feat: Extend Apple Framework header support to #include

Follow-up to the earlier patch that added framework handling for
`__has_include`. This change updates `preprocess()` so that plain
`#include <Pkg/MyHdr.h>` also resolves to
`<Pkg.framework/Headers/MyHdr.h>` when present.

Tests:
- Add `appleFrameworkIncludeTest` to verify `#include` resolution.

Co-authored-by: Hans Johnson <hans-johnson@uiowa.edu>

Author: jcfr

simplecpp.cpp

@@ -3507,7 +3507,28 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
 
                 const bool systemheader = (inctok->str()[0] == '<');
                 const std::string header(inctok->str().substr(1U, inctok->str().size() - 2U));
-                const FileData *const filedata = cache.get(rawtok->location.file(), header, dui, systemheader, files, outputList).first;
+
+                // First, try normal resolution through the cache
+                const FileData * filedata = cache.get(rawtok->location.file(), header, dui, systemheader, files, outputList).first;
+
+                // Fallback: normal lookup failed. Use openHeader(...), which also handles Apple
+                // frameworks (e.g., "<Foo/Bar.h>" -> "<Foo.framework/Headers/Bar.h>").
+                // If openHeader(...) returns a resolved absolute path, load it via cache.get(...)
+                // with systemheader=false to treat it as a direct file (no system-header semantics)
+                // and outputList=nullptr to avoid emitting a duplicate "missing header" diagnostic
+                if (filedata == nullptr) {
+                    std::ifstream f;
+                    const std::string resolved =
+                        openHeader(f, dui, rawtok->location.file(), header, systemheader);
+                    if (!resolved.empty() && resolved != header) {
+                        filedata = cache.get(rawtok->location.file(),
+                                             resolved,
+                                             dui,
+                                             /*systemheader=*/ false,
+                                             files,
+                                             /*outputList*/ nullptr).first;
+                    }
+                }
                 if (filedata == nullptr) {
                     if (outputList) {
                         simplecpp::Output out(files);

test.cpp

@@ -2131,6 +2131,32 @@ static void circularInclude()
     ASSERT_EQUALS("", toString(outputList));
 }
 
+static void appleFrameworkIncludeTest()
+{
+    // This test checks Apple framework include handling.
+    //
+    // If -I /tmp/testFrameworks
+    // and we write:
+    //   #include <Foundation/Foundation.h>
+    //
+    // then simplecpp should find:
+    //   ./testsuite/Foundation.framework/Headers/Foundation.h
+    const char code[] = "#include <Foundation/Foundation.h>\n";
+    std::vector<std::string> files;
+    const simplecpp::TokenList rawtokens = makeTokenList(code, files, "sourcecode.cpp");
+    simplecpp::FileDataCache cache;
+    simplecpp::TokenList tokens2(files);
+    simplecpp::DUI dui;
+#ifdef SIMPLECPP_SOURCE_DIR
+    dui.includePaths.push_back(std::string(SIMPLECPP_SOURCE_DIR) + "/testsuite");
+#else
+    dui.includePaths.push_back("./testsuite");
+#endif
+    simplecpp::OutputList outputList;
+    simplecpp::preprocess(tokens2, rawtokens, files, cache, dui, &outputList);
+    ASSERT_EQUALS("", toString(outputList));
+}
+
 static void appleFrameworkHasIncludeTest()
 {
     const char code[] =
@@ -3389,6 +3415,7 @@ int main(int argc, char **argv)
     TEST_CASE(nestedInclude);
     TEST_CASE(systemInclude);
     TEST_CASE(circularInclude);
+    TEST_CASE(appleFrameworkIncludeTest);
     TEST_CASE(appleFrameworkHasIncludeTest);
 
     TEST_CASE(nullDirective1);