Fix up GCC compiler detection in ManyConfigTests

.github/workflows/dev.yml

@@ -269,10 +269,7 @@ jobs:
     env:
       # Disallowing shadowing would be very spammy for unity builds, because the
       # same variable name can be used in multiple files.
-      # We disable format truncation/overflow because the heuristics used for
-      # these warnings are not very good, and are apparently affected by the
-      # inliner, which is used much less aggressively in unity builds.
-      CFLAGS_UNITY: "-Wno-shadow -Wno-format-truncation -Wno-format-overflow"
+      CFLAGS_UNITY: "-Wno-shadow"
     steps:
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -321,7 +318,7 @@ jobs:
 
       - name: Configure
         shell: msys2 {0}
-        run: cmake -G Ninja -DPCRE2_BUILD_PCRE2_16=ON -DPCRE2_BUILD_PCRE2_32=ON -DBUILD_SHARED_LIBS=ON -DBUILD_STATIC_LIBS=ON -DPCRE2_DEBUG=ON -DCMAKE_C_FLAGS="$CFLAGS_GCC_STYLE -Wno-format-truncation -Wno-format-overflow" -DCMAKE_COMPILE_WARNING_AS_ERROR=ON -DCMAKE_BUILD_TYPE=Release -B build
+        run: cmake -G Ninja -DPCRE2_BUILD_PCRE2_16=ON -DPCRE2_BUILD_PCRE2_32=ON -DBUILD_SHARED_LIBS=ON -DBUILD_STATIC_LIBS=ON -DPCRE2_DEBUG=ON -DCMAKE_C_FLAGS="$CFLAGS_GCC_STYLE" -DCMAKE_COMPILE_WARNING_AS_ERROR=ON -DCMAKE_BUILD_TYPE=Release -B build
 
       - name: Build
         shell: msys2 {0}
@@ -392,7 +389,7 @@ jobs:
           run: |
             set -e
             # TODO: Set -DCMAKE_COMPILE_WARNING_AS_ERROR=ON (there's currently a build failure on S390x)
-            cmake -G Ninja -DPCRE2_SUPPORT_JIT=ON -DPCRE2_BUILD_PCRE2_16=ON -DPCRE2_BUILD_PCRE2_32=ON -DBUILD_SHARED_LIBS=ON -DBUILD_STATIC_LIBS=ON -DPCRE2_DEBUG=ON -DCMAKE_C_FLAGS="$CFLAGS_GCC_STYLE -Wno-format-truncation -Wno-format-overflow" -DCMAKE_COMPILE_WARNING_AS_ERROR=OFF -DCMAKE_BUILD_TYPE=RelWithDebInfo -B build
+            cmake -G Ninja -DPCRE2_SUPPORT_JIT=ON -DPCRE2_BUILD_PCRE2_16=ON -DPCRE2_BUILD_PCRE2_32=ON -DBUILD_SHARED_LIBS=ON -DBUILD_STATIC_LIBS=ON -DPCRE2_DEBUG=ON -DCMAKE_C_FLAGS="$CFLAGS_GCC_STYLE" -DCMAKE_COMPILE_WARNING_AS_ERROR=OFF -DCMAKE_BUILD_TYPE=RelWithDebInfo -B build
             ninja -C build
             (cd build && ctest -j3 --output-on-failure)
 

maint/ManyConfigTests

@@ -110,12 +110,14 @@ tmp=/tmp/pcre2testing
 
 CFLAGS="-g"
 OFLAGS="-O0"
+CC="${CC:=cc}"
 ISGCC=0
 
 # If the compiler is gcc, add a lot of warning switches.
 
-cc --version >/tmp/pcre2ccversion 2>/dev/null
-if [ $? -eq 0 ] && grep GCC /tmp/pcre2ccversion >/dev/null; then
+CC_VER_OUTPUT=`printf '#ifdef __GNUC__\nGCC=yes\n#endif\n' | $CC -E -`
+if [ $? -eq 0 ] && (echo "$CC_VER_OUTPUT" | grep GCC=yes) >/dev/null; then
+  echo "Treating $CC as GCC"
   ISGCC=1
   CFLAGS="$CFLAGS -Wall"
   CFLAGS="$CFLAGS -Wextra"
@@ -137,10 +139,9 @@ if [ $? -eq 0 ] && grep GCC /tmp/pcre2ccversion >/dev/null; then
   CFLAGS="$CFLAGS -Wstrict-prototypes"
   CFLAGS="$CFLAGS -Warray-bounds"
   CFLAGS="$CFLAGS -Wformat-overflow=2"
-  CFLAGS="$CFLAGS -Wformat-truncation=2"
+  CFLAGS="$CFLAGS -Wformat-truncation=1"
   CFLAGS="$CFLAGS -Wdeclaration-after-statement"
 fi
-rm -f /tmp/pcre2ccversion
 
 # This function runs a single test with the set of configuration options that
 # are in $opts. The source directory must be set in srcdir. The function must
@@ -161,7 +162,7 @@ runtest()
 
   if [ $dummy -eq 1 ]; then return; fi
 
-  CFLAGS="$CFLAGS" \
+  CC="$CC" CFLAGS="$CFLAGS" \
     $srcdir/configure $opts >/dev/null 2>teststderrM
   if [ $? -ne 0 ]; then
     echo " "

src/pcre2grep.c

@@ -3440,16 +3440,18 @@ if (isdirectory(pathname))
     while ((nextfile = readdirectory(dir)) != NULL)
       {
       int frc;
-      size_t fnlength = strlen(pathname) + strlen(nextfile) + 2;
-      if (fnlength > FNBUFSIZ)
+      int prc;
+      if (strlen(pathname) + strlen(nextfile) + 2 > sizeof(childpath) ||
+        (prc = snprintf(childpath, sizeof(childpath), "%s%c%s", pathname,
+                        FILESEP, nextfile)) < 0 ||
+        prc >= (int)sizeof(childpath))
         {
         /* LCOV_EXCL_START - this is a "never" event */
         fprintf(stderr, "pcre2grep: recursive filename is too long\n");
         rc = 2;
         break;
         /* LCOV_EXCL_STOP */
         }
-      snprintf(childpath, sizeof(childpath), "%s%c%s", pathname, FILESEP, nextfile);
 
       /* If the realpath() function is available, we can try to prevent endless
       recursion caused by a symlink pointing to a parent directory (GitHub
@@ -3509,15 +3511,19 @@ if (iswild(pathname))
   while ((nextfile = readdirectory(dir)) != NULL)
     {
     int frc;
-    if (strlen(pathname) + strlen(nextfile) + 1 > sizeof(buffer))
+    int prc;
+    if (strlen(pathname) + strlen(nextfile) + 1 > sizeof(buffer) ||
+      (prc = snprintf(buffer, sizeof(buffer), "%s%s", pathname,
+                      nextfile)) < 0 ||
+      prc >= (int)sizeof(buffer))
       {
       /* LCOV_EXCL_START - this is a "never" event */
       fprintf(stderr, "pcre2grep: wildcard filename is too long\n");
       rc = 2;
       break;
       /* LCOV_EXCL_STOP */
       }
-    snprintf(buffer, sizeof(buffer), "%s%s", pathname, nextfile);
+
     frc = grep_or_recurse(buffer, dir_recurse, FALSE);
     if (frc > 1) rc = frc;
      else if (frc == 0 && rc == 1) rc = 0;
@@ -4064,10 +4070,10 @@ for (i = 1; i < argc; i++)
           (int)strlen(arg) : (int)(argequals - arg);
 
         if ((ret = snprintf(buff1, sizeof(buff1), "%.*s", baselen, op->long_name),
-             ret < 0 || ret > (int)sizeof(buff1)) ||
+             ret < 0 || ret >= (int)sizeof(buff1)) ||
             (ret = snprintf(buff2, sizeof(buff2), "%s%.*s", buff1,
                      fulllen - baselen - 2, opbra + 1),
-             ret < 0 || ret > (int)sizeof(buff2)))
+             ret < 0 || ret >= (int)sizeof(buff2)))
           {
           /* LCOV_EXCL_START - this is a "never" event */
           fprintf(stderr, "pcre2grep: Buffer overflow when parsing %s option\n",