better debugging

Author: rickeylev

python/private/py_executable.bzl

@@ -557,25 +557,14 @@ def _create_venv(ctx, output_prefix, imports, runtime_details):
     site_init = ctx.actions.declare_file("{}/_bazel_site_init.py".format(site_packages))
     computed_subs = ctx.actions.template_dict()
     computed_subs.add_joined("%imports%", imports, join_with = ":", map_each = _map_each_identity)
-
-    if (ctx.configuration.coverage_enabled and
-        runtime and
-        runtime.coverage_tool):
-        coverage_tool_runfiles_path = "{}/{}".format(
-            ctx.workspace_name,
-            runtime.coverage_tool.short_path,
-        )
-    else:
-        coverage_tool_runfiles_path = ""
-
     ctx.actions.expand_template(
         template = runtime.site_init_template,
         output = site_init,
         substitutions = {
+            "%coverage_tool%": _get_coverage_tool_runfiles_path(ctx, runtime),
             "%import_all%": "True" if ctx.fragments.bazel_py.python_import_all_repositories else "False",
             "%site_init_runfiles_path%": "{}/{}".format(ctx.workspace_name, site_init.short_path),
             "%workspace_name%": ctx.workspace_name,
-            "%coverage_tool%": coverage_tool_runfiles_path,
         },
         computed_substitutions = computed_subs,
     )
@@ -590,6 +579,17 @@ def _create_venv(ctx, output_prefix, imports, runtime_details):
 def _map_each_identity(v):
     return v
 
+def _get_coverage_tool_runfiles_path(ctx, runtime):
+    if (ctx.configuration.coverage_enabled and
+        runtime and
+        runtime.coverage_tool):
+        return "{}/{}".format(
+            ctx.workspace_name,
+            runtime.coverage_tool.short_path,
+        )
+    else:
+        return ""
+
 def _create_stage2_bootstrap(
         ctx,
         *,
@@ -605,23 +605,14 @@ def _create_stage2_bootstrap(
         sibling = output_sibling,
     )
     runtime = runtime_details.effective_runtime
-    if (ctx.configuration.coverage_enabled and
-        runtime and
-        runtime.coverage_tool):
-        coverage_tool_runfiles_path = "{}/{}".format(
-            ctx.workspace_name,
-            runtime.coverage_tool.short_path,
-        )
-    else:
-        coverage_tool_runfiles_path = ""
 
     template = runtime.stage2_bootstrap_template
 
     ctx.actions.expand_template(
         template = template,
         output = output,
         substitutions = {
-            "%coverage_tool%": coverage_tool_runfiles_path,
+            "%coverage_tool%": _get_coverage_tool_runfiles_path(ctx, runtime),
             "%import_all%": "True" if ctx.fragments.bazel_py.python_import_all_repositories else "False",
             "%imports%": ":".join(imports.to_list()),
             "%main%": "{}/{}".format(ctx.workspace_name, main_py.short_path),

python/private/site_init_template.py

@@ -163,7 +163,7 @@ def _maybe_add_path(path):
         if cov_tool:
             _print_verbose_coverage(f"Using toolchain coverage_tool {cov_tool}")
         elif cov_tool := os.environ.get("PYTHON_COVERAGE"):
-            _print_verbose_coverage(f"PYTHON_COVERAGE: {cov_tool}")
+            _print_verbose_coverage(f"Using env var coverage: PYTHON_COVERAGE={cov_tool}")
 
         if cov_tool:
             if os.path.isabs(cov_tool):
@@ -185,7 +185,7 @@ def _maybe_add_path(path):
             coverage_setup = True
         else:
             _print_verbose_coverage(
-                "Coverage was enabled, but python coverage tool was not configured. "
+                "Coverage was enabled, but the coverage tool was not found or valid. "
                 + "To enable coverage, consult the docs at "
                 + "https://rules-python.readthedocs.io/en/latest/coverage.html"
             )
@@ -194,3 +194,4 @@ def _maybe_add_path(path):
 
 
 COVERAGE_SETUP = _setup_sys_path()
+_print_verbose("DONE")

python/private/stage2_bootstrap_template.py

@@ -107,7 +107,7 @@ def print_verbose(*args, mapping=None, values=None):
 def print_verbose_coverage(*args):
     """Print output if VERBOSE_COVERAGE is non-empty in the environment."""
     if is_verbose_coverage():
-        print("bootstrap: coverage:", *args, file=sys.stderr, flush=True)
+        print("bootstrap: stage 2: coverage:", *args, file=sys.stderr, flush=True)
 
 
 def is_verbose_coverage():
@@ -271,6 +271,7 @@ def _run_py(main_filename, *, args, cwd=None):
 
 @contextlib.contextmanager
 def _maybe_collect_coverage(enable):
+    print_verbose_coverage("enabled:", enable)
     if not enable:
         yield
         return
@@ -283,7 +284,9 @@ def _maybe_collect_coverage(enable):
     unique_id = uuid.uuid4()
 
     # We need for coveragepy to use relative paths.  This can only be configured
+    # using an rc file.
     rcfile_name = os.path.join(coverage_dir, ".coveragerc_{}".format(unique_id))
+    print_verbose_coverage("coveragerc file:", rcfile_name)
     with open(rcfile_name, "w") as rcfile:
         rcfile.write(
             """[run]
@@ -318,6 +321,7 @@ def _maybe_collect_coverage(enable):
         finally:
             cov.stop()
             lcov_path = os.path.join(coverage_dir, "pylcov.dat")
+            print_verbose_coverage("generating lcov from:", lcov_path)
             cov.lcov_report(
                 outfile=lcov_path,
                 # Ignore errors because sometimes instrumented files aren't
@@ -398,8 +402,6 @@ def main():
     else:
         coverage_enabled = False
 
-    print_verbose_coverage("coverage_enabled:", coverage_enabled)
-
     with _maybe_collect_coverage(enable=coverage_enabled):
         # The first arg is this bootstrap, so drop that for the re-invocation.
         _run_py(main_filename, args=sys.argv[1:])