Fix macro scoping level on re-entry from %[] expresssion (#2354)

This is the same issue as commit 1767bc4fd8
was with Lua, and so the same fix works: restore the nesting level
from the macro context when re-entering macro engine from %[]
expression. Analysis and suggested fix by Michael Schroeder,
reproducer from Miro Hrončok.

Add tests for both %[] and %{expr:...}, although the latter isn't
affected because the expression is macro-expanded beforehand.

Fixes: #2354

rpmio/macro.c

@@ -58,8 +58,8 @@ struct rpmMacroEntry_s {
 struct rpmMacroContext_s {
     rpmMacroEntry *tab;  /*!< Macro entry table (array of pointers). */
     int n;      /*!< No. of macros. */
-    int depth;		 /*!< Depth tracking when recursing from Lua  */
-    int level;		 /*!< Scope level tracking when recursing from Lua  */
+    int depth;		 /*!< Depth tracking on external recursion */
+    int level;		 /*!< Scope level tracking when on external recursion */
     pthread_mutex_t lock;
     pthread_mutexattr_t lockattr;
 };
@@ -586,7 +586,16 @@ static void doExpressionExpansion(MacroBuf mb, const char * expr, size_t len)
 {
     char *buf = rstrndup(expr, len);
     char *result;
+    rpmMacroContext mc = mb->mc;
+    int odepth = mc->depth;
+    int olevel = mc->level;
+
+    mc->depth = mb->depth;
+    mc->level = mb->level;
     result = rpmExprStrFlags(buf, RPMEXPR_EXPAND);
+    mc->depth = odepth;
+    mc->level = olevel;
+
     if (!result) {
 	mb->error = 1;
 	goto exit;

tests/rpmmacro.at

@@ -526,6 +526,43 @@ runroot rpm \
 [])
 AT_CLEANUP
 
+AT_SETUP([expression macro level])
+AT_KEYWORDS([macros])
+AT_CHECK([[
+runroot rpm \
+	--define 'expopt(r) %[%{undefined yyy} ? "aa " : "bb "]%{-r:the -r option was set}%{!-r:the -r option was not set}' \
+	--eval '%expopt' \
+	--eval '%expopt -r' \
+	--define 'yyy 1' \
+	--eval '%expopt' \
+	--eval '%expopt -r'
+]],
+[0],
+[aa the -r option was not set
+aa the -r option was set
+bb the -r option was not set
+bb the -r option was set
+],
+[])
+
+AT_CHECK([[
+runroot rpm \
+	--define 'expopt(r) %{expr:%{undefined yyy} ? "aa " : "bb "}%{-r:the -r option was set}%{!-r:the -r option was not set}' \
+	--eval '%expopt' \
+	--eval '%expopt -r' \
+	--define 'yyy 1' \
+	--eval '%expopt' \
+	--eval '%expopt -r'
+]],
+[0],
+[aa the -r option was not set
+aa the -r option was set
+bb the -r option was not set
+bb the -r option was set
+],
+[])
+AT_CLEANUP
+
 AT_SETUP([short circuiting])
 AT_KEYWORDS([macros])
 AT_CHECK([