dependencies: fix pcap-config which now errors on --version

The latest release of libpcap added argument validation to pcap-config,
but still doesn't support --version. The next version of libpcap will
support --version.

Add support for config-tool dependencies which expect to break on
--version, to fallback to an option that does not error out or print
version info, for sanity checking.

2 files changed, 18 insertions, 2 deletions

diff --git a/mesonbuild/dependencies/configtool.py b/mesonbuild/dependencies/configtool.py
index 8b7f1bb..1c8d730 100644
--- a/mesonbuild/dependencies/configtool.py
+++ b/mesonbuild/dependencies/configtool.py
@@ -31,6 +31,9 @@ class ConfigToolDependency(ExternalDependency):
     Takes the following extra keys in kwargs that it uses internally:
     :tools List[str]: A list of tool names to use
     :version_arg str: The argument to pass to the tool to get it's version
+    :skip_version str: The argument to pass to the tool to ignore its version
+        (if ``version_arg`` fails, but it may start accepting it in the future)
+        Because some tools are stupid and don't accept --version
     :returncode_value int: The value of the correct returncode
         Because some tools are stupid and don't return 0
     """
@@ -38,6 +41,7 @@ class ConfigToolDependency(ExternalDependency):
     tools: T.Optional[T.List[str]] = None
     tool_name: T.Optional[str] = None
     version_arg = '--version'
+    skip_version: T.Optional[str] = None
     __strip_version = re.compile(r'^[0-9][0-9.]+')
 
     def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any], language: T.Optional[str] = None):
@@ -89,7 +93,13 @@ class ConfigToolDependency(ExternalDependency):
             except (FileNotFoundError, PermissionError):
                 continue
             if p.returncode != returncode:
-                continue
+                if self.skip_version:
+                    # maybe the executable is valid even if it doesn't support --version
+                    p = Popen_safe(tool + [self.skip_version])[0]
+                    if p.returncode != returncode:
+                        continue
+                else:
+                    continue
 
             out = self._sanitize_version(out.strip())
             # Some tools, like pcap-config don't supply a version, but also
diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index d23eeee..07f4e9a 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -293,13 +293,19 @@ class PcapDependencyConfigTool(ConfigToolDependency):
     tools = ['pcap-config']
     tool_name = 'pcap-config'
 
+    # version 1.10.2 added error checking for invalid arguments
+    # version 1.10.3 will hopefully add actual support for --version
+    skip_version = '--help'
+
     def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any]):
         super().__init__(name, environment, kwargs)
         if not self.is_found:
             return
         self.compile_args = self.get_config_value(['--cflags'], 'compile_args')
         self.link_args = self.get_config_value(['--libs'], 'link_args')
-        self.version = self.get_pcap_lib_version()
+        if self.version is None:
+            # older pcap-config versions don't support this
+            self.version = self.get_pcap_lib_version()
 
     def get_pcap_lib_version(self) -> T.Optional[str]:
         # Since we seem to need to run a program to discover the pcap version,