preserve readonly flag when saving and restoring magic flags

1 files changed, 20 insertions, 11 deletions

diff --git a/mg.c b/mg.c
index f7d3634c57..fb913259fd 100644
--- a/mg.c
+++ b/mg.c
@@ -77,8 +77,9 @@ void setegid(uid_t id);
 
 struct magic_state {
     SV* mgs_sv;
-    U32 mgs_flags;
     I32 mgs_ss_ix;
+    U32 mgs_magical;
+    bool mgs_readonly;
 };
 /* MGS is typedef'ed to struct magic_state in perl.h */
 
@@ -100,7 +101,8 @@ S_save_magic(pTHX_ I32 mgs_ix, SV *sv)
 
     mgs = SSPTR(mgs_ix, MGS*);
     mgs->mgs_sv = sv;
-    mgs->mgs_flags = SvMAGICAL(sv) | SvREADONLY(sv);
+    mgs->mgs_magical = SvMAGICAL(sv);
+    mgs->mgs_readonly = SvREADONLY(sv) != 0;
     mgs->mgs_ss_ix = PL_savestack_ix;   /* points after the saved destructor */
 
     SvMAGICAL_off(sv);
@@ -125,8 +127,9 @@ Perl_mg_magical(pTHX_ SV *sv)
     const MAGIC* mg;
     PERL_ARGS_ASSERT_MG_MAGICAL;
     PERL_UNUSED_CONTEXT;
+
+    SvMAGICAL_off(sv);
     if ((mg = SvMAGIC(sv))) {
-	SvRMAGICAL_off(sv);
 	do {
 	    const MGVTBL* const vtbl = mg->mg_virtual;
 	    if (vtbl) {
@@ -191,7 +194,7 @@ Perl_mg_get(pTHX_ SV *sv)
     dVAR;
     const I32 mgs_ix = SSNEW(sizeof(MGS));
     const bool was_temp = (bool)SvTEMP(sv);
-    int have_new = 0;
+    bool have_new = 0;
     MAGIC *newmg, *head, *cur, *mg;
     /* guard against sv having being freed midway by holding a private
        reference. */
@@ -216,21 +219,24 @@ Perl_mg_get(pTHX_ SV *sv)
     newmg = cur = head = mg = SvMAGIC(sv);
     while (mg) {
 	const MGVTBL * const vtbl = mg->mg_virtual;
+	MAGIC * const nextmg = mg->mg_moremagic;	/* it may delete itself */
 
 	if (!(mg->mg_flags & MGf_GSKIP) && vtbl && vtbl->svt_get) {
 	    CALL_FPTR(vtbl->svt_get)(aTHX_ sv, mg);
 
 	    /* guard against magic having been deleted - eg FETCH calling
 	     * untie */
-	    if (!SvMAGIC(sv))
+	    if (!SvMAGIC(sv)) {
+		(SSPTR(mgs_ix, MGS *))->mgs_magical = 0; /* recalculate flags */
 		break;
+	    }
 
-	    /* Don't restore the flags for this entry if it was deleted. */
+	    /* recalculate flags if this entry was deleted. */
 	    if (mg->mg_flags & MGf_GSKIP)
-		(SSPTR(mgs_ix, MGS *))->mgs_flags = 0;
+		(SSPTR(mgs_ix, MGS *))->mgs_magical = 0;
 	}
 
-	mg = mg->mg_moremagic;
+	mg = nextmg;
 
 	if (have_new) {
 	    /* Have we finished with the new entries we saw? Start again
@@ -247,6 +253,7 @@ Perl_mg_get(pTHX_ SV *sv)
 	    have_new = 1;
 	    cur = mg;
 	    mg  = newmg;
+	    (SSPTR(mgs_ix, MGS *))->mgs_magical = 0; /* recalculate flags */
 	}
     }
 
@@ -285,7 +292,7 @@ Perl_mg_set(pTHX_ SV *sv)
 	nextmg = mg->mg_moremagic;	/* it may delete itself */
 	if (mg->mg_flags & MGf_GSKIP) {
 	    mg->mg_flags &= ~MGf_GSKIP;	/* setting requires another read */
-	    (SSPTR(mgs_ix, MGS*))->mgs_flags = 0;
+	    (SSPTR(mgs_ix, MGS*))->mgs_magical = 0;
 	}
 	if (PL_localizing == 2 && !S_is_container_magic(mg))
 	    continue;
@@ -2977,8 +2984,10 @@ S_restore_magic(pTHX_ const void *p)
 	    sv_force_normal_flags(sv, 0);
 #endif
 
-	if (mgs->mgs_flags)
-	    SvFLAGS(sv) |= mgs->mgs_flags;
+	if (mgs->mgs_readonly)
+	    SvREADONLY_on(sv);
+	if (mgs->mgs_magical)
+	    SvFLAGS(sv) |= mgs->mgs_magical;
 	else
 	    mg_magical(sv);
 	if (SvGMAGICAL(sv)) {