DOC: pyreverse supported format not recognized missing puml, plantuml, mmd, etc

[ChrisKeefe]

Bug description

Some supported formats are not listed in the error messaging:

> pyreverse -ASmy -o .puml my_package/my_module.py 
parsing my_package/my_module.py...
Format: "puml" not recognized. Use one of: bmp canon cmap cmapx cmapx_np dot dot_json eps fig gd gd2 gif gtk gv ico imap imap_np ismap jpe jpeg jpg json json0 mp pdf pic plain plain-ext png pov ps ps2 svg svgz tif tiff tk vml vmlz vrml wbmp x11 xdot xdot1.2 xdot1.4 xdot_json xlib

Here, I have made the mistake of prepending a . to puml. The error output should list puml (and plantuml and mmd and vcg) as supported formats.

Without the preceding ., the command runs as expected.

Command used

`> pyreverse -ASmy -o .puml my_package/my_module.py `

Pylint output

parsing my_package/my_module.py...
Format: "puml" not recognized. Use one of: bmp canon cmap cmapx cmapx_np dot dot_json eps fig gd gd2 gif gtk gv ico imap imap_np ismap jpe jpeg jpg json json0 mp pdf pic plain plain-ext png pov ps ps2 svg svgz tif tiff tk vml vmlz vrml wbmp x11 xdot xdot1.2 xdot1.4 xdot_json xlib

Expected behavior

All supported formats are listed when user makes a typo in the -o format argument

Pylint version

> pylint --version
pylint 2.12.2
astroid 2.9.3
Python 3.8.12 | packaged by conda-forge | (default, Oct 12 2021, 21:59:51) 
[GCC 9.4.0]

OS / Environment

OpenSUSE Tumbleweed

[DudeNr33]

Thank you for the report.
This error message is not generated by pyreverse itself, but comes from the call to the dot executable.

The logic for the output format in pyreverse is as follows:

1. First, we check if the given output format can be generated directly by pyreverse - this includes VCG (vcg), PlantUML (plantuml, puml), MermaidJS (mmd, html), and DOT (dot).
2. If we receive any other output format, we generate an intermediate dot file (or .gv to be more exact, but with the same content as a .dot), and then feed it to the dot command to convert it to the given output format.

This way the user is able to directly specify an image format like png to create images directly (if Graphviz or any other form of the dot command is installed).

But I agree that this message is really confusing. It would be better if we don't just output the dot error message directly but rather build our own, and make it clearer which output formats are really supported.