Record compiler warning count in sketches report

This data can be useful for detecting an increase in compiler warnings.

When deltas reports are enabled, compiler warning count for the base ref compilation as well as the delta will be recorded in the report and the delta printed to the workflow run log.

Author: per1234

README.md

@@ -118,7 +118,7 @@ GitHub access token used to get information from the GitHub API. Only needed for
 
 ### `enable-deltas-report`
 
-Set to `true` to cause the action to determine the change in memory usage of the compiled sketches. If the workflow is triggered by a `pull_request` event, the comparison is between the pull request branch and the tip of the pull request's base branch. If the workflow is triggered by a `push` event, the comparison is between the pushed commit and its immediate parent. This may be used with the [`arduino/actions/libraries/report-size-deltas` action](https://github.com/arduino/actions/tree/master/libraries/report-size-deltas). Default `false`.
+Set to `true` to cause the action to determine the change in memory usage and compiler warnings of the compiled sketches. If the workflow is triggered by a `pull_request` event, the comparison is between the pull request branch and the tip of the pull request's base branch. If the workflow is triggered by a `push` event, the comparison is between the pushed commit and its immediate parent. This may be used with the [`arduino/actions/libraries/report-size-deltas` action](https://github.com/arduino/actions/tree/master/libraries/report-size-deltas). Default `false`.
 
 ## Example usage
 
@@ -133,7 +133,7 @@ Only compiling examples:
         version: 1.1.3
 ```
 
-Storing the memory usage change report as a [workflow artifact](https://help.github.com/en/actions/configuring-and-managing-workflows/persisting-workflow-data-using-artifacts):
+Storing the sketches compilation report report as a [workflow artifact](https://help.github.com/en/actions/configuring-and-managing-workflows/persisting-workflow-data-using-artifacts):
 ```yaml
 - uses: arduino/actions/libraries/compile-examples@master
   with:

action.yml

@@ -26,7 +26,7 @@ inputs:
     description: 'GitHub access token used to get information from the GitHub API. Only needed if you are using the size deltas report feature with a private repository.'
     default: ''
   enable-deltas-report:
-    description: 'Set to true to cause the action to determine the change in memory usage of the compiled sketches between the head and base refs of a PR and the immediate parent commit of a push'
+    description: 'Set to true to cause the action to determine the change in memory usage and compiler warnings of the compiled sketches between the head and base refs of a PR and the immediate parent commit of a push'
     default: false
 runs:
   using: 'docker'

compilesketches/compilesketches.py

@@ -92,6 +92,7 @@ class ReportKeys:
         commit_url = "commit_url"
         compilation_success = "compilation_success"
         sizes = "sizes"
+        warnings = "warnings"
         name = "name"
         absolute = "absolute"
         relative = "relative"
@@ -886,8 +887,13 @@ def get_sketch_report(self, compilation_result):
         compilation_result -- object returned by compile_sketch()
         """
         current_sizes = self.get_sizes_from_output(compilation_result=compilation_result)
+        current_warning_count = self.get_warning_count_from_output(compilation_result=compilation_result)
+
         previous_sizes = None
-        if self.do_deltas_report(compilation_result=compilation_result, current_sizes=current_sizes):
+        previous_warning_count = None
+        if self.do_deltas_report(compilation_result=compilation_result,
+                                 current_sizes=current_sizes,
+                                 current_warnings=current_warning_count):
             # Get data for the sketch at the base ref
             # Get the head ref
             repository = git.Repo(path=os.environ["GITHUB_WORKSPACE"])
@@ -904,13 +910,16 @@ def get_sketch_report(self, compilation_result):
             repository.git.checkout(original_git_ref, recurse_submodules=True)
 
             previous_sizes = self.get_sizes_from_output(compilation_result=previous_compilation_result)
+            previous_warning_count = self.get_warning_count_from_output(compilation_result=previous_compilation_result)
 
         # Add global data for sketch to report
         sketch_report = {
             self.ReportKeys.name: str(path_relative_to_workspace(path=compilation_result.sketch)),
             self.ReportKeys.compilation_success: compilation_result.success,
             self.ReportKeys.sizes: self.get_sizes_report(current_sizes=current_sizes,
-                                                         previous_sizes=previous_sizes)
+                                                         previous_sizes=previous_sizes),
+            self.ReportKeys.warnings: self.get_warnings_report(current_warnings=current_warning_count,
+                                                               previous_warnings=previous_warning_count)
         }
 
         return sketch_report
@@ -1008,18 +1017,37 @@ def get_size_data_from_output(self, compilation_output, memory_type, size_data_t
 
         return size_data
 
-    def do_deltas_report(self, compilation_result, current_sizes):
+    def get_warning_count_from_output(self, compilation_result):
+        """Parse the stdout from the compilation process and return the number of compiler warnings. Since the
+        information is likely not relevant in that case, "N/A" is returned if compilation failed.
+
+        Keyword arguments:
+        compilation_result -- object returned by compile_sketch()
+        """
+        if compilation_result.success is True:
+            compiler_warning_regex = ":[0-9]+:[0-9]+: warning:"
+            warning_count = len(re.findall(pattern=compiler_warning_regex, string=compilation_result.output))
+        else:
+            warning_count = self.not_applicable_indicator
+
+        return warning_count
+
+    def do_deltas_report(self, compilation_result, current_sizes, current_warnings):
         """Return whether size deltas reporting is enabled.
 
         Keyword arguments:
         compilation_result -- object returned by compile_sketch()
         current_sizes -- memory usage data from the compilation
+        current_warnings -- compiler warning count
         """
         return (
             self.enable_deltas_report
             and compilation_result.success
-            and any(size.get(self.ReportKeys.absolute) != self.not_applicable_indicator for
+            and (
+                any(size.get(self.ReportKeys.absolute) != self.not_applicable_indicator for
                     size in current_sizes)
+                or current_warnings != self.not_applicable_indicator
+            )
         )
 
     def checkout_deltas_base_ref(self):
@@ -1112,6 +1140,42 @@ def get_size_report(self, current_size, previous_size):
 
         return size_report
 
+    def get_warnings_report(self, current_warnings, previous_warnings):
+        """Return a dictionary containing the compiler warning counts.
+
+        Keyword arguments:
+        current_warnings -- compiler warning count at the head ref
+        previous_warnings -- compiler warning count at the base ref, or None if the size deltas feature is not enabled
+        """
+        warnings_report = {
+            self.ReportKeys.current: {
+                self.ReportKeys.absolute: current_warnings,
+            }
+        }
+
+        if previous_warnings is not None:
+            # Deltas reports are enabled
+            # Calculate the change in the warnings count
+            if (
+                current_warnings == self.not_applicable_indicator
+                or previous_warnings == self.not_applicable_indicator
+            ):
+                warnings_delta = self.not_applicable_indicator
+            else:
+                warnings_delta = current_warnings - previous_warnings
+
+            # Print the warning count change to the log
+            print("Change in compiler warning count:", warnings_delta)
+
+            warnings_report[self.ReportKeys.previous] = {
+                self.ReportKeys.absolute: previous_warnings
+            }
+            warnings_report[self.ReportKeys.delta] = {
+                self.ReportKeys.absolute: warnings_delta
+            }
+
+        return warnings_report
+
     def get_sketches_report(self, sketch_report_list):
         """Return the dictionary containing data on all sketch compilations for each board
 
@@ -1141,6 +1205,10 @@ def get_sketches_report(self, sketch_report_list):
         if sizes_summary_report:
             sketches_report[self.ReportKeys.boards][0][self.ReportKeys.sizes] = sizes_summary_report
 
+        warnings_summary_report = self.get_warnings_summary_report(sketch_report_list=sketch_report_list)
+        if warnings_summary_report:
+            sketches_report[self.ReportKeys.boards][0][self.ReportKeys.warnings] = warnings_summary_report
+
         return sketches_report
 
     def get_sizes_summary_report(self, sketch_report_list):
@@ -1241,6 +1309,48 @@ def get_sizes_summary_report(self, sketch_report_list):
 
         return sizes_summary_report
 
+    def get_warnings_summary_report(self, sketch_report_list):
+        """Return a dictionary containing a summary of the compilation warnings count for all sketch compilations.
+
+        Keyword arguments:
+        sketch_report_list -- list of reports from each sketch compilation
+        """
+        summary_report_minimum = None
+        summary_report_maximum = None
+        for sketch_report in sketch_report_list:
+            if self.ReportKeys.delta in sketch_report[self.ReportKeys.warnings]:
+                sketch_report_delta = (
+                    sketch_report[self.ReportKeys.warnings][self.ReportKeys.delta][self.ReportKeys.absolute]
+                )
+
+                if (
+                    summary_report_minimum is None
+                    or summary_report_minimum == self.not_applicable_indicator
+                    or summary_report_minimum > sketch_report_delta
+                ):
+                    summary_report_minimum = sketch_report_delta
+
+                if (
+                    summary_report_maximum is None
+                    or summary_report_maximum == self.not_applicable_indicator
+                    or summary_report_maximum < sketch_report_delta
+                ):
+                    summary_report_maximum = sketch_report_delta
+
+        if summary_report_minimum is not None:
+            warnings_summary_report = {
+                self.ReportKeys.delta: {
+                    self.ReportKeys.absolute: {
+                        self.ReportKeys.minimum: summary_report_minimum,
+                        self.ReportKeys.maximum: summary_report_maximum
+                    }
+                }
+            }
+        else:
+            warnings_summary_report = {}
+
+        return warnings_summary_report
+
     def create_sketches_report_file(self, sketches_report):
         """Write the report for the report sketch to a file.