[src/trunk]: src/usr.bin/make/unit-tests tests/make: document inconsistencies...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c98322bccae4
branches:  trunk
changeset: 1029226:c98322bccae4
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Dec 28 00:56:16 2021 +0000

description:
tests/make: document inconsistencies between '!=' and '::!='

Found while trying to make the error messages from Cmd_Exec more
detailed.

diffstat:

 distrib/sets/lists/tests/mi                     |   4 ++-
 usr.bin/make/unit-tests/Makefile                |   3 +-
 usr.bin/make/unit-tests/varmod-assign-shell.exp |   5 +++
 usr.bin/make/unit-tests/varmod-assign-shell.mk  |  32 +++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 2 deletions(-)

diffs (80 lines):

diff -r 61676984523b -r c98322bccae4 distrib/sets/lists/tests/mi
--- a/distrib/sets/lists/tests/mi       Tue Dec 28 00:37:16 2021 +0000
+++ b/distrib/sets/lists/tests/mi       Tue Dec 28 00:56:16 2021 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: mi,v 1.1180 2021/12/23 11:05:58 rillig Exp $
+# $NetBSD: mi,v 1.1181 2021/12/28 00:56:16 rillig Exp $
 #
 # Note: don't delete entries from here - mark them as "obsolete" instead.
 #
@@ -5967,6 +5967,8 @@
 ./usr/tests/usr.bin/make/unit-tests/varfind.mk                                 tests-usr.bin-tests     compattestfile,atf
 ./usr/tests/usr.bin/make/unit-tests/varmisc.exp                                        tests-usr.bin-tests     compattestfile,atf
 ./usr/tests/usr.bin/make/unit-tests/varmisc.mk                                 tests-usr.bin-tests     compattestfile,atf
+./usr/tests/usr.bin/make/unit-tests/varmod-assign-shell.exp                    tests-usr.bin-tests     compattestfile,atf
+./usr/tests/usr.bin/make/unit-tests/varmod-assign-shell.mk                     tests-usr.bin-tests     compattestfile,atf
 ./usr/tests/usr.bin/make/unit-tests/varmod-assign.exp                          tests-usr.bin-tests     compattestfile,atf
 ./usr/tests/usr.bin/make/unit-tests/varmod-assign.mk                           tests-usr.bin-tests     compattestfile,atf
 ./usr/tests/usr.bin/make/unit-tests/varmod-defined.exp                         tests-usr.bin-tests     compattestfile,atf
diff -r 61676984523b -r c98322bccae4 usr.bin/make/unit-tests/Makefile
--- a/usr.bin/make/unit-tests/Makefile  Tue Dec 28 00:37:16 2021 +0000
+++ b/usr.bin/make/unit-tests/Makefile  Tue Dec 28 00:56:16 2021 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.291 2021/12/23 11:05:59 rillig Exp $
+# $NetBSD: Makefile,v 1.292 2021/12/28 00:56:17 rillig Exp $
 #
 # Unit tests for make(1)
 #
@@ -342,6 +342,7 @@
 TESTS+=                varmisc
 TESTS+=                varmod
 TESTS+=                varmod-assign
+TESTS+=                varmod-assign-shell
 TESTS+=                varmod-defined
 TESTS+=                varmod-edge
 TESTS+=                varmod-exclam-shell
diff -r 61676984523b -r c98322bccae4 usr.bin/make/unit-tests/varmod-assign-shell.exp
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/usr.bin/make/unit-tests/varmod-assign-shell.exp   Tue Dec 28 00:56:16 2021 +0000
@@ -0,0 +1,5 @@
+make: "varmod-assign-shell.mk" line 25: warning: "echo output; false" returned non-zero status
+make: "echo output; false" returned non-zero status
+DIRECT=output
+ASSIGNED=previous
+exit status 0
diff -r 61676984523b -r c98322bccae4 usr.bin/make/unit-tests/varmod-assign-shell.mk
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/usr.bin/make/unit-tests/varmod-assign-shell.mk    Tue Dec 28 00:56:16 2021 +0000
@@ -0,0 +1,32 @@
+# $NetBSD: varmod-assign-shell.mk,v 1.1 2021/12/28 00:56:17 rillig Exp $
+#
+# Tests for the variable modifier '::!=', which assigns the output of a shell
+# command to the variable, but only if the command exited successfully.  This
+# is different from the variable assignment operator '!=', which also assigns
+# when the shell command fails or crashes.
+#
+# The variable modifier '::!=' and its close relatives have been around since
+# var.c 1.45 from 2000-06-01.
+#
+# Before 2020.08.25.21.16.53, the variable modifier '::!=' had a bug for
+# unsuccessful commands, it put the previous value of the variable into the
+# error message instead of the command that was executed.  That's where the
+# counterintuitive error message 'make: "previous" returned non-zero status'
+# comes from.
+#
+# BUGS
+#      Even though the variable modifier '::!=' produces an error message,
+#      the exit status of make is still 0.
+#
+#      Having an error message instead of a warning like for the variable
+#      assignment operator '!=' is another unnecessary inconsistency.
+
+DIRECT=         previous
+DIRECT!=        echo output; false
+
+ASSIGNED=       previous
+_:=             ${ASSIGNED::!=echo output; false}
+
+all:
+       @echo DIRECT=${DIRECT:Q}
+       @echo ASSIGNED=${ASSIGNED:Q}