Add support for lcov 2.0

lcov 2.0 deprecates `--rc lcov_branch_coverage=1` for `--rc branch_coverage=1` and
gives an error when an exclude is used on a non existing directory.

I added a version check for lcov and removed the subprojects directory from the
exclusion list if it does not exist.

Fixes #11995

3 files changed, 32 insertions, 12 deletions

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index a994d7388..29883bac7 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -640,7 +640,7 @@ class NinjaBackend(backends.Backend):
             key = OptionKey('b_coverage')
             if (key in self.environment.coredata.options and
                     self.environment.coredata.options[key].value):
-                gcovr_exe, gcovr_version, lcov_exe, genhtml_exe, _ = environment.find_coverage_tools()
+                gcovr_exe, gcovr_version, lcov_exe, lcov_version, genhtml_exe, _ = environment.find_coverage_tools()
                 if gcovr_exe or (lcov_exe and genhtml_exe):
                     self.add_build_comment(NinjaComment('Coverage rules'))
                     self.generate_coverage_rules(gcovr_exe, gcovr_version)
diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index 7bd8c2ca6..2ba20548f 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -96,6 +96,20 @@ def detect_gcovr(min_version: str = '3.3', log: bool = False):
         return gcovr_exe, found
     return None, None
 
+def detect_lcov(log: bool = False):
+    lcov_exe = 'lcov'
+    try:
+        p, found = Popen_safe([lcov_exe, '--version'])[0:2]
+    except (FileNotFoundError, PermissionError):
+        # Doesn't exist in PATH or isn't executable
+        return None, None
+    found = search_version(found)
+    if p.returncode == 0 and found:
+        if log:
+            mlog.log('Found lcov-{} at {}'.format(found, quote_arg(shutil.which(lcov_exe))))
+        return lcov_exe, found
+    return None, None
+
 def detect_llvm_cov():
     tools = get_llvm_tool_names('llvm-cov')
     for tool in tools:
@@ -103,20 +117,18 @@ def detect_llvm_cov():
             return tool
     return None
 
-def find_coverage_tools() -> T.Tuple[T.Optional[str], T.Optional[str], T.Optional[str], T.Optional[str], T.Optional[str]]:
+def find_coverage_tools() -> T.Tuple[T.Optional[str], T.Optional[str], T.Optional[str], T.Optional[str], T.Optional[str], T.Optional[str]]:
     gcovr_exe, gcovr_version = detect_gcovr()
 
     llvm_cov_exe = detect_llvm_cov()
 
-    lcov_exe = 'lcov'
+    lcov_exe, lcov_version = detect_lcov()
     genhtml_exe = 'genhtml'
 
-    if not mesonlib.exe_exists([lcov_exe, '--version']):
-        lcov_exe = None
     if not mesonlib.exe_exists([genhtml_exe, '--version']):
         genhtml_exe = None
 
-    return gcovr_exe, gcovr_version, lcov_exe, genhtml_exe, llvm_cov_exe
+    return gcovr_exe, gcovr_version, lcov_exe, lcov_version, genhtml_exe, llvm_cov_exe
 
 def detect_ninja(version: str = '1.8.2', log: bool = False) -> T.List[str]:
     r = detect_ninja_command_and_version(version, log)
diff --git a/mesonbuild/scripts/coverage.py b/mesonbuild/scripts/coverage.py
index cb865d08d..4c0f81e8a 100644
--- a/mesonbuild/scripts/coverage.py
+++ b/mesonbuild/scripts/coverage.py
@@ -22,7 +22,7 @@ def coverage(outputs: T.List[str], source_root: str, subproject_root: str, build
     outfiles = []
     exitcode = 0
 
-    (gcovr_exe, gcovr_version, lcov_exe, genhtml_exe, llvm_cov_exe) = environment.find_coverage_tools()
+    (gcovr_exe, gcovr_version, lcov_exe, lcov_version, genhtml_exe, llvm_cov_exe) = environment.find_coverage_tools()
 
     # load config files for tools if available in the source tree
     # - lcov requires manually specifying a per-project config
@@ -35,6 +35,11 @@ def coverage(outputs: T.List[str], source_root: str, subproject_root: str, build
     else:
         lcov_config = []
 
+    if lcov_exe and mesonlib.version_compare(lcov_version, '>=2.0'):
+        lcov_exe_rc_branch_coverage = ['--rc', 'branch_coverage=1']
+    else:
+        lcov_exe_rc_branch_coverage = ['--rc', 'lcov_branch_coverage=1']
+
     gcovr_config = ['-e', re.escape(subproject_root)]
 
     # gcovr >= 4.2 requires a different syntax for out of source builds
@@ -90,6 +95,9 @@ def coverage(outputs: T.List[str], source_root: str, subproject_root: str, build
             initial_tracefile = covinfo + '.initial'
             run_tracefile = covinfo + '.run'
             raw_tracefile = covinfo + '.raw'
+            lcov_subpoject_exclude = []
+            if os.path.exists(subproject_root):
+                lcov_subpoject_exclude.append(os.path.join(subproject_root, '*'))
             if use_llvm_cov:
                 # Create a shim to allow using llvm-cov as a gcov tool.
                 if mesonlib.is_windows():
@@ -117,26 +125,26 @@ def coverage(outputs: T.List[str], source_root: str, subproject_root: str, build
                                    '--capture',
                                    '--output-file', run_tracefile,
                                    '--no-checksum',
-                                   '--rc', 'lcov_branch_coverage=1'] +
+                                   *lcov_exe_rc_branch_coverage] +
                                   lcov_config +
                                   gcov_tool_args)
             # Join initial and test results.
             subprocess.check_call([lcov_exe,
                                    '-a', initial_tracefile,
                                    '-a', run_tracefile,
-                                   '--rc', 'lcov_branch_coverage=1',
+                                   *lcov_exe_rc_branch_coverage,
                                    '-o', raw_tracefile] + lcov_config)
             # Remove all directories outside the source_root from the covinfo
             subprocess.check_call([lcov_exe,
                                    '--extract', raw_tracefile,
                                    os.path.join(source_root, '*'),
-                                   '--rc', 'lcov_branch_coverage=1',
+                                   *lcov_exe_rc_branch_coverage,
                                    '--output-file', covinfo] + lcov_config)
             # Remove all directories inside subproject dir
             subprocess.check_call([lcov_exe,
                                    '--remove', covinfo,
-                                   os.path.join(subproject_root, '*'),
-                                   '--rc', 'lcov_branch_coverage=1',
+                                   *lcov_subpoject_exclude,
+                                   *lcov_exe_rc_branch_coverage,
                                    '--output-file', covinfo] + lcov_config)
             subprocess.check_call([genhtml_exe,
                                    '--prefix', build_root,