INTERFACE_SOURCES: Fix per-config link libs on multi-config generators

In multi-config generators we memoize the computed set of source files
for a target to avoid repeating the computation when the set does not
depend on the configuration.  We already track whether generator
expressions in `SOURCES` or `INTERFACE_SOURCES` reference the
configuration (`$<CONFIG:...>`).  However, we previously forgot to track
whether the set of libraries whose `INTERFACE_SOURCES` are considered
depends on the configuration.  This caused multi-config generators to
use the first configuration's set of sources for all configurations
in cases such as

    target_link_libraries(tgt PRIVATE $<$<CONFIG:Debug>:iface_debug>)

where the `iface_debug` target has `INTERFACE_SOURCES`.

Fix this by also tracking config-dependence of the list of libraries for
evaluation of the list of source files.

Fixes: #20683

1 files changed, 7 insertions, 1 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index d253bc7..a44126c 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -241,6 +241,7 @@ EvaluatedTargetPropertyEntry EvaluateTargetPropertyEntry(
 struct EvaluatedTargetPropertyEntries
 {
   std::vector<EvaluatedTargetPropertyEntry> Entries;
+  bool HadContextSensitiveCondition = false;
 };
 
 EvaluatedTargetPropertyEntries EvaluateTargetPropertyEntries(
@@ -1251,6 +1252,9 @@ std::string cmGeneratorTarget::EvaluateInterfaceProperty(
 
   if (cmLinkInterfaceLibraries const* iface = this->GetLinkInterfaceLibraries(
         context->Config, headTarget, usage_requirements_only)) {
+    context->HadContextSensitiveCondition =
+      context->HadContextSensitiveCondition ||
+      iface->HadContextSensitiveCondition;
     for (cmLinkItem const& lib : iface->Libraries) {
       // Broken code can have a target in its own link interface.
       // Don't follow such link interface entries so as not to create a
@@ -1378,6 +1382,7 @@ void AddInterfaceEntries(cmGeneratorTarget const* headTarget,
 {
   if (cmLinkImplementationLibraries const* impl =
         headTarget->GetLinkImplementationLibraries(config)) {
+    entries.HadContextSensitiveCondition = impl->HadContextSensitiveCondition;
     for (cmLinkImplItem const& lib : impl->Libraries) {
       if (lib.Target) {
         EvaluatedTargetPropertyEntry ee(lib, lib.Backtrace);
@@ -1404,6 +1409,7 @@ void AddObjectEntries(cmGeneratorTarget const* headTarget,
 {
   if (cmLinkImplementationLibraries const* impl =
         headTarget->GetLinkImplementationLibraries(config)) {
+    entries.HadContextSensitiveCondition = impl->HadContextSensitiveCondition;
     for (cmLinkImplItem const& lib : impl->Libraries) {
       if (lib.Target &&
           lib.Target->GetType() == cmStateEnums::OBJECT_LIBRARY) {
@@ -1436,7 +1442,7 @@ bool processSources(cmGeneratorTarget const* tgt,
 {
   cmMakefile* mf = tgt->Target->GetMakefile();
 
-  bool contextDependent = false;
+  bool contextDependent = entries.HadContextSensitiveCondition;
 
   for (EvaluatedTargetPropertyEntry& entry : entries.Entries) {
     if (entry.ContextDependent) {