Installation with syntax highlighting fails

[little-dude]

Hi,

I'm trying to install cobal with cargo install cobalt-bin --features="syntax-highlight", but the build fails:

   Compiling cobalt-bin v0.7.1               
error: no associated item named `load_defaults_newlines` found for type `syntect::parsing::SyntaxSet` in the current scope     
  --> /home/corentih/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/cobalt-bin-0.7.1/src/syntax_highlight.rs:36:21            
   |                                         
36 |         syntax_set: SyntaxSet::load_defaults_newlines(),                             
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                

error: no associated item named `load_defaults` found for type `syntect::highlighting::ThemeSet` in the current scope          
  --> /home/corentih/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/cobalt-bin-0.7.1/src/syntax_highlight.rs:37:20            
   |                                         
37 |         theme_set: ThemeSet::load_defaults()                                         
   |                    ^^^^^^^^^^^^^^^^^^^^^^^                                           

error: aborting due to 2 previous errors     

error: failed to compile `cobalt-bin v0.7.1`, intermediate artifacts can be found at `/tmp/corentih/cargo-install.URcVDaLAXnXm`

Caused by:                                   
  Could not compile `cobalt-bin`.            

[epage]

Ouch. Thanks for reporting this. I've reproduced this on my machine as well.

Things that need to be looked into

• Why this is happening
• Why was this not caught

[boxofrox]

cargo install cobalt-bin --features=syntax-highlight is building against syntect v1.7.0.

   Compiling syntect v1.7.0
   Compiling cobalt-bin v0.7.1
error: no associated item named `load_defaults_newlines` found for type `syntect::parsing::SyntaxSet` in the current scope
  --> /home/charetjc/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/cobalt-bin-0.7.1/src/syntax_highlight.rs:36:21
   |
36 |         syntax_set: SyntaxSet::load_defaults_newlines(),
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: no associated item named `load_defaults` found for type `syntect::highlighting::ThemeSet` in the current scope
  --> /home/charetjc/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/cobalt-bin-0.7.1/src/syntax_highlight.rs:37:20
   |
37 |         theme_set: ThemeSet::load_defaults()
   |                    ^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

error: failed to compile `cobalt-bin v0.7.1`, intermediate artifacts can be found at `/tmp/charetjc/cargo-install.zyGXltgtH1r4`

Caused by:
  Could not compile `cobalt-bin`.

To learn more, run the command again with --verbose.

I cloned cobalt-rs and cargo build --features=syntax-highlight succeeds and builds with syntect v1.5.0 as per the Cargo.toml. This is probably why testing did not catch the error.

If I bump the syntect version in the Cargo.toml to v1.7.0, then cargo build --features=syntax-highlight fails with the same error.

Looks like dump-load or dump-load-rs[1][2] must be added to the syntect features to compile the missing functions in v1.7.0.

[1]: https://github.com/trishume/syntect/blob/v1.7.0/src/dumps.rs#L98
[2]: https://github.com/trishume/syntect/blob/v1.7.0/src/dumps.rs#L132

Not sure why cargo install doesn't use syntect v1.5.0. Perhaps a bug with cargo install?

[boxofrox]

Not a bug in cargo.

The Cargo.toml specifies:

[dependencies.syntect]
version = "1.5"
optional = true
default-features = false
features =  ["parsing", "assets", "html", "static-onig"]

According to the cargo docs [1]...

^1.2 := >=1.2.0 <2.0.0

...and v1.7 is considered a valid and backward-compatible version in accordance with semver.org.

So, either syntect intentionally broke backwards-compatibility in v1.7.0 with the new features, or there's a bug in their #[cfg(features)] expressions, and they wanted an OR operation instead of AND? I guess compatibility depends on how semver is applied to feature flags.

syntect tries to maintain backward compatibility through its features.default, which cobalt-rs disables.

PR 84 [2] added the new dump-load* feature requirement.

[1]: http://doc.crates.io/specifying-dependencies.html#caret-requirements
[2]: trishume/syntect#84

[epage]

I find the recommendation for bins to checkin their Cargo.lock file interesting when cargo install doesn't use it. I wonder if there is something to that.

[boxofrox]

I hadn't considered that angle. Checking in Cargo.lock certainly helps consistency among developers when building the source. Seems like cargo install may be an oversight.

From a unix perspective, it makes sense for software to take advantage of the latest compatible library versions, and cargo's reliance on semver compliance would facilitate that.