Improve importing, fix importing panic

[kevinburke]

Steps to reproduce (maybe?)

• set JUPYTER_CONFIG_DIR to $HOME/cfg/jupyter
• set JUPYTER_DATA_DIR to $HOME/local/share/jupyter
• run go install ./... (I'm using go1.7)

start Jupyter Notebook, start a Golang notebook

type the following

 import "fmt"
fmt.Println("Hello World")

Then hit shift+enter. I get the following panic:

panic: exit status 2

goroutine 1 [running]:
panic(0x42ebe80, 0xc420288f60)
    /Users/kevin/go/src/runtime/panic.go:500 +0x1a1
github.com/gopherds/gophernotes/internal/repl.(*Session).Eval(0xc4200ac370, 0xc420284c90, 0x27, 0xc42022d498, 0xc420286d70, 0x8, 0xc420288500, 0x0, 0x0, 0x0, ...)
    /Users/kevin/code/go/src/github.com/gopherds/gophernotes/internal/repl/repl.go:355 +0xc01
main.HandleExecuteRequest(0xc4202884e0, 0x20, 0xc420286c98, 0x8, 0xc420288500, 0x20, 0xc420286ca0, 0xf, 0x0, 0x0, ...)
    /Users/kevin/code/go/src/github.com/gopherds/gophernotes/execution.go:60 +0x2f3
main.HandleShellMsg(0xc4202884e0, 0x20, 0xc420286c98, 0x8, 0xc420288500, 0x20, 0xc420286ca0, 0xf, 0x0, 0x0, ...)
    /Users/kevin/code/go/src/github.com/gopherds/gophernotes/gophernotes.go:108 +0x2c7
main.RunKernel(0x7fff5fbff495, 0x59, 0x44ab360, 0xc4200142a8)
    /Users/kevin/code/go/src/github.com/gopherds/gophernotes/gophernotes.go:194 +0x836
main.main()
    /Users/kevin/code/go/src/github.com/gopherds/gophernotes/main.go:25 +0xc6

Haven't investigated it at all.

[kevinburke]

More debugging info:

Error running goimports:
/var/folders/dx/x6gx95t14n7bb3v878968fkm0000gn/T/448556322/func_proxy.go:5:1: expected declaration, found 'IDENT' fmt
panic: exit status 2

It would be nice to surface that in the UI somehow

[dwhitena]

I think the problem here is the import. As of now you need to use :import to import. However, we should just throw an error or message if we get the import without the colon, not panic. Thanks!

[dwhitena]

#35 allows a user to have more insight into this error. However, we should improve the importing process, such that this doesn't crash the kernel.

[dwhitena]

Also, we should improve imports, as multiple imports in the same cell can result in error.

[kevinburke]

multiple imports in the same cell can result in error.

Ah, I just hit this.

This fails:

:import "time"
:import "fmt"
t := time.Time{}
fmt.Println(t.IsZero())
t.IsZero()

with the following message in the terminal:

$ jupyter notebook
[I 10:32:50.249 NotebookApp] Serving notebooks from local directory: /Users/kevin/code/go/src/github.com/kevinburke/go-notebooks
[I 10:32:50.251 NotebookApp] 0 active kernels
[I 10:32:50.251 NotebookApp] The Jupyter Notebook is running at: http://localhost:8888/
[I 10:32:50.251 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[W 10:32:54.140 NotebookApp] 404 GET /api/kernels/c25e3582-c84b-4e46-a2c7-d35ecfc6058d/channels?session_id=D5E3D94A13E040CDAA2F3C2D1F669EFC (::1): Kernel does not exist: c25e3582-c84b-4e46-a2c7-d35ecfc6058d
[W 10:32:54.236 NotebookApp] 404 GET /api/kernels/c25e3582-c84b-4e46-a2c7-d35ecfc6058d/channels?session_id=D5E3D94A13E040CDAA2F3C2D1F669EFC (::1) 163.82ms referer=None
[W 10:33:03.351 NotebookApp] 404 GET /nbextensions/widgets/notebook/js/extension.js (::1) 15.83ms referer=http://localhost:8888/notebooks/Untitled.ipynb
[I 10:33:03.741 NotebookApp] Kernel started: 7d3a8201-0b07-4576-8893-27409f786da4
[I 10:33:15.760 NotebookApp] Kernel shutdown: 7d3a8201-0b07-4576-8893-27409f786da4
[I 10:33:15.901 NotebookApp] Kernel started: ad224100-35e3-49ba-a536-727aabeb1c3d
[I 10:33:16.129 NotebookApp] Adapting to protocol v4.0 for kernel ad224100-35e3-49ba-a536-727aabeb1c3d
error: import: can't find import:
error: import: can't find import:

Should I open a different ticket?

[dwhitena]

@kevinburke No, I'm working on this now and will address in this ticket. I've got multiple imports working, just checking a few things. Will PR soon.

[dwhitena]

@kevinburke Addressed by #36

[dwhitena]

Closing.