Allow use of system-installed third-party ECMAScript libraries

[nedbat]

Originally reported by Ben Finney (Bitbucket: bignose, GitHub: bignose)

---

Please allow the generated HTML report to use the system-installed version of ECMAScript libraries, instead of the ones bundled in Coverage.

While bundling third-party libraries can be convenient for some users who don't have the libraries on their system, Coverage should prefer the system-installed version of these libraries if the user indicates they exist.

The third-party ECMAScript libraries currently bundled (as of Coverage 3.6):

• jQuery
• jquery-hotkeys
• jquery-isonscreen
• jquery-tablesorter

These are all packaged in Debian at least, and installing a different version of these libraries for use only with Coverage is sub-optimal on such a system.

Specifically, the generation of an HTML report should use the system-installed instance of the above libraries.

---

• Bitbucket: https://bitbucket.org/ned/coveragepy/issue/259
• This issue had attachments: 02.use-system-ecmascript-libraries.patch. See the original issue for details.

[nedbat]

Original comment by Ben Finney (Bitbucket: bignose, GitHub: bignose)

---

This is a Coverage code patch, proposed for use in Debian's ‘python-coverage’ package, version 3.6-1.

[nedbat]

Original comment by Ben Finney (Bitbucket: bignose, GitHub: bignose)

---

I'm open to discussing what configuration or installation hooks the user has to tell Coverage to use the system-installed libraries.

The patch used by Debian is only applicable where the system libraries exist, and are in a specific location, and there is no option needed to use the bundled libraries. Some more generally-useful solution is needed.

[nedbat]

Original comment by Ben Finney (Bitbucket: bignose, GitHub: bignose)

---

Updated patch fixing a bug in copying resource files.

[nedbat]

Completed (in a different way) in e41fd0a7204d (bb).