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-rw-r--r--libbuild2/adhoc-rule-buildscript.cxx26
-rw-r--r--libbuild2/build/script/parser.cxx4
-rw-r--r--libbuild2/cc/compile-rule.cxx27
-rw-r--r--libbuild2/context.hxx17
4 files changed, 66 insertions, 8 deletions
diff --git a/libbuild2/adhoc-rule-buildscript.cxx b/libbuild2/adhoc-rule-buildscript.cxx
index b125ac5..e3ed0a4 100644
--- a/libbuild2/adhoc-rule-buildscript.cxx
+++ b/libbuild2/adhoc-rule-buildscript.cxx
@@ -1207,9 +1207,11 @@ namespace build2
}
// Note that in case of dry run we will have an incomplete (but valid)
- // database which will be updated on the next non-dry run.
+ // database which will be updated on the next non-dry run. Except that
+ // we may still end up performing a non-dry-run update due to update
+ // during match or load.
//
- if (!update || ctx.dry_run_option)
+ if (!update /*|| ctx.dry_run_option*/)
dd.close (false /* mtime_check */);
else
mdb->dd = dd.close_to_reopen ();
@@ -1246,8 +1248,24 @@ namespace build2
md->deferred_failure);
}
- if (update && dd.reading () && !ctx.dry_run_option)
- dd.touch = timestamp_unknown;
+ // Update depdb timestamp if nothing changed. Failed that, we will keep
+ // re-validating the information store in depdb (see similar logic in
+ // cc::compile_rule).
+ //
+ if (update && dd.reading ())
+ {
+ // What will happen if dry_run_option is true but we still end up
+ // performing a non-dry-run update due to update during match or
+ // load? In this case the target will become up-to-date and we will
+ // keep re-validating the cache until the depdb will get touched due
+ // to other reasons, which would be bad. So it feels like the least
+ // bad option is to keep re-touching the database on dry-run.
+ //
+#if 0
+ if (!ctx.dry_run_option)
+#endif
+ dd.touch = timestamp_unknown;
+ }
dd.close (false /* mtime_check */);
diff --git a/libbuild2/build/script/parser.cxx b/libbuild2/build/script/parser.cxx
index 3ecf23d..c9193ff 100644
--- a/libbuild2/build/script/parser.cxx
+++ b/libbuild2/build/script/parser.cxx
@@ -2501,6 +2501,10 @@ namespace build2
//
auto fail = [this, what, &ctx] (const auto& f) -> optional<bool>
{
+ // Note that this test will give a false negative if this target
+ // ends up being updated during load or match. At least it's
+ // conservative.
+ //
bool df (!ctx.match_only && !ctx.dry_run_option);
diag_record dr;
diff --git a/libbuild2/cc/compile-rule.cxx b/libbuild2/cc/compile-rule.cxx
index 29a26b5..c8955bc 100644
--- a/libbuild2/cc/compile-rule.cxx
+++ b/libbuild2/cc/compile-rule.cxx
@@ -1544,8 +1544,20 @@ namespace build2
// to keep re-validating the file on every subsequent dry-run as well
// on the real run).
//
- if (u && dd.reading () && !ctx.dry_run_option)
- dd.touch = timestamp_unknown;
+ if (u && dd.reading ())
+ {
+ // What will happen if dry_run_option is true but we still end up
+ // performing a non-dry-run update due to update during match or
+ // load? In this case the target will become up-to-date and we will
+ // keep re-validating the cache until the depdb will get touched due
+ // to other reasons, which would be bad. So it feels like the least
+ // bad option is to keep re-touching the database on dry-run.
+ //
+#if 0
+ if (!ctx.dry_run_option)
+#endif
+ dd.touch = timestamp_unknown;
+ }
dd.close (false /* mtime_check */);
md.dd = move (dd.path);
@@ -4042,6 +4054,10 @@ namespace build2
//
auto fail = [&ctx] (const auto& h) -> optional<bool>
{
+ // Note that this test will give a false negative if this target
+ // ends up being updated during load or match. At least it's
+ // conservative.
+ //
bool df (!ctx.match_only && !ctx.dry_run_option);
diag_record dr;
@@ -4104,7 +4120,6 @@ namespace build2
this] (path hp, path bp, timestamp mt) -> optional<bool>
{
context& ctx (t.ctx);
- bool df (!ctx.match_only && !ctx.dry_run_option);
const file* ht (
enter_header (a, bs, t, li,
@@ -4113,6 +4128,12 @@ namespace build2
if (ht == nullptr) // hp is still valid.
{
+ // Note that this test will give a false negative if this target
+ // ends up being updated during load or match. At least it's
+ // conservative.
+ //
+ bool df (!ctx.match_only && !ctx.dry_run_option);
+
diag_record dr;
dr << error << "header " << hp << " not found and no rule to "
<< "generate it";
diff --git a/libbuild2/context.hxx b/libbuild2/context.hxx
index 81ac970..46dbfaa 100644
--- a/libbuild2/context.hxx
+++ b/libbuild2/context.hxx
@@ -230,6 +230,10 @@ namespace build2
// Match only flag/level (see --{load,match}-only but also dist).
//
+ // See also dry_run, which is in some sense a weaker version of match-
+ // only: the target is executed but nothing is actually being done (unless
+ // executed during match or load, that is).
+ //
optional<match_only_level> match_only;
// Skip booting external modules flag (see --no-external-modules).
@@ -263,11 +267,22 @@ namespace build2
//
// Note also that sometimes it makes sense to do a bit more than
// absolutely necessary or to discard information in order to keep the
- // rule logic sane. And some rules may choose to ignore this flag
+ // rule logic sane. And some rules may choose to ignore this flag
// altogether. In this case, however, the rule should be careful not to
// rely on functions (notably from filesystem) that respect this flag in
// order not to end up with a job half done.
//
+ // Finally, sometimes you may need to know during match whether there will
+ // be a non-dry-run execute and use the dry_run_option for that. This can
+ // be problematic because even when dry_run_option is true, the target may
+ // end up being executed in the non-dry-run mode during load or match. As
+ // a result, any logic that is based on dry_run_option should be capable
+ // of functioning correctly in the non-dry-run execute.
+ //
+ // See also match_only, which is in some sense a stronger version of
+ // dry-run: the target is not executed at all, again, unless during match
+ // or load.
+ //
bool dry_run = false;
bool dry_run_option;