feat(icons): filetype detection via shebang by nobe4 · Pull Request #618 · stevearc/oil.nvim

nobe4 · 2025-04-13T19:20:25Z

This PR adds a step in the columns making: read the first line of the file and use that to compute a "fallback" filetype in case the filename alone cannot be used to determine the filetype.

This is then passed to the IconProvider which uses it if the icon is nil, or default.

This works well in initial tests, but vim.fn.readfile(name, '', 1) only read files in the current folder, I need to understand how I can make that work when changing folders. However, once this is done, I think this will provide some nice additional icons.

Looking forward to getting a review/suggestions :)

stevearc

I mentioned this in the issue, but performance is a concern here. Passing a max lines of 1 to readfile is helpful, but this will still slow us down in large directories because we'll have to open a lot of files. Could we maybe put this behind a config option so the default behavior is still fast?

stevearc · 2025-06-01T18:29:32Z

lua/oil/util.lua

+      if icon == nil or is_default then
+        icon, hl = mini_icons.get("filetype", ft or "")
+      end


Probably should only do this when ft is non-nil, right?

Actually, I think for both devicons and MiniIcons it makes sense to use the filetype first if it's provided, as that implementation should both be faster and more correct, and only use the original logic if the filetype is nil.

I have pushed some commits to address this, thanks for the suggestion!

@stevearc

As @stevearc mentioned, it would be better to use the ft directly if the function gets it, and fallback to the original logic otherwise. cc stevearc#618 (comment)

Upon looking at devicons' code, it seems that passing `ft` even when nil will result in the same execution, and doing otherwise won't create any performance improvements.

@stevearc

As @stevearc suggested, it would be better to keep the default behavior for performance reasons. Adding a config option to enable the ft detection ensures this. cc stevearc#618 (review)

nobe4 · 2025-06-02T07:27:09Z

lua/oil/columns.lua

+
+      local ft = ""
+      if field_type == "file" then
+        local firstline = vim.fn.readfile(name, '', 1)


@stevearc, I have searched, and failed to find how to get absolute filepaths, or the current directory in the context of this function. Do you know how I can get it?

The render function takes a bufnr as the third argument

oil.nvim/lua/oil/columns.lua

Line 15 in 685cdb4

---@field render fun(entry: oil.InternalEntry, conf: nil|table, bufnr: integer): nil|oil.TextChunk

You could parse the buffer name to get the parent dir like we do here

oil.nvim/lua/oil/adapters/files.lua

Lines 506 to 507 in 685cdb4

local bufname = vim.api.nvim_buf_get_name(bufnr)

local _, path = util.parse_url(bufname)

Awesome! Thanks for this!

Done in e2ad451

The ft is compared against `nil` in the rest of the code, so don't set it up to an empty string if missing.

`get_icon` favor the filename instead of the `ft`, so we need to use `get_icon_by_filetype` to explicitly make the ft a priority. This commits leaves the normal logic as a fallback if the icon is not found with the filetype.

stevearc · 2025-06-04T00:38:48Z

lua/oil/config.lua

+    -- Read the first line of the file and use vim's matching ft.
+    -- Can slow down the execution considerably for large projects.
+    use_vim_ft = false,


Could we instead make this an option for the icon column, like we do for add_padding? You can just access it on the conf table like conf.use_slow_filetype_detection and then add an entry to this file to generate the documentation for it.

Done in 2aa7176

This uses the current oil buffer's path.

Problem: files without standard extensions (e.g. scripts with shebangs, Makefile, Dockerfile) got incorrect or default icons since icon providers match by filename or extension only. Solution: add use_slow_filetype_detection option to the icon column config. When enabled, reads the first 16 lines of each file and passes them to vim.filetype.match for content-based detection. The detected filetype is forwarded to mini.icons or nvim-web-devicons as a trailing parameter, preserving backwards compatibility with existing icon provider implementations. Based on: stevearc#618

Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files.

#123) Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * docs(upstream): mark stevearc#707 as duplicate of #117 Problem: Issue stevearc#707 (move file/dir into new dir by renaming) was listed as `open` despite being identical to #117. The associated draft PR stevearc#708 is already tracked separately in the PRs table. Solution: Update status to `duplicate of #117`.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * docs(upstream): mark stevearc#707 as duplicate of #117 Problem: Issue stevearc#707 (move file/dir into new dir by renaming) was listed as `open` despite being identical to #117. The associated draft PR stevearc#708 is already tracked separately in the PRs table. Solution: Update status to `duplicate of #117`. * docs(upstream): consolidate owner/group issues into #126 Problem: Three upstream issues (stevearc#436, stevearc#599, stevearc#684) all request the same feature — owner/group columns in the directory listing. Solution: Create canonical tracking issue #126 and mark all three as `consolidated into #126`.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * docs(upstream): mark stevearc#707 as duplicate of #117 Problem: Issue stevearc#707 (move file/dir into new dir by renaming) was listed as `open` despite being identical to #117. The associated draft PR stevearc#708 is already tracked separately in the PRs table. Solution: Update status to `duplicate of #117`. * docs(upstream): consolidate owner/group issues into #126 Problem: Three upstream issues (stevearc#436, stevearc#599, stevearc#684) all request the same feature — owner/group columns in the directory listing. Solution: Create canonical tracking issue #126 and mark all three as `consolidated into #126`. * docs(upstream): mark stevearc#570 not actionable Problem: Issue stevearc#570 (`c0`/`d0` deletes concealed entry ID prefix, causing rename to be parsed as delete+create) was listed as `open`. Solution: Mark as `not actionable — blocked on Neovim extmark API`. Neovim provides no mechanism to protect concealed extmark text from operator-pending motions. The intended rename workflow uses `cw`/`ciw` within the constrained cursor region.

#123) Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * docs(upstream): mark stevearc#707 as duplicate of #117 Problem: Issue stevearc#707 (move file/dir into new dir by renaming) was listed as `open` despite being identical to #117. The associated draft PR stevearc#708 is already tracked separately in the PRs table. Solution: Update status to `duplicate of #117`.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * docs(upstream): mark stevearc#707 as duplicate of #117 Problem: Issue stevearc#707 (move file/dir into new dir by renaming) was listed as `open` despite being identical to #117. The associated draft PR stevearc#708 is already tracked separately in the PRs table. Solution: Update status to `duplicate of #117`. * docs(upstream): consolidate owner/group issues into #126 Problem: Three upstream issues (stevearc#436, stevearc#599, stevearc#684) all request the same feature — owner/group columns in the directory listing. Solution: Create canonical tracking issue #126 and mark all three as `consolidated into #126`.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * docs(upstream): mark stevearc#707 as duplicate of #117 Problem: Issue stevearc#707 (move file/dir into new dir by renaming) was listed as `open` despite being identical to #117. The associated draft PR stevearc#708 is already tracked separately in the PRs table. Solution: Update status to `duplicate of #117`. * docs(upstream): consolidate owner/group issues into #126 Problem: Three upstream issues (stevearc#436, stevearc#599, stevearc#684) all request the same feature — owner/group columns in the directory listing. Solution: Create canonical tracking issue #126 and mark all three as `consolidated into #126`. * docs(upstream): mark stevearc#570 not actionable Problem: Issue stevearc#570 (`c0`/`d0` deletes concealed entry ID prefix, causing rename to be parsed as delete+create) was listed as `open`. Solution: Mark as `not actionable — blocked on Neovim extmark API`. Neovim provides no mechanism to protect concealed extmark text from operator-pending motions. The intended rename workflow uses `cw`/`ciw` within the constrained cursor region.

* docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`.

* docs(upstream): mark stevearc#675 as duplicate of #117 (#124) * docs(upstream): mark stevearc#617 fixed via cherry-picked stevearc#618 Problem: Issue stevearc#617 (filetype-based icon detection) was still listed as `open` in the upstream tracker despite being addressed by PR stevearc#618. Solution: Update status to `fixed — cherry-picked (stevearc#618)`. Verified with manual testing that `use_slow_filetype_detection` correctly detects shebangs in extensionless files. * docs(upstream): mark stevearc#675 as duplicate of #117 Problem: Issue stevearc#675 (move file into folder by renaming) was listed as `open` despite being a duplicate of #117, the primary tracking issue for move-by-rename (46 upvotes). Upstream already closed stevearc#675 as such. Solution: Update status to `duplicate of #117`. * fix(float): support `close = false` for floating oil windows Problem: `select` with `close = false` was broken for floating oil windows. The float auto-close autocmd would always close the window when focus left, and there was no mechanism to preserve it. Solution: Add `oil_keep_open` window flag set when `close = false` is used on a float. The auto-close autocmd checks this flag before closing. On file select, focus returns to the original window behind the float so the file opens there, then focus restores to the float. * docs(upstream): mark stevearc#399 as fixed (#159)

nobe4 added 2 commits April 13, 2025 12:17

test(files): try to load the ft from the first line of the file

64bf652

feat(utils): make the icon provider default to the specified filetype

a44861f

github-actions bot requested a review from stevearc April 13, 2025 19:20

stevearc requested changes Jun 1, 2025

View reviewed changes

nobe4 added 4 commits June 2, 2025 08:57

refactor(util): get icon, hl from ft if specified

16f815c

As @stevearc mentioned, it would be better to use the ft directly if the function gets it, and fallback to the original logic otherwise. cc stevearc#618 (comment)

refactor(util): simplify the devicons logic

9dadbe0

Upon looking at devicons' code, it seems that passing `ft` even when nil will result in the same execution, and doing otherwise won't create any performance improvements.

feat(config): add key to toggle ft detection

26379d3

As @stevearc suggested, it would be better to keep the default behavior for performance reasons. Adding a config option to enable the ft detection ensures this. cc stevearc#618 (review)

docs(config): add field definition

3b7ba05

nobe4 commented Jun 2, 2025

View reviewed changes

github-actions bot requested a review from stevearc June 2, 2025 07:27

nobe4 added 2 commits June 2, 2025 09:35

refactor(columns): leave ft to nil

e0018c8

The ft is compared against `nil` in the rest of the code, so don't set it up to an empty string if missing.

refactor(util): improve devicons' usage

73ff8d8

`get_icon` favor the filename instead of the `ft`, so we need to use `get_icon_by_filetype` to explicitly make the ft a priority. This commits leaves the normal logic as a fallback if the icon is not found with the filetype.

stevearc reviewed Jun 4, 2025

View reviewed changes

refactor(config): add the key in the generated config

2aa7176

github-actions bot requested a review from stevearc June 4, 2025 08:50

nobe4 added 3 commits June 4, 2025 10:51

docs: generate the documentation for the new option

26fc586

fix(column): load file from absolute path

e2ad451

This uses the current oil buffer's path.

fix(lint): format

8ccee95

barrettruth mentioned this pull request Feb 20, 2026

feat(icon): add opt-in filetype detection via file contents barrettruth/canola.nvim#4

Closed

barrettruth mentioned this pull request Mar 15, 2026

docs(upstream): mark #617 fixed via cherry-picked #618 barrettruth/canola.nvim#123

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feat(icons): filetype detection via shebang#618

feat(icons): filetype detection via shebang#618
nobe4 wants to merge 12 commits intostevearc:masterfrom
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	local bufname = vim.api.nvim_buf_get_name(bufnr)
	local _, path = util.parse_url(bufname)

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