RustClippyLintBear: Linter support for Rust code

Closes coala#50

.gitignore

@@ -23,6 +23,7 @@ htmlcov
 *.egg-info
 .coverage.*
 src
+!tests/rust/test_*/src
 site
 .zanata-cache
 *.exe

bears/rust/RustClippyLintBear.py

@@ -0,0 +1,78 @@
+import json
+import shutil
+import os
+
+from coalib.bears.GlobalBear import GlobalBear
+from coalib.misc.Shell import run_shell_command
+from coalib.results.Result import Result
+from coalib.results.RESULT_SEVERITY import RESULT_SEVERITY
+from dependency_management.requirements.CargoRequirement import (
+        CargoRequirement)
+
+
+class RustClippyLintBear(GlobalBear):
+    LANGUAGES = {'Rust'}
+    AUTHORS = {'The coala developers'}
+    AUTHORS_EMAILS = {'[email protected]'}
+    LICENSE = 'AGPL-3.0'
+    CAN_DETECT = {
+        'Formatting',
+        'Unused Code',
+        'Syntax',
+        'Unreachable Code',
+        'Smell',
+        'Code Simplification',
+    }
+    EXECUTABLE = 'cargo.exe' if os.name == 'nt' else 'cargo'
+    REQUIREMENTS = {
+        CargoRequirement('clippy')
+    }
+    SEVERITY_MAP = {
+        'warning': RESULT_SEVERITY.NORMAL,
+        'error': RESULT_SEVERITY.MAJOR,
+    }
+
+    def run(self):
+        args = ('clippy', '--quiet', '--color', 'never',
+                '--', '-Z', 'unstable-options',
+                '--error-format', 'json',
+                '--test')
+        # In the future, we might want to use --manifest-path, which
+        # should point to the Cargo.toml file, instead of relying on
+        # the config directory.
+        # Currently bugged:
+        # https://github.com/Manishearth/rust-clippy/issues/1611
+
+        _, stderr_output = run_shell_command(
+            (self.EXECUTABLE,) + args,
+            cwd=self.get_config_dir(),
+            universal_newlines=True)
+
+        # Rust outputs \n's, instead of the system default.
+        for line in stderr_output.split('\n'):
+            # cargo still outputs some text, even when in quiet mode,
+            # when a project does not build. We treat it as
+            # a major concern.
+            if line.startswith('error: Could not compile '):
+                yield Result(
+                        origin=self.__class__.__name__,
+                        message=line,
+                        severity=RESULT_SEVERITY.MAJOR)
+                continue
+            if not line:
+                continue
+            if line.startswith('To learn more, run the command again'):
+                continue
+            yield self.new_result(json.loads(line))
+
+    def new_result(self, issue):
+        span = issue['spans'][0]
+        return Result.from_values(
+                origin=self.__class__.__name__,
+                message=issue['message'],
+                file=span['file_name'],
+                line=span['line_start'],
+                end_line=span['line_end'],
+                column=span['column_start'],
+                end_column=span['column_end'],
+                severity=self.SEVERITY_MAP[issue['level']])

tests/rust/.gitignore

@@ -0,0 +1,2 @@
+target
+Cargo.lock

tests/rust/RustClippyLintBearTest.py

@@ -0,0 +1,41 @@
+import unittest
+import shutil
+import os
+from queue import Queue
+from shutil import which
+from unittest.case import skipIf
+
+from coalib.settings.Section import Section
+
+from bears.rust.RustClippyLintBear import RustClippyLintBear
+
+
+@skipIf(which('cargo') is None, 'Cargo is not installed')
+class RustClippyLintBearTest(unittest.TestCase):
+
+    def setUp(self):
+        self.section = Section('name')
+        self.queue = Queue()
+        self.file_dict = {}
+        self.uut = RustClippyLintBear(self.file_dict, self.section, self.queue)
+
+    def change_directory(self, directory_name):
+        test_path = os.path.abspath(os.path.join(os.path.dirname(__file__),
+                                                 directory_name))
+        os.chdir(test_path)
+
+    def set_config_dir(self, directory):
+        # Work around https://github.com/coala/coala/issues/3867
+        test_path = os.path.abspath(os.path.join(
+            os.path.dirname(__file__), directory))
+        self.uut.get_config_dir = lambda *args, **kwargs: test_path
+
+    def test_ok_source(self):
+        self.set_config_dir('test_ok')
+        results = list(self.uut.run())
+        self.assertTrue(len(results) == 0)
+
+    def test_bad_source(self):
+        self.set_config_dir('test_bad')
+        results = list(self.uut.run())
+        self.assertTrue(len(results) >= 3)

tests/rust/test_bad/Cargo.toml

@@ -0,0 +1,5 @@
+[package]
+name = "coala_test_files"
+version = "0.1.0"
+
+[dependencies]

tests/rust/test_bad/src/lib.rs

@@ -0,0 +1,24 @@
+// This function should trigger unused code (warning level)
+fn testssss() {
+    // This comparison should trigger a `deny` level lint
+    let mut x: f64 = 0.0;
+    if x == std::f64::NAN {
+    }
+    x += 1.; // Triggers allow style lint
+    println!("{}", x);
+}
+
+
+// We test whether bad code is found in (unit) tests
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        let x = Some(1u8);
+        // This match triggers a `warning` level lint
+        match x {
+            Some(y) => println!("{:?}", y),
+            _ => ()
+        }
+    }
+}

tests/rust/test_ok/Cargo.toml

@@ -0,0 +1,5 @@
+[package]
+name = "coala_test_files"
+version = "0.1.0"
+
+[dependencies]

tests/rust/test_ok/src/lib.rs

@@ -0,0 +1,3 @@
+#[test]
+fn it_works() {
+}