Merge #365

365: On-save check: Only call `cargo metadata` once. r=ehuss a=ehuss

Also fixes setting the toolchain when manually configured.

Co-authored-by: Eric Huss <[email protected]>

Author: bors[bot]

SyntaxCheckPlugin.py

@@ -163,15 +163,21 @@ def get_rustc_messages(self):
             print('Unknown setting for `rust_syntax_checking_method`: %r' % (method,))
             return -1
 
+        # Try to grab metadata only once. `target` is None since that's what
+        # we're trying to figure out.
+        toolchain = settings.get_computed(self.cwd, method, None, 'toolchain')
+        metadata = util.get_cargo_metadata(self.window, self.cwd, toolchain=toolchain)
+        if not metadata:
+            return -1
         td = target_detect.TargetDetector(self.window)
-        targets = td.determine_targets(self.triggered_file_name)
+        targets = td.determine_targets(self.triggered_file_name, metadata=metadata)
         if not targets:
             return -1
         rc = 0
         for (target_src, target_args) in targets:
             cmd = settings.get_command(method, command_info, self.cwd, self.cwd,
                 initial_settings={'target': ' '.join(target_args)},
-                force_json=True)
+                force_json=True, metadata=metadata)
             self.msg_rel_path = cmd['msg_rel_path']
             if (util.get_setting('rust_syntax_checking_include_tests', True) and
                 semver.match(cmd['rustc_version'], '>=1.23.0')):

rust/cargo_settings.py

@@ -353,7 +353,8 @@ def get_merged(self, settings_path, variant, target, key,
 
     def get_command(self, cmd_name, cmd_info,
                     settings_path, working_dir,
-                    initial_settings={}, force_json=False):
+                    initial_settings={}, force_json=False,
+                    metadata=None):
         """Generates the command arguments for running Cargo.
 
         :param cmd_name: The name of the command, the key used to select a
@@ -367,6 +368,8 @@ def get_command(self, cmd_name, cmd_info,
         :keyword initial_settings: Initial settings to inject which override
             all other settings.
         :keyword force_json: If True, will force JSON output.
+        :keyword metadata: Output from `get_cargo_metadata`. If None, will run
+            it manually.
 
         :Returns: A dictionary with the keys:
             - `command`: The command to run as a list of strings.
@@ -466,7 +469,8 @@ def expand(s):
         #
         # Starting in Rust 1.24, all messages and symbols are relative to the
         # workspace root instead of the package root.
-        metadata = util.get_cargo_metadata(self.window, working_dir, toolchain)
+        if metadata is None:
+            metadata = util.get_cargo_metadata(self.window, working_dir, toolchain)
         if metadata and 'workspace_root' in metadata:
             # 'workspace_root' key added in 1.24.
             msg_rel_path = metadata['workspace_root']

rust/target_detect.py

@@ -15,11 +15,14 @@ class TargetDetector(object):
     def __init__(self, window):
         self.window = window
 
-    def determine_targets(self, file_name):
+    def determine_targets(self, file_name, metadata=None):
         """Detect the target/filters needed to pass to Cargo to compile
         file_name.
         Returns list of (target_src_path, target_command_line_args) tuples.
 
+        :keyword metadata: Output from `get_cargo_metadata`. If None, will run
+            it manually.
+
         :raises ProcessTerminatedError: Thread should shut down.
         """
         # Try checking for target match in settings.
@@ -28,13 +31,12 @@ def determine_targets(self, file_name):
             return result
 
         # Try a heuristic to detect the filename.
-        result = rust_proc.slurp_json(self.window,
-                                      'cargo metadata --no-deps'.split(),
-                                      cwd=os.path.dirname(file_name))
-        if not result:
-            return []
+        if metadata is None:
+            metadata = util.get_cargo_metadata(self.window, os.path.dirname(file_name))
+            if not metadata:
+                return []
         # Each "workspace" shows up as a separate package.
-        for package in result[0]['packages']:
+        for package in metadata['packages']:
             root_path = os.path.dirname(package['manifest_path'])
             targets = package['targets']
             # targets is list of dictionaries: