[Fontforge-devel] MergeFonts() changes some glyph names randomly.

[Aktado <ak...@us...>]

Using MergeFonts() procedure in FontForge scripting language on Linux,  
I get a warning message that says:
| The glyph named uniXXXX is mapped to U+YYYY.
|   But its name indicates it should be mapped to U+XXXX.
(The values of XXXX and YYYY vary each run.)

I think it occurs from double-free of sc->ttf_instrs.
In fvfonts.c, SplineCharCopy() function copies sc to nsc shallowly.  
nsc->ttf_instrs can be free'd in SCConvertLayerToOrder3(), and then
sc->ttf_instrs, which has the same address as nsc->ttf_instrs, is 
free'd in SplineCharFreeContent() again.

P.S.
I've heard 64-bit version of FontForge crashes with segfault on MacOS X,
perhaps in MergeFonts().  I guess this patch also remedies the problem, 
but don't see for myself.  



diff --git a/fontforge/fvfonts.c b/fontforge/fvfonts.c
--- a/fontforge/fvfonts.c
+++ b/fontforge/fvfonts.c
@@ -490,6 +490,7 @@
     int layer, lycopy;
 
     *nsc = *sc;		/* We copy the layers just below */
+    nsc->ttf_instrs = NULL; nsc->ttf_instrs_len = 0;
     nsc->layer_cnt = into==NULL?2:into->layer_cnt;
     nsc->layers = layers;
     lycopy = sc->layer_cnt>nsc->layer_cnt ? nsc->layer_cnt : sc->layer_cnt;
@@ -528,7 +529,8 @@
     nsc->anchor = AnchorPointsDuplicate(nsc->anchor,nsc);
     nsc->changed = true;
     nsc->dependents = NULL;		/* Fix up later when we know more */
-    if ( nsc->ttf_instrs_len!=0 ) {
+    if ( sc->ttf_instrs_len!=0 ) {
+	nsc->ttf_instrs_len = sc->ttf_instrs_len;
 	nsc->ttf_instrs = galloc(nsc->ttf_instrs_len);
 	memcpy(nsc->ttf_instrs,sc->ttf_instrs,nsc->ttf_instrs_len);
     }