/always-sed.m4              | 22 +++++++++++-----------
 tests/test-runner/bin/Makefile.am |  2 +-
 5 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 3e2d6e4dc9..6ba5ac3880 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -89,7 +89,7 @@ all-local:
 	    ${top_builddir}/scripts/zfs-tests.sh -c
 
 dist-hook:
-	sed ${ac_inplace} -e 's/Release:[[:print:]]*/Release:      $(RELEASE)/' \
+	$(SED) ${ac_inplace} -e 's/Release:[[:print:]]*/Release:      $(RELEASE)/' \
 		$(distdir)/META
 
 if BUILD_LINUX
diff --git a/cmd/arcstat/Makefile.am b/cmd/arcstat/Makefile.am
index 4b79f4bdd0..a0728f9cec 100644
--- a/cmd/arcstat/Makefile.am
+++ b/cmd/arcstat/Makefile.am
@@ -8,6 +8,6 @@ dist_bin_SCRIPTS = arcstat
 #
 if USING_PYTHON_2
 install-exec-hook:
-	sed ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
+	$(SED) ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
 	    $(DESTDIR)$(bindir)/arcstat
 endif
diff --git a/cmd/dbufstat/Makefile.am b/cmd/dbufstat/Makefile.am
index 10c9fbabbf..f3b7ed809f 100644
--- a/cmd/dbufstat/Makefile.am
+++ b/cmd/dbufstat/Makefile.am
@@ -8,6 +8,6 @@ dist_bin_SCRIPTS = dbufstat
 #
 if USING_PYTHON_2
 install-exec-hook:
-	sed ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
+	$(SED) ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
 	    $(DESTDIR)$(bindir)/dbufstat
 endif
diff --git a/config/always-sed.m4 b/config/always-sed.m4
index b9c7afd63d..19633e118a 100644
--- a/config/always-sed.m4
+++ b/config/always-sed.m4
@@ -2,15 +2,15 @@ dnl #
 dnl # Set the flags used for sed in-place edits.
 dnl #
 AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_SED], [
-	ac_inplace=""
-	AC_CACHE_CHECK([for sed --in-place], [ac_cv_path_SED],
-		[AC_PATH_PROGS_FEATURE_CHECK([SED], [sed],
-			[[tmpfile=$(mktemp)
-			  echo foo > $tmpfile
-			  $ac_path_SED --in-place 's#foo#bar#' $tmpfile \
-			  && ac_cv_path_SED=$ac_path_SED
-			  rm $tmpfile]],
-			[ac_inplace="-i ''"])])
-	AS_IF([test "x$ac_inplace" = "x"], [ac_inplace="--in-place"])
-	AC_SUBST([ac_inplace])
+	AC_REQUIRE([AC_PROG_SED])dnl
+	AC_CACHE_CHECK([for sed --in-place], [ac_cv_inplace], [
+		tmpfile=$(mktemp conftest.XXX)
+		echo foo >$tmpfile
+		AS_IF([$SED --in-place 's#foo#bar#' $tmpfile 2>/dev/null],
+		      [ac_cv_inplace="--in-place"],
+		      [$SED -i '' 's#foo#bar#' $tmpfile 2>/dev/null],
+		      [ac_cv_inplace="-i ''"],
+		      [AC_MSG_ERROR([$SED does not support in-place])])
+	])
+	AC_SUBST([ac_inplace], [$ac_cv_inplace])
 ])
diff --git a/tests/test-runner/bin/Makefile.am b/tests/test-runner/bin/Makefile.am
index e7838e43d3..09032ba689 100644
--- a/tests/test-runner/bin/Makefile.am
+++ b/tests/test-runner/bin/Makefile.am
@@ -9,7 +9,7 @@ dist_pkgdata_SCRIPTS = \
 #
 if USING_PYTHON_2
 install-data-hook:
-	sed ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
+	$(SED) ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
 	    $(DESTDIR)$(pkgdatadir)/test-runner.py \
 	    $(DESTDIR)$(pkgdatadir)/zts-report.py
 endif