Fix up GCC compiler detection in ManyConfigTests (#670)

Also, add fixes/suppressions for the inevitable warnings that have appeared due to the CI job not running with warnings.

.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

@@ -113,10 +113,11 @@ OFLAGS="-O0"
 CC="${CC:=cc}"
 ISGCC=0
 
-# If the compiler is gcc, add a lot of warning switches.
+# If the compiler is GCC or Clang, 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"
@@ -138,10 +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
@@ -162,7 +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/pcre2_compile.c

@@ -8115,6 +8115,7 @@ for (;; pptr++)
       cb->external_flags |= PCRE2_HASBKC;  /* Record */
 #if PCRE2_CODE_UNIT_WIDTH == 32
       meta_arg = OP_ALLANY;
+      (void)utf; /* Avoid compiler warning. */
 #else
       if (!utf) meta_arg = OP_ALLANY;
 #endif

src/pcre2_compile_class.c

@@ -524,6 +524,9 @@ if (xoptions & PCRE2_EXTRA_CASELESS_RESTRICT)
 
 if (xoptions & PCRE2_EXTRA_TURKISH_CASING)
   class_options |= PARSE_CLASS_TURKISH_UTF;
+#else
+(void)options;   /* Avoid compiler warning. */
+(void)xoptions;  /* Avoid compiler warning. */
 #endif
 
 /* Compute required space for the range. */
@@ -904,6 +907,10 @@ uint8_t *classbits = cb->classbits.classbits;
 uint32_t c, byte_start, byte_end;
 uint32_t classbits_end = (end <= 0xff ? end : 0xff);
 
+#ifndef SUPPORT_UNICODE
+(void)xoptions; /* Avoid compiler warning. */
+#endif
+
 /* If caseless matching is required, scan the range and process alternate
 cases. In Unicode, there are 8-bit characters that have alternate cases that
 are greater than 255 and vice-versa (though these may be ignored if caseless
@@ -1079,6 +1086,10 @@ BOOL utf = FALSE;
 uint32_t xclass_props;
 PCRE2_UCHAR *class_uchardata;
 class_ranges* cranges;
+#else
+(void)has_bitmap;    /* Avoid compiler warning. */
+(void)errorcodeptr;  /* Avoid compiler warning. */
+(void)lengthptr;     /* Avoid compiler warning. */
 #endif
 
 /* If an XClass contains a negative special such as \S, we need to flip the

src/pcre2_jit_char_inc.h

@@ -519,6 +519,8 @@ BOOL has_cmov, last_range_set;
 sljit_u32 category_list = 0;
 sljit_u32 items;
 int typereg = TMP1;
+#else
+(void)c; /* Avoid compiler warning. */
 #endif /* SUPPORT_UNICODE */
 
 SLJIT_ASSERT(common->locals_size >= SSIZE_OF(sw));

src/pcre2_match.c

@@ -365,6 +365,10 @@ PCRE2_SIZE length;
 PCRE2_SPTR eptr;
 PCRE2_SPTR eptr_start;
 
+#ifndef SUPPORT_UNICODE
+(void)caseopts; /* Avoid compiler warning. */
+#endif
+
 /* Deal with an unset group. The default is no match, but there is an option to
 match an empty string. */
 

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",