Debug-time environment variables can be set with set_env.py

7 files changed, 103 insertions, 1 deletions

diff --git a/coverage/data.py b/coverage/data.py
index 4a996e68..d6061293 100644
--- a/coverage/data.py
+++ b/coverage/data.py
@@ -640,6 +640,7 @@ class CoverageJsonData(object):
         return self._arcs is not None
 
 
+# $set_env.py: COVERAGE_STORAGE - The storage implementation to use: sql (default), or json.
 STORAGE = os.environ.get("COVERAGE_STORAGE", "sql")
 if STORAGE == "json":
     CoverageData = CoverageJsonData
diff --git a/coverage/misc.py b/coverage/misc.py
index 1782d285..c484d61e 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -49,6 +49,7 @@ def dummy_decorator_with_args(*args_unused, **kwargs_unused):
 
 # Environment COVERAGE_NO_CONTRACTS=1 can turn off contracts while debugging
 # tests to remove noise from stack traces.
+# $set_env.py: COVERAGE_NO_CONTRACTS - Disable PyContracts to simplify stack traces.
 USE_CONTRACTS = env.TESTING and not bool(int(os.environ.get("COVERAGE_NO_CONTRACTS", 0)))
 
 # Use PyContracts for assertion testing on parameters and returns, but only if
diff --git a/coverage/parser.py b/coverage/parser.py
index 6faa36e2..6ae81c19 100644
--- a/coverage/parser.py
+++ b/coverage/parser.py
@@ -491,6 +491,7 @@ new_contract('ArcStarts', lambda seq: all(isinstance(x, ArcStart) for x in seq))
 
 
 # Turn on AST dumps with an environment variable.
+# $set_env.py: COVERAGE_AST_DUMP - Dump the AST nodes when parsing code.
 AST_DUMP = bool(int(os.environ.get("COVERAGE_AST_DUMP", 0)))
 
 class NodeList(object):
@@ -535,6 +536,7 @@ class AstArcAnalyzer(object):
         self.missing_arc_fragments = collections.defaultdict(list)
         self.block_stack = []
 
+        # $set_env.py: COVERAGE_TRACK_ARCS - Trace every arc added while parsing code.
         self.debug = bool(int(os.environ.get("COVERAGE_TRACK_ARCS", 0)))
 
     def analyze(self):
diff --git a/doc/contributing.rst b/doc/contributing.rst
index 90d73097..319a9d5c 100644
--- a/doc/contributing.rst
+++ b/doc/contributing.rst
@@ -137,7 +137,7 @@ these as 1 to use them:
 - COVERAGE_NO_CTRACER disables the C tracer if you only want to run the
   PyTracer tests.
 
-- COVEGE_AST_DUMP will dump the AST tree as it is being used during code
+- COVERAGE_AST_DUMP will dump the AST tree as it is being used during code
   parsing.
 
 - COVERAGE_KEEP_TMP keeps the temporary directories in which tests are run.
diff --git a/igor.py b/igor.py
index 750ea688..78de37a2 100644
--- a/igor.py
+++ b/igor.py
@@ -74,8 +74,10 @@ def label_for_tracer(tracer):
 def should_skip(tracer):
     """Is there a reason to skip these tests?"""
     if tracer == "py":
+        # $set_env.py: COVERAGE_NO_PYTRACER - Don't run the tests under the Python tracer.
         skipper = os.environ.get("COVERAGE_NO_PYTRACER")
     else:
+        # $set_env.py: COVERAGE_NO_CTRACER - Don't run the tests under the C tracer.
         skipper = os.environ.get("COVERAGE_NO_CTRACER")
 
     if skipper:
diff --git a/lab/set_env.py b/lab/set_env.py
new file mode 100755
index 00000000..184649ee
--- /dev/null
+++ b/lab/set_env.py
@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+#
+# Run this like:
+#
+#   $ $(lab/set_env.py)
+#
+
+import functools
+import glob
+import itertools
+import os
+import re
+import sys
+
+pstderr = functools.partial(print, file=sys.stderr)
+
+SETTINGS = []
+
+line_pattern = r"\$set_env.py: (\w+) - (.*)"
+globs = "*/*.py *.py"
+
+filenames = itertools.chain.from_iterable(glob.glob(g) for g in globs.split())
+files = 0
+for filename in filenames:
+    files += 1
+    with open(filename) as f:
+        for line in f:
+            m = re.search(line_pattern, line)
+            if m:
+                SETTINGS.append(m.groups())
+pstderr("Read {} files".format(files))
+
+
+def read_them():
+    values = {}
+    for name, _ in SETTINGS:
+        values[name] = os.environ.get(name)
+    return values
+
+def show_them(values):
+    for i, (name, description) in enumerate(SETTINGS, start=1):
+        value = values[name]
+        if value is None:
+            eq = ' '
+            value = ''
+        else:
+            eq = '='
+            value = repr(value)
+        pstderr("{:2d}: {:>30s} {} {:12s}   {}".format(i, name, eq, value, description))
+
+def set_by_num(values, n, value):
+    setting_name = SETTINGS[int(n)-1][0]
+    values[setting_name] = value
+
+def get_new_values(values):
+    show = True
+    while True:
+        if show:
+            show_them(values)
+            show = False
+            pstderr("")
+        pstderr("> ", end='')
+        sys.stderr.flush()
+        try:
+            cmd = input("").strip().split(None, 1)
+        except EOFError:
+            pstderr("\n")
+            break
+        if not cmd:
+            continue
+        if cmd[0] == 'q':
+            break
+        if cmd[0] == 'x':
+            set_by_num(values, cmd[1], None)
+        else:
+            try:
+                nsetting = int(cmd[0])
+            except ValueError:
+                pass
+            else:
+                set_by_num(values, nsetting, cmd[1])
+        show = True
+
+    return values
+
+def as_exports(values):
+    exports = []
+    for name, value in values.items():
+        if value is None:
+            exports.append("export -n {}".format(name))
+        else:
+            exports.append("export {}={!r}".format(name, value))
+    return "eval " + "; ".join(exports)
+
+print(as_exports(get_new_values(read_them())))
diff --git a/tests/coveragetest.py b/tests/coveragetest.py
index 08edd62f..d08c334e 100644
--- a/tests/coveragetest.py
+++ b/tests/coveragetest.py
@@ -84,6 +84,7 @@ class CoverageTest(
     temp_dir_prefix = "coverage_test/"
 
     # Keep the temp directories if the env says to.
+    # $set_env.py: COVERAGE_KEEP_TMP - Keep the temp directories made by tests.
     keep_temp_dir = bool(int(os.getenv("COVERAGE_KEEP_TMP", 0)))
 
     def setUp(self):