ktest: Add a --dry-run mode

When working on a ktest configuration, it is often useful to inspect the
final option values after includes, defaults, per-test overrides, and
variable expansion have been applied, without actually starting a test run.

Add a --dry-run option that reads the configuration, prints the test
preamble using resolved option values, and exits before opening LOG_FILE or
executing any test logic.

This is useful for debugging ktest configurations and for scripts that need
to validate the final resolved settings without triggering side effects.

Cc: John Hawley <warthog9@eaglescrag.net>
Cc: Andrea Righi <arighi@nvidia.com>
Cc: Marcos Paulo de Souza <mpdesouza@suse.com>
Cc: Matthieu Baerts <matttbe@kernel.org>
Cc: Fernando Fernandez Mancera <fmancera@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Link: https://patch.msgid.link/20260307-ktest-fixes-v1-9-565d412f4925@suse.com
Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/tools/testing/ktest/ktest.pl b/tools/testing/ktest/ktest.pl
index 8962857ce4a638460e17d7ba32d25c35afa44732..de99b82d16ad3e3bc285c009c173907e3944a17c 100755 (executable)
--- a/tools/testing/ktest/ktest.pl
+++ b/tools/testing/ktest/ktest.pl
@@ -85,6 +85,7 @@ my %default = (
 );
 
 my $test_log_start = 0;
+my $dry_run = 0;
 
 my $ktest_config = "ktest.conf";
 my $version;
@@ -587,7 +588,7 @@ sub end_monitor;
 sub wait_for_monitor;
 
 sub _logit {
-    if (defined($opt{"LOG_FILE"})) {
+    if (defined($opt{"LOG_FILE"}) && defined(fileno(LOG))) {
        print LOG @_;
     }
 }
@@ -1365,6 +1366,9 @@ sub read_config {
            print "$option\n";
        }
        print "Set IGNORE_UNUSED = 1 to have ktest ignore unused variables\n";
+       if ($dry_run) {
+           return;
+       }
        if (!read_yn "Do you want to continue?") {
            exit -1;
        }
@@ -4249,6 +4253,53 @@ sub set_test_option {
     return eval_option($name, $option, $i);
 }
 
+sub print_test_preamble {
+    my ($resolved) = @_;
+
+    doprint "\n\nSTARTING AUTOMATED TESTS\n\n";
+
+    for (my $i = 0, my $repeat = 1; $i <= $opt{"NUM_TESTS"}; $i += $repeat) {
+
+       if (!$i) {
+           doprint "DEFAULT OPTIONS:\n";
+       } else {
+           doprint "\nTEST $i OPTIONS";
+           if (defined($repeat_tests{$i})) {
+               $repeat = $repeat_tests{$i};
+               doprint " ITERATE $repeat";
+           }
+           doprint "\n";
+       }
+
+       foreach my $option (sort keys %opt) {
+           my $value;
+
+           if ($option =~ /\[(\d+)\]$/) {
+               next if ($i != $1);
+
+               if ($resolved) {
+                   my $name = $option;
+                   $name =~ s/\[\d+\]$//;
+                   $value = set_test_option($name, $i);
+               } else {
+                   $value = $opt{$option};
+               }
+           } else {
+               next if ($i);
+
+               if ($resolved) {
+                   $value = set_test_option($option, 0);
+               } else {
+                   $value = $opt{$option};
+               }
+           }
+
+           $value = "" if (!defined($value));
+           doprint "$option = $value\n";
+       }
+    }
+}
+
 sub find_mailer {
     my ($mailer) = @_;
 
@@ -4348,6 +4399,8 @@ ktest.pl version: $VERSION
                     Sets global BUILD_NOCLEAN to 1
                 -D TEST_TYPE[2]=build
                     Sets TEST_TYPE of test 2 to "build"
+       --dry-run
+                Print resolved test options and exit without running tests.
 
                It can also override all temp variables.
                  -D USE_TEMP_DIR:=1
@@ -4379,6 +4432,9 @@ while ( $#ARGV >= 0 ) {
        } else {
            $command_vars[$#command_vars + 1] = $val;
        }
+    } elsif ( $ARGV[0] eq "--dry-run" ) {
+       $dry_run = 1;
+       shift;
     } elsif ( $ARGV[0] eq "-h" ) {
        die_usage;
     } else {
@@ -4427,6 +4483,11 @@ EOF
 }
 read_config $ktest_config;
 
+if ($dry_run) {
+    print_test_preamble 1;
+    exit 0;
+}
+
 if (defined($opt{"LOG_FILE"})) {
     $opt{"LOG_FILE"} = set_test_option("LOG_FILE", 1);
 }
@@ -4458,31 +4519,7 @@ if (defined($opt{"LOG_FILE"})) {
     LOG->autoflush(1);
 }
 
-doprint "\n\nSTARTING AUTOMATED TESTS\n\n";
-
-for (my $i = 0, my $repeat = 1; $i <= $opt{"NUM_TESTS"}; $i += $repeat) {
-
-    if (!$i) {
-       doprint "DEFAULT OPTIONS:\n";
-    } else {
-       doprint "\nTEST $i OPTIONS";
-       if (defined($repeat_tests{$i})) {
-           $repeat = $repeat_tests{$i};
-           doprint " ITERATE $repeat";
-       }
-       doprint "\n";
-    }
-
-    foreach my $option (sort keys %opt) {
-       if ($option =~ /\[(\d+)\]$/) {
-           next if ($i != $1);
-       } else {
-           next if ($i);
-       }
-
-       doprint "$option = $opt{$option}\n";
-    }
-}
+print_test_preamble 0;
 
 $SIG{INT} = qw(cancel_test);