use gopkg.in to make buildable with go modules and dep

[markbates]

Currently when trying to use this package with either Go modules in 1.11 or in a dep environment, the package doesn't build. This change uses the gopkg.in version of the russross/blackfriday project to ensure that the correct version of blackfriday is used.

[dmitshur]

Thanks for reporting this and sending the PR. (Please ignore the CI failure, it happens due to a current Travis CI issue.) I'd like to investigate and understand the issue better.

Can you post the commands for building this with modules in Go 1.11 and the output you get? Is it just go build, or are there some environment variables involved? The build succeeds for me with Go 1.11 Beta 3:

$ go1.11beta3 version
go version go1.11beta3 darwin/amd64
$ go1.11beta3 build github.com/shurcooL/github_flavored_markdown
$

According to https://github.com/russross/blackfriday#versions, the canonical import path of blackfriday v1 is github.com/russross/blackfriday.

[markbates]

I'm still trying to get a simple reproducible test case for modules. They don't quite work in what I could predictable way yet. :)

When working on getting Buffalo to use Go modules I do occasionally get this:

github.com/shurcooL/github_flavored_markdown
# github.com/shurcooL/github_flavored_markdown
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:71:7: const initializer blackfriday.EXTENSION_NO_INTRA_EMPHASIS | blackfriday.EXTENSION_TABLES | blackfriday.EXTENSION_FENCED_CODE | blackfriday.EXTENSION_AUTOLINK | blackfriday.EXTENSION_STRIKETHROUGH | blackfriday.EXTENSION_SPACE_HEADERS | blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK is not a constant
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:71:20: undefined: blackfriday.EXTENSION_NO_INTRA_EMPHASIS
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:72:2: undefined: blackfriday.EXTENSION_TABLES
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:73:2: undefined: blackfriday.EXTENSION_FENCED_CODE
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:74:2: undefined: blackfriday.EXTENSION_AUTOLINK
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:75:2: undefined: blackfriday.EXTENSION_STRIKETHROUGH
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:76:2: undefined: blackfriday.EXTENSION_SPACE_HEADERS
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:77:2: undefined: blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK
../../../../../development/gocode/pkg/mod/github.com/shurcoo!l/github_flavored_markdown@v0.0.0-20180602233135-8913699a52e3/main.go:93:2: undefined: blackfriday.Html

Again, still working on a small repo test case.

As for dep, its very easy to reproduce:

package main

import _ "github.com/shurcooL/github_flavored_markdown"

func main() {}

$ dep init

$ go build
# github.com/gobuffalo/gfmd/vendor/github.com/shurcooL/github_flavored_markdown
vendor/github.com/shurcooL/github_flavored_markdown/main.go:71:7: const initializer blackfriday.EXTENSION_NO_INTRA_EMPHASIS | blackfriday.EXTENSION_TABLES | blackfriday.EXTENSION_FENCED_CODE | blackfriday.EXTENSION_AUTOLINK | blackfriday.EXTENSION_STRIKETHROUGH | blackfriday.EXTENSION_SPACE_HEADERS | blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK is not a constant
vendor/github.com/shurcooL/github_flavored_markdown/main.go:71:20: undefined: blackfriday.EXTENSION_NO_INTRA_EMPHASIS
vendor/github.com/shurcooL/github_flavored_markdown/main.go:72:2: undefined: blackfriday.EXTENSION_TABLES
vendor/github.com/shurcooL/github_flavored_markdown/main.go:73:2: undefined: blackfriday.EXTENSION_FENCED_CODE
vendor/github.com/shurcooL/github_flavored_markdown/main.go:74:2: undefined: blackfriday.EXTENSION_AUTOLINK
vendor/github.com/shurcooL/github_flavored_markdown/main.go:75:2: undefined: blackfriday.EXTENSION_STRIKETHROUGH
vendor/github.com/shurcooL/github_flavored_markdown/main.go:76:2: undefined: blackfriday.EXTENSION_SPACE_HEADERS
vendor/github.com/shurcooL/github_flavored_markdown/main.go:77:2: undefined: blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK
vendor/github.com/shurcooL/github_flavored_markdown/main.go:93:2: undefined: blackfriday.Html

[dmitshur]

Okay, I can reproduce with modules. I have an alternate fix in mind, please take a look at #22 and let me know what you think.

[markbates]

That fixes it for modules, but not for dep.

…

-- Mark Bates

On Sep 23, 2018, 7:18 PM -0400, Dmitri Shuralyov ***@***.***>, wrote: Okay, I can reproduce with modules. I have an alternate fix in mind, please take a look at #22 and let me know what you think. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[rtfb]

Wouldn't a Gopkg.toml with a constraint solve this for dep?

[[constraint]]
  name = "github.com/russross/blackfriday"
  version = "<2.0.0"