Max Brunsfeld
e67c44a562
### Summary
This PR fixes a bug that @as-cii and @osiewicz saw when the on-disk
contents of files changed due to running `git checkout` at the command
line. It caused a buffer's contents to diverge from the file's on disk
contents, but the buffer to show an *unmodified* status.
I've also introduced new APIs on gpui's deterministic executor, which
make it possible to write a test that reliably triggered the bug.
### Details
The bug is triggered by the following sequence of events:
1. A buffer's file changes on disk while the buffer is *unmodified*
2. Zed reloads the new content of the file
3. Before updating the buffer itself, Zed computes a *diff* between the
buffer's current contents, and the newly-loaded contents
4. While this diff is being computed, one of two things happens:
1. the buffer changes on-disk *again*.
2. the user edits the buffer, but undoes the edit, so that the buffer
returns to an unmodified state
The bug itself was caused by a few things:
* The buffer diffing algorithm is pretty slow, because we perform a
character-wise diff
* We previously allowed multiple reload tasks to run concurrently
* When discarding an out-of-date diff, we failed to update parts of the
buffer's state (`saved_fingerprint`) which allow us to recognize that
the buffer's content differs from the file.
It was also difficult to reproduce the problem in tests, because under
deterministic execution, because it was extremely unlikely for other
tasks to make progress *after* a file had been reloaded, but *before*
the disk task has resolved. To help with testing, I introduced a pair of
executor APIs:
`spawn_labeled`, - for spawning a background task with a given *label*
`deprioritize_task` - for forcing tasks with a given label to run
*after* all other concurrent tasks.
I also made the `Model::next_event` test helper method more useful, in
that it no longer runs *until* parked in order to wait for the next
event to occur. It just steps the executor one poll at a time until the
model emits an event.
Release Notes:
- Fixed a bug that caused buffers to report incorrect modified/conflict
status when their buffers changed on disk multiple times in rapid
succession.
Zed
Welcome to Zed, a lightning-fast, collaborative code editor that makes your dreams come true.
Development tips
Dependencies
-
Install Xcode from https://apps.apple.com/us/app/xcode/id497799835?mt=12, and accept the license:
sudo xcodebuild -license -
Install homebrew, node and rustup-init (rustup, rust, cargo, etc.)
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)" brew install node rustup-init rustup-init # follow the installation steps -
Install postgres and configure the database
brew install postgresql@15 brew services start postgresql@15 psql -c "CREATE ROLE postgres SUPERUSER LOGIN" postgres psql -U postgres -c "CREATE DATABASE zed" -
Install the
LiveKitserver, thePostgRESTAPI server, and theforemanprocess supervisor:brew install livekit brew install postgrest brew install foreman -
Ensure the Zed.dev website is checked out in a sibling directory and install its dependencies:
cd .. git clone https://github.com/zed-industries/zed.dev cd zed.dev && npm install npm install -g vercel -
Return to Zed project directory and Initialize submodules
cd zed git submodule update --init --recursive -
Set up a local
zeddatabase and seed it with some initial users:Create a personal GitHub token to run
script/bootstraponce successfully: the token needs to have an access to private repositories for the script to work (repoOAuth scope). Then delete that token.GITHUB_TOKEN=<$token> script/bootstrap -
Now try running zed with collaboration disabled:
cargo run
Common errors
xcrun: error: unable to find utility "metal", not a developer tool or in PATH- You need to install Xcode and then run:
xcode-select --switch /Applications/Xcode.app/Contents/Developer - (see https://github.com/gfx-rs/gfx/issues/2309)
- You need to install Xcode and then run:
Testing against locally-running servers
Start the web and collab servers:
foreman start
If you want to run Zed pointed at the local servers, you can run:
script/zed-local
Dump element JSON
If you trigger cmd-alt-i, Zed will copy a JSON representation of the current window contents to the clipboard. You can paste this in a tool like DJSON to navigate the state of on-screen elements in a structured way.
Licensing
We use cargo-about to automatically comply with open source licenses. If CI is failing, check the following:
- Is it showing a
no license specifiederror for a crate you've created? If so, addpublish = falseunder[package]in your crate's Cargo.toml. - Is the error
failed to satisfy license requirementsfor a dependency? If so, first determine what license the project has and whether this system is sufficient to comply with this license's requirements. If you're unsure, ask a lawyer. Once you've verified that this system is acceptable add the license's SPDX identifier to theacceptedarray inscript/licenses/zed-licenses.toml. - Is
cargo-aboutunable to find the license for a dependency? If so, add a clarification field at the end ofscript/licenses/zed-licenses.toml, as specified in the cargo-about book.
Wasm Plugins
Zed has a Wasm-based plugin runtime which it currently uses to embed plugins. To compile Zed, you'll need to have the wasm32-wasi toolchain installed on your system. To install this toolchain, run:
rustup target add wasm32-wasi
Plugins can be found in the plugins folder in the root. For more information about how plugins work, check the Plugin Guide in crates/plugin_runtime/README.md.