[PATCH] ninjatool: rebuild multi-output targets if outputs are missing

[Paolo Bonzini <pbonzini@redhat.com>]

The "stamp file trick" used to group targets of a single multi-output rule
prevents the user from deleting one such target in order to force its
rebuild.  Doing so will not touch the stamp file, and therefore only
the dummy ":" command will be executed.

With this patch, ninjatool writes rules that force-rebuild the stamp
file if any of its outputs are missing.  Rebuilding the missing
target therefore causes the stamp file to be rebuilt too.

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 scripts/ninjatool.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/scripts/ninjatool.py b/scripts/ninjatool.py
index 627a1cab45..6f0e35c727 100755
--- a/scripts/ninjatool.py
+++ b/scripts/ninjatool.py
@@ -908,6 +908,9 @@ class Ninja2Make(NinjaParserEventsWithVars):
             else:
                 stamp = '%s@%s.stamp' % (rule, sha1_text(targets)[0:11])
             self.print('%s: %s; @:' % (targets, stamp))
+            self.print('ifneq (%s, $(wildcard %s))' % (targets, targets))
+            self.print('.PHONY: %s' % (stamp, ))
+            self.print('endif')
             self.print('%s: %s | %s; ${ninja-command-restat}' % (stamp, inputs, orderonly))
             self.rule_targets[rule].append(stamp)
             self.stamp_targets[rule].append(stamp)
-- 
2.26.2