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Option to output format? #587

nedbat opened this issue Jun 16, 2017 · 32 comments

Option to output format? #587

nedbat opened this issue Jun 16, 2017 · 32 comments
enhancement New feature or request


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nedbat commented Jun 16, 2017

Originally reported by Matthew Crenshaw (Bitbucket: sgtsquiggs, GitHub: sgtsquiggs)

So that we can use with IDE plugins that read the standard format and highlight covered/uncovered lines. Would be super great!

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nedbat commented Jun 16, 2017

Interesting idea. Do you have a link to information about the file format?

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nedbat commented Jun 16, 2017

Original comment by Matthew Crenshaw (Bitbucket: sgtsquiggs, GitHub: sgtsquiggs)

lcov format

   Following  is  a  quick  description of the tracefile format as used by
   genhtml, geninfo and lcov.

   A tracefile is made up of several human-readable lines of text, divided
   into sections. If available, a tracefile begins with the testname which
   is stored in the following format:

     TN:<test name>

   For each source file referenced in the .da file,  there  is  a  section
   containing filename and coverage data:

     SF:<absolute path to the source file>

   Following is a list of line numbers for each function name found in the
   source file:

     FN:<line number of function start>,<function name>

   Next, there is a list of execution counts for each  instrumented  func‐

     FNDA:<execution count>,<function name>

   This  list  is followed by two lines containing the number of functions
   found and hit:

     FNF:<number of functions found>
     FNH:<number of function hit>

   Branch coverage information is stored which one line per branch:

     BRDA:<line number>,<block number>,<branch number>,<taken>

   Block number and branch number are gcc internal  IDs  for  the  branch.
   Taken  is either '-' if the basic block containing the branch was never
   executed or a number indicating how often that branch was taken.

   Branch coverage summaries are stored in two lines:

     BRF:<number of branches found>
     BRH:<number of branches hit>

   Then there is a list of execution counts  for  each  instrumented  line
   (i.e. a line which resulted in executable code):

     DA:<line number>,<execution count>[,<checksum>]

   Note  that  there  may be an optional checksum present for each instru‐
   mented line. The current geninfo implementation uses  an  MD5  hash  as
   checksumming algorithm.

   At  the  end of a section, there is a summary about how many lines were
   found and how many were actually instrumented:

     LH:<number of lines with a non-zero execution count>
     LF:<number of instrumented lines>

   Each sections ends with:


   In addition to the main source code file there  are  sections  for  all
   #included files which also contain executable code.

   Note that the absolute path of a source file is generated by interpret‐
   ing the contents of the respective .bb file  (see  gcov  (1)  for  more
   information  on  this  file type). Relative filenames are prefixed with
   the directory in which the .bb file is found.

   Note also that symbolic links to the .bb file will be resolved so  that
   the  actual  file  path  is  used  instead  of the path to a link. This
   approach is necessary for the mechanism to  work  with  the  /proc/gcov

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nedbat commented Jun 16, 2017

I'm a bit nervous about the language semantics assumed by this file format (list of functions found?), but that seems to be par for the course for any of these formats.

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nedbat commented Mar 15, 2018

Original comment by Bojan Kogoj (Bitbucket: bojankogoj, GitHub: bojankogoj)

Any progress? I'd like to use vs code coverage plugin but it doesn't support current format

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nedbat commented Mar 15, 2018

I am not working on this at the moment, and probably will not be implementing this any time soon. There's no reason this has to be built-in to You can get data from coverage in XML format, or using the data API, and create a file like this with separate code.

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gpshead commented Oct 28, 2019

FWIW we've been using a patch for eons at work that has coverage generate LCOV files. Let me see about extricating that and making a PR.

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gpshead commented Oct 29, 2019

Example non-great code posted as a PR to help kick things off. :)

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ulfjack commented Dec 17, 2019

We've gotten repeated requests to support python coverage in Bazel ( and integrating it in a multi-language situation (e.g., coverage for Python + C++) requires being able to generate lcov format.

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gpshead commented Dec 17, 2019

I really haven't spend much time untangling this, are there any links to the specifics of the LCOV format or the specifics of what subset of that Bazel expects from LCOV files? (see also the comment thread on (#863).

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ulfjack commented Dec 19, 2019

Bazel supports multi-language coverage, e.g., getting coverage results from Java, Python, and C++ from a single test run. However, in order to generate a combined report, all of these need to be converted into a single unified format. We've looked at different formats, and it seems like every coverage tool / implementation comes with its own format, and none is particularly prevalent. Our main restriction is that it shouldn't be too verbose (so XML might be a problem). Whatever format we standardize on in Bazel, we need to convert from all other formats to that one.

Right now, we're using lcov as our "standard" format, which is fairly simple, reasonably compact, and it's the same format Google uses internally (full disclosure: I work for Google). For large code bases, we're seeing multi-GB lcov outputs, so less compact could be problematic.

Ideally, whatever format we use also supports advanced features like branch coverage or edge coverage, but it's more important to settle on something than to have the latest and greatest features.

Each tool has to decide what lines to mark as covered. I would strongly recommend that it at least correctly annotate on a per-file level; there are potential uses for automatically selecting affected tests based on coverage information from a previous test run to reduce CI resource usage.

One more thing: Python is an exception, but we otherwise don't allow access to source code from the test run. Bazel sandboxes execution, and - by design - does not support general source access. We collect lcov from the test runs, and then generate an HTML report as a post-process during which we allow source access. As a corollary, the coverage tool should not put absolute paths into the output, because the sandbox is in a different file system location. We can post-process the data if necessary, but it's not ideal. Ideal is to use relative paths to the current working directory.

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Hope to see this being implemented soon!

If anyone needs a converting tool in the meantime, I created a simple converter here:

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Hi @nedbat, we are currently looking at implementing code coverage for python in bazel. What do you think of a feature for, that would act similarly to and, and output a file in LCOV format? Do you have thoughts on what such an implementation should look like?

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nedbat commented Nov 30, 2021

@bradb423 I know nothing about the LCOV format, but the code in @chaychoong's repo looks pretty simple. Perhaps adapting that to a new command in is the way to go? What other guidance would you need?

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nedbat commented Nov 30, 2021

I should say: I'm torn between adding features like this to (to keep things convenient and findable), and leaving them as separate addons that use supported APIs in instead (to keep light, and to foster innovation). Thoughts?

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I should say: I'm torn between adding features like this to (to keep things convenient and findable), and leaving them as separate addons that use supported APIs in instead (to keep light, and to foster innovation). Thoughts?

From what I've seen lcov seems to be a standard (non human readable) format that I've encountered across a few different projects/tech stacks. Specifically handy for me when combined with github actions to produce a simple coverage report on things like pull requests. I'd vote it should be core, but that just may be my bias/exposure to it. (And having to fork @chaychoong 's repo to support python < 3.8, lol).

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TLATER commented Nov 30, 2021

Istanbul's support list might be interesting to look at, since it has both a variety of output formats and supports using arbitrary npm packages as output plugins. I couldn't find any public plugins that provide formats not natively supported by Istanbul, so that list is probably fairly exhaustive as far as non-language-specific formats go.

The computer-readable formats listed there are:

  • Clover
  • Cobertura (a variant of which I believe currently outputs as "XML"?)
  • JSON (which I believe to be bespoke)
  • lcov

grcov is also interesting to me because it's Rust and I like Rust ;)

  • lcov
  • Cobertura
  • Covdir (Another JSON output that seems semi-bespoke)

These oddities also crop up there:

  • Coveralls ('s specific format, but they support lcov and others too so I don't really see why, probably more language-specific data?)
  • ADE (AWS specific?)

I've had a skim through various other projects too, most other formats are specific to the coverage tool (e.g. Java's Jacoco, Ruby's SimpleCov), and consumers just implement parsing for their formats. Bazel actually implements its own formatter for Jacoco to get it to be lcov ;)

I think my personal opinion is that there simply aren't enough "generic" variants of these formats to warrant the overhead of a plugin system at the moment (Istanbul certainly doesn't seem to need it), but I recognize I'm a downstream user, mostly want convenience and share @TheCleric 's bias.

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I think it's relevant to this discussion to also point to Gcovr - on the one hand it's written in Python and offers a nice set of features and customizability, on the other hand it generates nice coverage reports from gcc's gcov data (not lcov).

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nedbat commented Dec 1, 2021

I'm not sure where this conversation is going! :)

About LCOV: are there variants that would need to be supported, or is it well standardized? It does seem like a widely used format that could be supported in the core tool.

About plugins: there is definitely no need to write plugins for reporting. Reporting can happen in a separate tool after the fact if need be for unusual formats.

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About LCOV: are there variants that would need to be supported, or is it well standardized? It does seem like a widely used format that could be supported in the core tool.

To my knowledge it's standardized. For example using my forked version of @chaychoong 's repo to out lcov data, I had no issues hooking it up to my lcov CI pipeline that also consumes lcov output from other sources such as Jest on a node app.

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bradb423 commented Dec 8, 2021

We currently have a pull request open to provide some LCOV support. Currently this does not have branch coverage, but this feature is being worked on.

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We currently have a pull request open to provide some LCOV support. Currently this does not have branch coverage, but this feature is being worked on.

@bradb423 Given that it's of a compatible license, would it make sense to just merge what @chaychoong has done as it does have branch coverage?

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TLATER commented Dec 8, 2021

would it make sense to just merge what @chaychoong has done as it does have branch coverage?

@TheCleric @chaychoong 's implementation does not do branch coverage either:

Branches being marked correctly in the genhtml output is incidental of the line coverage, but this is different from the BRDA/BRF/BRH records documented here.

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would it make sense to just merge what @chaychoong has done as it does have branch coverage?

@TheCleric @chaychoong 's implementation does not do branch coverage either:

Branches being marked correctly in the genhtml output is incidental of the line coverage, but this is different from the BRDA/BRF/BRH records documented here.

Ahh, good to know. Thanks!

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TLATER commented Dec 8, 2021

That's not to say it might not be worth merging without fully implemented branch coverage :) lcov is quite flexible, a file with no branch/function records is valid. Most of what other tools use is in the line coverage records anyway.

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nedbat commented Dec 8, 2021

I really appreciate all the interest in this. I am still wondering about keeping this as a separate project instead of adding a command to

@nedbat nedbat added the next label Dec 9, 2021
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TLATER commented Dec 14, 2021

I really appreciate all the interest in this. I am still wondering about keeping this as a separate project instead of adding a command to

I think we all know that adding more public API is always scary, it's hard to go back on in the future without breaking stuff for people - and there are already a handful of us who intend to build infrastructure on this.

On the other hand, I've looked through @bradb423 's patch, and the implementation doesn't seem too invasive. It uses internal API that already exists for the other reporters, so I think maintenance should be fairly minimal. lcov is also slow-moving (hasn't changed in over a decade, last commit to the format doc is from 12 years ago), and one of the simpler formats, so I don't think there's a major cost to having that command around either.

Ultimately this is the maintainers' dilemma, and I don't think we can help much with the decision, besides saying pretty please :) If you have particular concerns about the lcov format I think I'm reasonably versed on it at this point (much better than two weeks ago anyway)?

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nedbat commented Dec 14, 2021

@TLATER thanks. One (small) concern is the use of md5. I know it isn't a security concern the way it's used here, but there are dumb security scanners out there that flag things like that. Do we need the md5 fingerprints in the data file? What happens if we leave them out?

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TLATER commented Dec 14, 2021

@nedbat That checksum is only used to assert that any later analysis is actually running on the correct lines (and say, nobody has updated them in the mean time). If it's left out, tools just don't check the lines. It's nice for more complex use cases, but not essential.

The checksum is documented as not demanding a specific implementation, so we could use sha256 or such instead. I've not tried doing that before, so no idea what issues that will tickle out, I just know upstream uses md5.

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TLATER commented Dec 14, 2021

Hmm, yeah, looks like upstream doesn't actually support anything besides md5, despite that claim in the docs:

If the dumb scanners are a concern, I'd not be terribly sad to lose the checksum :)

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nedbat commented Jan 22, 2022

@bradb423's lcov implementation is merged as of 2e8c191.

@nedbat nedbat closed this as completed Jan 22, 2022
@nedbat nedbat removed the next label Jan 22, 2022
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lazka commented Jan 23, 2022

Thanks @bradb423 @nedbat 🙏

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nedbat commented Jan 25, 2022

This is now released as part of coverage 6.3.

netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this issue Aug 24, 2022
Version 6.4.4 — 2022-08-16

- Wheels are now provided for Python 3.11.

.. _changes_6-4-3:

Version 6.4.3 — 2022-08-06

- Fix a failure when combining data files if the file names contained
  glob-like patterns (`pull 1405`_).  Thanks, Michael Krebs and Benjamin

- Fix a messaging failure when combining Windows data files on a different
  drive than the current directory. (`pull 1430`_, fixing `issue 1428`_).
  Thanks, Lorenzo Micò.

- Fix path calculations when running in the root directory, as you might do in
  a Docker container: `pull 1403`_, thanks Arthur Rio.

- Filtering in the HTML report wouldn't work when reloading the index page.
  This is now fixed (`pull 1413`_).  Thanks, Marc Legendre.

- Fix a problem with Cython code measurement (`pull 1347`_, fixing `issue
  972`_).  Thanks, Matus Valo.

.. _issue 972: nedbat/coveragepy#972
.. _pull 1347: nedbat/coveragepy#1347
.. _pull 1403: nedbat/coveragepy#1403
.. _pull 1405: nedbat/coveragepy#1405
.. _pull 1413: nedbat/coveragepy#1413
.. _issue 1428: nedbat/coveragepy#1428
.. _pull 1430: nedbat/coveragepy#1430

.. _changes_6-4-2:

Version 6.4.2 — 2022-07-12

- Updated for a small change in Python 3.11.0 beta 4: modules now start with a
  line with line number 0, which is ignored.  This line cannnot be executed, so
  coverage totals were thrown off.  This line is now ignored by,
  but this also means that truly empty modules (like ````) have no
  lines in them, rather than one phantom line.  Fixes `issue 1419`_.

- Internal debugging data added to sys.modules is now an actual module, to
  avoid confusing code that examines everything in sys.modules.  Thanks,
  Yilei Yang (`pull 1399`_).

.. _pull 1399: nedbat/coveragepy#1399
.. _issue 1419: nedbat/coveragepy#1419

.. _changes_6-4-1:

Version 6.4.1 — 2022-06-02

- Greatly improved performance on PyPy, and other environments that need the
  pure Python trace function.  Thanks, Carl Friedrich Bolz-Tereick (`pull
  1381`_ and `pull 1388`_).  Slightly improved performance when using the C
  trace function, as most environments do.  Closes `issue 1339`_.

- The conditions for using tomllib from the standard library have been made
  more precise, so that 3.11 alphas will continue to work. Closes `issue

.. _issue 1339: nedbat/coveragepy#1339
.. _pull 1381: nedbat/coveragepy#1381
.. _pull 1388: nedbat/coveragepy#1388
.. _issue 1390: nedbat/coveragepy#1390

.. _changes_64:

Version 6.4 — 2022-05-22

- A new setting, :ref:`config_run_sigterm`, controls whether a SIGTERM signal
  handler is used.  In 6.3, the signal handler was always installed, to capture
  data at unusual process ends.  Unfortunately, this introduced other problems
  (see `issue 1310`_).  Now the signal handler is only used if you opt-in by
  setting ``[run] sigterm = true``.

- Small changes to the HTML report:

  - Added links to next and previous file, and more keyboard shortcuts: ``[``
    and ``]`` for next file and previous file; ``u`` for up to the index; and
    ``?`` to open/close the help panel.  Thanks, `J. M. F. Tsang
    <pull 1364_>`_.

  - The timestamp and version are displayed at the top of the report.  Thanks,
    `Ammar Askar <pull 1354_>`_. Closes `issue 1351`_.

- A new debug option ``debug=sqldata`` adds more detail to ``debug=sql``,
  logging all the data being written to the database.

- Previously, running ``coverage report`` (or any of the reporting commands) in
  an empty directory would create a .coverage data file.  Now they do not,
  fixing `issue 1328`_.

- On Python 3.11, the ``[toml]`` extra no longer installs tomli, instead using
  tomllib from the standard library.  Thanks `Shantanu <pull 1359_>`_.

- In-memory CoverageData objects now properly update(), closing `issue 1323`_.

.. _issue 1310: nedbat/coveragepy#1310
.. _issue 1323: nedbat/coveragepy#1323
.. _issue 1328: nedbat/coveragepy#1328
.. _issue 1351: nedbat/coveragepy#1351
.. _pull 1354: nedbat/coveragepy#1354
.. _pull 1359: nedbat/coveragepy#1359
.. _pull 1364: nedbat/coveragepy#1364

.. _changes_633:

Version 6.3.3 — 2022-05-12

- Fix: now builds successfully on CPython 3.11 (3.11.0b1) again.
  Closes `issue 1367`_.  Some results for generators may have changed.

.. _issue 1367: nedbat/coveragepy#1367

.. _changes_632:

Version 6.3.2 — 2022-02-20

- Fix: adapt to pypy3.9's decorator tracing behavior.  It now traces function
  decorators like CPython 3.8: both the @-line and the def-line are traced.
  Fixes `issue 1326`_.

- Debug: added ``pybehave`` to the list of :ref:`coverage debug <cmd_debug>`
  and :ref:`cmd_run_debug` options.

- Fix: show an intelligible error message if ``--concurrency=multiprocessing``
  is used without a configuration file.  Closes `issue 1320`_.

.. _issue 1320: nedbat/coveragepy#1320
.. _issue 1326: nedbat/coveragepy#1326

.. _changes_631:

Version 6.3.1 — 2022-02-01

- Fix: deadlocks could occur when terminating processes.  Some of these
  deadlocks (described in `issue 1310`_) are now fixed.

- Fix: a signal handler was being set from multiple threads, causing an error:
  "ValueError: signal only works in main thread".  This is now fixed, closing
  `issue 1312`_.

- Fix: ``--precision`` on the command-line was being ignored while considering
  ``--fail-under``.  This is now fixed, thanks to
  `Marcelo Trylesinski <pull 1317_>`_.

- Fix: releases no longer provide 3.11.0-alpha wheels. uses CPython
  internal fields which are moving during the alpha phase. Fixes `issue 1316`_.

.. _issue 1310: nedbat/coveragepy#1310
.. _issue 1312: nedbat/coveragepy#1312
.. _issue 1316: nedbat/coveragepy#1316
.. _pull 1317: nedbat/coveragepy#1317

.. _changes_63:

Version 6.3 — 2022-01-25

- Feature: Added the ``lcov`` command to generate reports in LCOV format.
  Thanks, `Bradley Burns <pull 1289_>`_. Closes issues `587 <issue 587_>`_
  and `626 <issue 626_>`_.

- Feature: the coverage data file can now be specified on the command line with
  the ``--data-file`` option in any command that reads or writes data.  This is
  in addition to the existing ``COVERAGE_FILE`` environment variable.  Closes
  `issue 624`_. Thanks, `Nikita Bloshchanevich <pull 1304_>`_.

- Feature: coverage measurement data will now be written when a SIGTERM signal
  is received by the process.  This includes
  :meth:`Process.terminate <python:multiprocessing.Process.terminate>`,
  and other ways to terminate a process.  Currently this is only on Linux and
  Mac; Windows is not supported.  Fixes `issue 1307`_.

- Dropped support for Python 3.6, which reached end-of-life on 2021-12-23.

- Updated Python 3.11 support to 3.11.0a4, fixing `issue 1294`_.

- Fix: the coverage data file is now created in a more robust way, to avoid
  problems when multiple processes are trying to write data at once. Fixes
  issues `1303 <issue 1303_>`_ and `883 <issue 883_>`_.

- Fix: a .gitignore file will only be written into the HTML report output
  directory if the directory is empty.  This should prevent certain unfortunate
  accidents of writing the file where it is not wanted.

- Releases now have MacOS arm64 wheels for Apple Silicon, fixing `issue 1288`_.

.. _issue 587: nedbat/coveragepy#587
.. _issue 624: nedbat/coveragepy#624
.. _issue 626: nedbat/coveragepy#626
.. _issue 883: nedbat/coveragepy#883
.. _issue 1288: nedbat/coveragepy#1288
.. _issue 1294: nedbat/coveragepy#1294
.. _issue 1303: nedbat/coveragepy#1303
.. _issue 1307: nedbat/coveragepy#1307
.. _pull 1289: nedbat/coveragepy#1289
.. _pull 1304: nedbat/coveragepy#1304

.. _changes_62:

Version 6.2 — 2021-11-26

- Feature: Now the ``--concurrency`` setting can now have a list of values, so
  that threads and another lightweight threading package can be measured
  together, such as ``--concurrency=gevent,thread``.  Closes `issue 1012`_ and
  `issue 1082`_.

- Fix: A module specified as the ``source`` setting is imported during startup,
  before the user program imports it.  This could cause problems if the rest of
  the program isn't ready yet.  For example, `issue 1203`_ describes a Django
  setting that is accessed before settings have been configured.  Now the early
  import is wrapped in a try/except so errors then don't stop execution.

- Fix: A colon in a decorator expression would cause an exclusion to end too
  early, preventing the exclusion of the decorated function. This is now fixed.

- Fix: The HTML report now will not overwrite a .gitignore file that already
  exists in the HTML output directory (follow-on for `issue 1244`_).

- API: The exceptions raised by have been specialized, to provide
  finer-grained catching of exceptions by third-party code.

- API: Using ``suffix=False`` when constructing a Coverage object with
  multiprocessing wouldn't suppress the data file suffix (`issue 989`_).  This
  is now fixed.

- Debug: The ``coverage debug data`` command will now sniff out combinable data
  files, and report on all of them.

- Debug: The ``coverage debug`` command used to accept a number of topics at a
  time, and show all of them, though this was never documented.  This no longer
  works, to allow for command-line options in the future.

.. _issue 989: nedbat/coveragepy#989
.. _issue 1012: nedbat/coveragepy#1012
.. _issue 1082: nedbat/coveragepy#1082
.. _issue 1203: nedbat/coveragepy#1203

.. _changes_612:

Version 6.1.2 — 2021-11-10

- Python 3.11 is supported (tested with 3.11.0a2).  One still-open issue has to
  do with `exits through with-statements <issue 1270_>`_.

- Fix: When remapping file paths through the ``[paths]`` setting while
  combining, the ``[run] relative_files`` setting was ignored, resulting in
  absolute paths for remapped file names (`issue 1147`_).  This is now fixed.

- Fix: Complex conditionals over excluded lines could have incorrectly reported
  a missing branch (`issue 1271`_). This is now fixed.

- Fix: More exceptions are now handled when trying to parse source files for
  reporting.  Problems that used to terminate can now be handled
  with ``[report] ignore_errors``.  This helps with plugins failing to read
  files (`django_coverage_plugin issue 78`_).

- Fix: Removed another vestige of jQuery from the source tarball
  (`issue 840`_).

- Fix: Added a default value for a new-to-6.x argument of an internal class.
  This unsupported class is being used by coveralls (`issue 1273`_). Although
  I'd rather not "fix" unsupported interfaces, it's actually nicer with a
  default value.

.. _django_coverage_plugin issue 78: nedbat/django_coverage_plugin#78
.. _issue 1147: nedbat/coveragepy#1147
.. _issue 1270: nedbat/coveragepy#1270
.. _issue 1271: nedbat/coveragepy#1271
.. _issue 1273: nedbat/coveragepy#1273

.. _changes_611:

Version 6.1.1 — 2021-10-31

- Fix: The sticky header on the HTML report didn't work unless you had branch
  coverage enabled. This is now fixed: the sticky header works for everyone.
  (Do people still use coverage without branch measurement!? j/k)

- Fix: When using explicitly declared namespace packages, the "already imported
  a file that will be measured" warning would be issued (`issue 888`_).  This
  is now fixed.

.. _issue 888: nedbat/coveragepy#888

.. _changes_61:

Version 6.1 — 2021-10-30

- Deprecated: The ``annotate`` command and the ``Coverage.annotate`` function
  will be removed in a future version, unless people let me know that they are
  using it.  Instead, the ``html`` command gives better-looking (and more
  accurate) output, and the ``report -m`` command will tell you line numbers of
  missing lines.  Please get in touch if you have a reason to use ``annotate``
  over those better options:

- Feature: Coverage now sets an environment variable, ``COVERAGE_RUN`` when
  running your code with the ``coverage run`` command.  The value is not
  important, and may change in the future.  Closes `issue 553`_.

- Feature: The HTML report pages for Python source files now have a sticky
  header so the file name and controls are always visible.

- Feature: The ``xml`` and ``json`` commands now describe what they wrote

- Feature: The ``html``, ``combine``, ``xml``, and ``json`` commands all accept
  a ``-q/--quiet`` option to suppress the messages they write to stdout about
  what they are doing (`issue 1254`_).

- Feature: The ``html`` command writes a ``.gitignore`` file into the HTML
  output directory, to prevent the report from being committed to git.  If you
  want to commit it, you will need to delete that file.  Closes `issue 1244`_.

- Feature: Added support for PyPy 3.8.

- Fix: More generated code is now excluded from measurement.  Code such as
  `attrs`_ boilerplate, or doctest code, was being measured though the
  synthetic line numbers meant they were never reported.  Once Cython was
  involved though, the generated .so files were parsed as Python, raising
  syntax errors, as reported in `issue 1160`_.  This is now fixed.

- Fix: When sorting human-readable names, numeric components are sorted
  correctly: will appear after  This applies to file names,
  module names, environment variables, and test contexts.

- Performance: Branch coverage measurement is faster, though you might only
  notice on code that is executed many times, such as long-running loops.

- Build: jQuery is no longer used or vendored (`issue 840`_ and `issue 1118`_).
  Huge thanks to Nils Kattenbeck (septatrix) for the conversion to vanilla
  JavaScript in `pull request 1248`_.

.. _issue 553: nedbat/coveragepy#553
.. _issue 840: nedbat/coveragepy#840
.. _issue 1118: nedbat/coveragepy#1118
.. _issue 1160: nedbat/coveragepy#1160
.. _issue 1244: nedbat/coveragepy#1244
.. _pull request 1248: nedbat/coveragepy#1248
.. _issue 1254: nedbat/coveragepy#1254
.. _attrs:

.. _changes_602:

Version 6.0.2 — 2021-10-11

- Namespace packages being measured weren't properly handled by the new code
  that ignores third-party packages. If the namespace package was installed, it
  was ignored as a third-party package.  That problem (`issue 1231`_) is now

- Packages named as "source packages" (with ``source``, or ``source_pkgs``, or
  pytest-cov's ``--cov``) might have been only partially measured.  Their
  top-level statements could be marked as unexecuted, because they were
  imported by before measurement began (`issue 1232`_).  This is
  now fixed, but the package will be imported twice, once by, then
  again by your test suite.  This could cause problems if importing the package
  has side effects.

- The :meth:`.CoverageData.contexts_by_lineno` method was documented to return
  a dict, but was returning a defaultdict.  Now it returns a plain dict.  It
  also no longer returns negative numbered keys.

.. _issue 1231: nedbat/coveragepy#1231
.. _issue 1232: nedbat/coveragepy#1232

.. _changes_601:

Version 6.0.1 — 2021-10-06

- In 6.0, the exceptions moved from coverage.misc to
  coverage.exceptions. These exceptions are not part of the public supported
  API, CoverageException is. But a number of other third-party packages were
  importing the exceptions from coverage.misc, so they are now available from
  there again (`issue 1226`_).

- Changed an internal detail of how tomli is imported, so that tomli can use for their own test suite (`issue 1228`_).

- Defend against an obscure possibility under code obfuscation, where a
  function can have an argument called "self", but no local named "self"
  (`pull request 1210`_).  Thanks, Ben Carlsson.

.. _pull request 1210: nedbat/coveragepy#1210
.. _issue 1226: nedbat/coveragepy#1226
.. _issue 1228: nedbat/coveragepy#1228

.. _changes_60:

Version 6.0 — 2021-10-03

- The ``coverage html`` command now prints a message indicating where the HTML
  report was written.  Fixes `issue 1195`_.

- The ``coverage combine`` command now prints messages indicating each data
  file being combined.  Fixes `issue 1105`_.

- The HTML report now includes a sentence about skipped files due to
  ``skip_covered`` or ``skip_empty`` settings.  Fixes `issue 1163`_.

- Unrecognized options in the configuration file are no longer errors. They are
  now warnings, to ease the use of coverage across versions.  Fixes `issue

- Fix handling of exceptions through context managers in Python 3.10. A missing
  exception is no longer considered a missing branch from the with statement.
  Fixes `issue 1205`_.

- Fix another rarer instance of "Error binding parameter 0 - probably
  unsupported type." (`issue 1010`_).

- Creating a directory for the coverage data file now is safer against
  conflicts when two coverage runs happen simultaneously (`pull 1220`_).
  Thanks, Clément Pit-Claudel.

.. _issue 1035: nedbat/coveragepy#1035
.. _issue 1105: nedbat/coveragepy#1105
.. _issue 1163: nedbat/coveragepy#1163
.. _issue 1195: nedbat/coveragepy#1195
.. _issue 1205: nedbat/coveragepy#1205
.. _pull 1220: nedbat/coveragepy#1220

.. _changes_60b1:

Version 6.0b1 — 2021-07-18

- Dropped support for Python 2.7, PyPy 2, and Python 3.5.

- Added support for the Python 3.10 ``match/case`` syntax.

- Data collection is now thread-safe.  There may have been rare instances of
  exceptions raised in multi-threaded programs.

- Plugins (like the `Django coverage plugin`_) were generating "Already
  imported a file that will be measured" warnings about Django itself.  These
  have been fixed, closing `issue 1150`_.

- Warnings generated by are now real Python warnings.

- Using ``--fail-under=100`` with coverage near 100% could result in the
  self-contradictory message :code:`total of 100 is less than fail-under=100`.
  This bug (`issue 1168`_) is now fixed.

- The ``COVERAGE_DEBUG_FILE`` environment variable now accepts ``stdout`` and
  ``stderr`` to write to those destinations.

- TOML parsing now uses the `tomli`_ library.

- Some minor changes to usually invisible details of the HTML report:

  - Use a modern hash algorithm when fingerprinting, for high-security
    environments (`issue 1189`_).  When generating the HTML report, we save the
    hash of the data, to avoid regenerating an unchanged HTML page. We used to
    use MD5 to generate the hash, and now use SHA-3-256.  This was never a
    security concern, but security scanners would notice the MD5 algorithm and
    raise a false alarm.

  - Change how report file names are generated, to avoid leading underscores
    (`issue 1167`_), to avoid rare file name collisions (`issue 584`_), and to
    avoid file names becoming too long (`issue 580`_).

.. _Django coverage plugin:
.. _issue 580: nedbat/coveragepy#580
.. _issue 584: nedbat/coveragepy#584
.. _issue 1150: nedbat/coveragepy#1150
.. _issue 1167: nedbat/coveragepy#1167
.. _issue 1168: nedbat/coveragepy#1168
.. _issue 1189: nedbat/coveragepy#1189
.. _tomli:

.. _changes_56b1:

Version 5.6b1 — 2021-04-13

Note: 5.6 final was never released. These changes are part of 6.0.

- Third-party packages are now ignored in coverage reporting.  This solves a
  few problems:

  - Coverage will no longer report about other people's code (`issue 876`_).
    This is true even when using ``--source=.`` with a venv in the current

  - Coverage will no longer generate "Already imported a file that will be
    measured" warnings about coverage itself (`issue 905`_).

- The HTML report uses j/k to move up and down among the highlighted chunks of
  code.  They used to highlight the current chunk, but 5.0 broke that behavior.
  Now the highlighting is working again.

- The JSON report now includes ``percent_covered_display``, a string with the
  total percentage, rounded to the same number of decimal places as the other
  reports' totals.

.. _issue 876: nedbat/coveragepy#876
.. _issue 905: nedbat/coveragepy#905
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