Reflow doesn't work consistently with comments

[bcspragu]

Summary

Most of the time, when I select a comment (e.g. with x) and run :reflow, the comment prefix (e.g. //) isn't added to the reflowed lines. It seems to happen most when reflowing a single line into multiple lines.

Reproduction Steps

I tried creating a basic Go file, the LSP functionality is working correctly in this file (in case that matters).

After selecting the comment and running :reflow, I expected this to happen:

Instead, this happened (ignore the difference in highlighting)

Helix log

~/.cache/helix/helix.log

2022-08-04T12:02:40.098 helix_view::clipboard [INFO] Using xclip to interact with the system and selection (primary) clipboard
2022-08-04T12:02:40.104 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","method":"initialize","params":{"capabilities":{"textDocument":{"codeAction":{"codeActionLiteralSupport":{"codeActionKind":{"valueSet":["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}}},"completion":{"completionItem":{"resolveSupport":{"properties":["documentation","detail","additionalTextEdits"]},"snippetSupport":false},"completionItemKind":{}},"hover":{"contentFormat":["markdown"]},"publishDiagnostics":{},"rename":{"dynamicRegistration":false,"honorsChangeAnnotations":false,"prepareSupport":false},"signatureHelp":{"signatureInformation":{"activeParameterSupport":true,"documentationFormat":["markdown"],"parameterInformation":{"labelOffsetSupport":true}}}},"window":{"workDoneProgress":true},"workspace":{"applyEdit":true,"configuration":true,"didChangeConfiguration":{"dynamicRegistration":false},"workspaceFolders":true}},"processId":10781,"rootPath":"/home/$USER/test","rootUri":"file:///home/$USER/test","workspaceFolders":[{"name":"test","uri":"file:///home/$USER/test"}]},"id":0}
2022-08-04T12:02:40.172 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","result":{"capabilities":{"textDocumentSync":{"openClose":true,"change":2,"save":{}},"completionProvider":{"triggerCharacters":["."],"completionItem":{}},"hoverProvider":true,"signatureHelpProvider":{"triggerCharacters":["(",","]},"definitionProvider":true,"typeDefinitionProvider":true,"implementationProvider":true,"referencesProvider":true,"documentHighlightProvider":true,"documentSymbolProvider":true,"codeActionProvider":{"codeActionKinds":["quickfix","refactor.extract","refactor.rewrite","source.fixAll","source.organizeImports"]},"codeLensProvider":{},"documentLinkProvider":{},"workspaceSymbolProvider":true,"documentFormattingProvider":true,"documentOnTypeFormattingProvider":{"firstTriggerCharacter":""},"renameProvider":true,"foldingRangeProvider":true,"executeCommandProvider":{"commands":["gopls.add_dependency","gopls.add_import","gopls.apply_fix","gopls.check_upgrades","gopls.edit_go_directive","gopls.gc_details","gopls.generate","gopls.generate_gopls_mod","gopls.go_get_package","gopls.list_imports","gopls.list_known_packages","gopls.regenerate_cgo","gopls.remove_dependency","gopls.run_tests","gopls.run_vulncheck_exp","gopls.start_debugging","gopls.test","gopls.tidy","gopls.toggle_gc_details","gopls.update_go_sum","gopls.upgrade_dependency","gopls.vendor"]},"callHierarchyProvider":true,"workspace":{"workspaceFolders":{"supported":true,"changeNotifications":"workspace/didChangeWorkspaceFolders"}},"inlayHintProvider":{}},"serverInfo":{"name":"gopls","version":"{\"GoVersion\":\"go1.18.4\",\"Path\":\"golang.org/x/tools/gopls\",\"Main\":{\"Path\":\"golang.org/x/tools/gopls\",\"Version\":\"v0.9.1\",\"Sum\":\"h1:SigsTL4Hpv3a6b/a7oPCLRv5QUeSM6PZNdta1oKY4B0=\",\"Replace\":null},\"Deps\":[...removed...],\"Settings\":[{\"Key\":\"-compiler\",\"Value\":\"gc\"},{\"Key\":\"CGO_ENABLED\",\"Value\":\"1\"},{\"Key\":\"CGO_CFLAGS\",\"Value\":\"\"},{\"Key\":\"CGO_CPPFLAGS\",\"Value\":\"\"},{\"Key\":\"CGO_CXXFLAGS\",\"Value\":\"\"},{\"Key\":\"CGO_LDFLAGS\",\"Value\":\"\"},{\"Key\":\"GOARCH\",\"Value\":\"amd64\"},{\"Key\":\"GOOS\",\"Value\":\"linux\"},{\"Key\":\"GOAMD64\",\"Value\":\"v1\"}],\"Version\":\"v0.9.1\"}"}},"id":0}
2022-08-04T12:02:40.173 helix_lsp::transport [INFO] <- {"capabilities":{"callHierarchyProvider":true,"codeActionProvider":{"codeActionKinds":["quickfix","refactor.extract","refactor.rewrite","source.fixAll","source.organizeImports"]},"codeLensProvider":{},"completionProvider":{"completionItem":{},"triggerCharacters":["."]},"definitionProvider":true,"documentFormattingProvider":true,"documentHighlightProvider":true,"documentLinkProvider":{},"documentOnTypeFormattingProvider":{"firstTriggerCharacter":""},"documentSymbolProvider":true,"executeCommandProvider":{"commands":["gopls.add_dependency","gopls.add_import","gopls.apply_fix","gopls.check_upgrades","gopls.edit_go_directive","gopls.gc_details","gopls.generate","gopls.generate_gopls_mod","gopls.go_get_package","gopls.list_imports","gopls.list_known_packages","gopls.regenerate_cgo","gopls.remove_dependency","gopls.run_tests","gopls.run_vulncheck_exp","gopls.start_debugging","gopls.test","gopls.tidy","gopls.toggle_gc_details","gopls.update_go_sum","gopls.upgrade_dependency","gopls.vendor"]},"foldingRangeProvider":true,"hoverProvider":true,"implementationProvider":true,"inlayHintProvider":{},"referencesProvider":true,"renameProvider":true,"signatureHelpProvider":{"triggerCharacters":["(",","]},"textDocumentSync":{"change":2,"openClose":true,"save":{}},"typeDefinitionProvider":true,"workspace":{"workspaceFolders":{"changeNotifications":"workspace/didChangeWorkspaceFolders","supported":true}},"workspaceSymbolProvider":true},"serverInfo":{"name":"gopls","version":"{\"GoVersion\":\"go1.18.4\",\"Path\":\"golang.org/x/tools/gopls\",\"Main\":{\"Path\":\"golang.org/x/tools/gopls\",\"Version\":\"v0.9.1\",\"Sum\":\"h1:SigsTL4Hpv3a6b/a7oPCLRv5QUeSM6PZNdta1oKY4B0=\",\"Replace\":null},\"Deps\":[...removed...],\"Settings\":[{\"Key\":\"-compiler\",\"Value\":\"gc\"},{\"Key\":\"CGO_ENABLED\",\"Value\":\"1\"},{\"Key\":\"CGO_CFLAGS\",\"Value\":\"\"},{\"Key\":\"CGO_CPPFLAGS\",\"Value\":\"\"},{\"Key\":\"CGO_CXXFLAGS\",\"Value\":\"\"},{\"Key\":\"CGO_LDFLAGS\",\"Value\":\"\"},{\"Key\":\"GOARCH\",\"Value\":\"amd64\"},{\"Key\":\"GOOS\",\"Value\":\"linux\"},{\"Key\":\"GOAMD64\",\"Value\":\"v1\"}],\"Version\":\"v0.9.1\"}"}}
2022-08-04T12:02:40.173 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","method":"initialized","params":{}}
2022-08-04T12:02:40.173 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"languageId":"go","text":"package main\n\nimport \"fmt\"\n\n// This is a long comment that will need to be wrapped once it is finished being written. Here is some more text and other things as well. And one more sentence so that this goes to three lines, for demonstration purposes.\nfunc main() {\n\tfmt.Println(\"Hello Helix!\")\n}\n","uri":"file:///home/$USER/test/main.go","version":0}}}
2022-08-04T12:02:40.173 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"window/workDoneProgress/create","params":{"token":"5577006791947779410"},"id":1}
2022-08-04T12:02:40.174 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","result":null,"id":1}
2022-08-04T12:02:40.174 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"$/progress","params":{"token":"5577006791947779410","value":{"kind":"begin","title":"Setting up workspace","message":"Loading packages..."}}}
2022-08-04T12:02:40.175 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"workspace/configuration","params":{"items":[{"scopeUri":"file:///home/$USER/test","section":"gopls"}]},"id":2}
2022-08-04T12:02:40.175 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","result":[null],"id":2}
2022-08-04T12:02:40.188 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"2022/08/04 12:02:40 go env for /home/$USER/test\n(root /home/$USER/test)\n(go version go version go1.19 linux/amd64)\n(valid build configuration = true)\n(build flags: [])\nGOCACHE=/home/$USER/.cache/go-build\nGOMODCACHE=/home/$USER/.local/go/pkg/mod\nGOPROXY=https://athens.$USER.com\nGOWORK=\nGO111MODULE=\nGOROOT=/usr/lib/go\nGONOPROXY=\nGOMOD=/home/$USER/test/go.mod\nGOSUMDB=sum.golang.org\nGOPATH=/home/$USER/.local/go\nGONOSUMDB=\nGOPRIVATE=\nGOFLAGS=\nGOINSECURE=\n\n"}}
2022-08-04T12:02:40.188 helix_term::application [INFO] window/logMessage: LogMessageParams { typ: Info, message: "2022/08/04 12:02:40 go env for /home/$USER/test\n(root /home/$USER/test)\n(go version go version go1.19 linux/amd64)\n(valid build configuration = true)\n(build flags: [])\nGOCACHE=/home/$USER/.cache/go-build\nGOMODCACHE=/home/$USER/.local/go/pkg/mod\nGOPROXY=https://athens.$USER.com\nGOWORK=\nGO111MODULE=\nGOROOT=/usr/lib/go\nGONOPROXY=\nGOMOD=/home/$USER/test/go.mod\nGOSUMDB=sum.golang.org\nGOPATH=/home/$USER/.local/go\nGONOSUMDB=\nGOPRIVATE=\nGOFLAGS=\nGOINSECURE=\n\n" }
2022-08-04T12:02:40.273 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"2022/08/04 12:02:40 go/packages.Load #1\n\tsnapshot=0\n\tdirectory=/home/$USER/test\n\tquery=[builtin example.com/...]\n\tpackages=2\n"}}
2022-08-04T12:02:40.273 helix_term::application [INFO] window/logMessage: LogMessageParams { typ: Info, message: "2022/08/04 12:02:40 go/packages.Load #1\n\tsnapshot=0\n\tdirectory=/home/$USER/test\n\tquery=[builtin example.com/...]\n\tpackages=2\n" }
2022-08-04T12:02:40.274 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"2022/08/04 12:02:40 go/packages.Load #1: updating metadata for 40 packages\n"}}
2022-08-04T12:02:40.274 helix_term::application [INFO] window/logMessage: LogMessageParams { typ: Info, message: "2022/08/04 12:02:40 go/packages.Load #1: updating metadata for 40 packages\n" }
2022-08-04T12:02:40.297 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"$/progress","params":{"token":"5577006791947779410","value":{"kind":"end","message":"Finished loading packages."}}}
2022-08-04T12:02:40.377 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"2022/08/04 12:02:40 falling back to safe trimming due to type errors: [/usr/lib/go/src/runtime/vdso_linux.go:53:38: invalid operation: division by zero /usr/lib/go/src/runtime/vdso_linux.go:54:38: invalid operation: division by zero] or still-missing identifiers: map[memRecordCycle:true pageBits:true]\n\tpackage=\"runtime\"\n"}}
2022-08-04T12:02:40.377 helix_term::application [INFO] window/logMessage: LogMessageParams { typ: Info, message: "2022/08/04 12:02:40 falling back to safe trimming due to type errors: [/usr/lib/go/src/runtime/vdso_linux.go:53:38: invalid operation: division by zero /usr/lib/go/src/runtime/vdso_linux.go:54:38: invalid operation: division by zero] or still-missing identifiers: map[memRecordCycle:true pageBits:true]\n\tpackage=\"runtime\"\n" }
2022-08-04T12:02:46.953 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","method":"textDocument/didChange","params":{"contentChanges":[{"range":{"end":{"character":0,"line":5},"start":{"character":0,"line":4}},"text":"// This is a long comment that will need to be wrapped once it is finished\nbeing written. Here is some more text and other things as well. And one more\nsentence so that this goes to three lines, for demonstration purposes.\n"}],"textDocument":{"uri":"file:///home/$USER/test/main.go","version":1}}}
2022-08-04T12:02:46.955 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"uri":"file:///home/$USER/test/main.go","version":1,"diagnostics":[{"range":{"start":{"line":5,"character":0},"end":{"line":5,"character":0}},"severity":1,"source":"syntax","message":"expected declaration, found being"}]}}
2022-08-04T12:02:50.197 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","method":"shutdown","params":null,"id":1}
2022-08-04T12:02:50.197 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","result":null,"id":1}
2022-08-04T12:02:50.197 helix_lsp::transport [INFO] <- null
2022-08-04T12:02:50.197 helix_lsp::transport [INFO] <- {"jsonrpc":"2.0","method":"window/logMessage","params":{"type":3,"message":"2022/08/04 12:02:50 Shutdown session\n\tshutdown_session=1\n"}}
2022-08-04T12:02:50.198 helix_lsp::transport [INFO] -> {"jsonrpc":"2.0","method":"exit","params":null}
2022-08-04T12:02:50.198 helix_lsp::transport [ERROR] err: <- StreamClosed

Platform

Linux

Terminal Emulator

st 0.8.4

Helix Version

helix 22.05 (c5f8a83)

[the-mikedavis]

The current implementation of :reflow uses common prefixes between lines rather than knowing about a language's comment token(s). So this is expected behavior when reflowing single-line comments but shouldn't happen with multiple single-line comments (block comments are also not supported yet but that's another issue).

See also #1937 which is a different feature but may be useful implementation-wise.

[bcspragu]

Thanks for the reference, that does indeed look useful. I basically just want to mimic Vim/NeoVim's behavior here, which I've rarely ever had to think about. Once #1937 lands, I can take a look into reusing that for :reflow and/or seeing if textwrap can be made to do the right thing here.

[vlmutolo]

This is a known limitation of the current version of reflow. I believe the plan is to work with the textwrap crate to allow specifying custom prefix strings. See this discussion for context.

[epbuennig]

I'd like to add that running :reflow on inner rust doc comments considered only // as the separator for me and inferred ! to be part of the text to reflow.

Running :reflow 100 here:

//! Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt
//! ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris
//! nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit
//! esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
//! culpa qui officia deserunt mollit anim id est laborum.

produces the following result:

//! Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt !
//ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco
//laboris ! nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in
//voluptate velit ! esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat
//non proident, sunt in ! culpa qui officia deserunt mollit anim id est laborum.

[k12ish]

I'd like to add that :reflow should perhaps consider separators before newlines, as in languages where \ is used as an escape sequence:

"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Phasellus sed finibus \
sem, luctus dapibus odio. Etiam a sodales quam. Suspendisse auctor, diam eget \
facilisis mattis, justo sem pellentesque quam, a bibendum purus ipsum at justo. \
Etiam odio risus, consectetur nec varius quis, semper in elit. Mauris convallis \
arcu ut elit facilisis, at pretium felis pellentesque. "

[vlmutolo]

I'd like to add that :reflow should perhaps consider separators before newlines

This is an excellent point. I hadn't considered this at all. I think the general plan for making prefix recognition more robust was to work with the textwrap library to expose an API that lets the caller specify what to consider a prefix. I think we could (probably?) allow configuration of the suffix as well.

[bonsairobo]

Is there any issue in textwrap that covers the Helix use cases mentioned here? I didn't see anything that jumped out at me. I could try pushing the ball a little further, since I consider the current :reflow functionality a time-sink for editing Rust.

[bonsairobo]

Hello again. I've had some discussion with @mgeisler in this textwrap issue to make some progress. Before we go further, I'd appreciate if a Helix maintainer could read through that issue and give a 👍 to our general path of implementation.

[the-mikedavis]

I talked about this a bit with @pascalkuthe and in the long run I think we want to transition to having custom hard-wrapping code in helix-core rather than using the textwrap crate. There's a good chance we'll be able to re-use some of what we already have for soft-wrap and we could tailor the code to the features we need and info we have available like knowing about syntax via tree-sitter and about comment tokens once #4718 is merged.

[mgeisler]

I talked about this a bit with @pascalkuthe and in the long run I think we want to transition to having custom hard-wrapping code in helix-core rather than using the textwrap crate.

I would be interested to hear if this is because the simple wrapping logic is simple enough that it can just be re-implemented?

Personally, I would love to see a real editor with support for balanced wrapping 🙂 but that's of course only if you find the feature interesting in the first place. I used LaTeX a ton at my university days, so that is why I'm fascinated by the idea of optimizing wrapping across an entire paragraph. I think it would be quite a unique selling point.

If that feature is uninteresting, then I agree that it's easy to implement normal greedy-wrapping by hand. I implemented a quick-and-dirty wrapping function here so I could compare the binary sizes of programs with and without Textwrap.