Could not find `Cargo.toml` when building a dependent crate from GitHub

Question

I'm trying to use the rust-mosquitto library. My current Cargo.toml is:

[package]
name = "HomeDaemon"
version = "0.1.0"
authors = ["RTR <[email protected]>"]

[dependencies.mosquitto]
git = "https://github.com/kteza1/rust-mosquitto"

When I run cargo build, following error is reported:

Could not find `Cargo.toml` in `/Users/ravitejareddy/.cargo/git/checkouts/rust-mosquitto-8203e77dcf072bf7/rust-mosquitto`

The actual download in ~/.cargo/git/checkouts/rust-mosquitto-8203e77dcf072bf7/master shows that Cargo.toml is present.

There is an extra rust-mosquitto in the path above, is that a problem?

Hammerhead

Answer 1

The problem comes from your Cargo.toml in examples/ticktock:

[dependencies.mosquitto]
version = "*"
path = "../../../rust-mosquitto" 

When downloading your project from git, all the subdirectories are scanned for more Cargo.toml files. If you run RUST_LOG=trace cargo build -v, you see what's happening:

TRACE:cargo::ops::cargo_read_manifest: looking for root package: /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master, source_id=https://github.com/kteza1/rust-mosquitto#7e08a291
TRACE:cargo::ops::cargo_read_manifest: looking for child package: /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master
TRACE:cargo::ops::cargo_read_manifest: read_package; path=/Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/Cargo.toml; source-id=https://github.com/kteza1/rust-mosquitto#7e08a291
TRACE:cargo::ops::cargo_read_manifest: looking for child package: /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/.git
TRACE:cargo::ops::cargo_read_manifest: not processing /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/.git
TRACE:cargo::ops::cargo_read_manifest: looking for child package: /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/examples
TRACE:cargo::ops::cargo_read_manifest: looking for child package: /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/examples/c-mosquitto
TRACE:cargo::ops::cargo_read_manifest: looking for child package: /Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/examples/ticktock
TRACE:cargo::ops::cargo_read_manifest: read_package; path=/Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/master/examples/ticktock/Cargo.toml; source-id=https://github.com/kteza1/rust-mosquitto#7e08a291
DEBUG:cargo: handle_error; err=CliError { error: ChainedError { error: Unable to update https://github.com/kteza1/rust-mosquitto, cause: Could not find `Cargo.toml` in `/Users/shep/.cargo/git/checkouts/rust-mosquitto-77eb7033f32b19c9/rust-mosquitto` }, unknown: false, exit_code: 101 }

Cargo then tries to ensure that the nested Cargo.toml can have all of the dependencies satisfied.

Increscent

@tez: Because you go up three directories, when there are only two in the repository. You're effectively requiring that your repository always be checked out with the name rust-mosquitto and nothing else. – Schwinn

Ok. The folder structure is different while downloading from git where Cargo.toml resides inside branch name. 'master' in this case. – Hammerhead

Answer 2

This does not specifically answer the question that @tez asked, but I encountered the same error with a slightly different root culprit. I was writing some simple code in vim, so I created a simple main.rs file. When I cargo run it, it was spitting out the same error:

error: could not find Cargo.toml in /Users/yvonmanzi/Documents/Rust or any parent directory

The surprising thing, without the hindsight, of course, was that rustc main.rs was creating a binary executable as expected while cargo run wasn't. It turns out I had created all my rust packages(aka projects) up to that point using cargo new project-name --bin as shown here, thus by default including Cargo.lock, Cargo.toml, and src folder. Hopefully, it is clear by now that mine was just a simple rookie mistake; I simply, quite literally, didn't have Cargo.toml in my project folder. So, dear fellow rooky league Rustacean, if you get the same error, create your project with cargo new project-name --bin command.

Condensate

If this contains a separate question and answer you can post it as a separate question and then self answer it. If very relevant when you have enough reputation to post comments you could even leave a comment on this question referencing the related question. – Handtomouth

I think a correction is needed; both your "mistake" and "recommendations" presently show to use, cargo new project-name --bin to create a project. – Molal

Answer 3

run this on terminal ->

sudo find / -name Cargo.toml

this will find the path of the file

then run ->

cd <the path of the file (ofc excluding the file itself)>

now cargo is working for me

Understudy

Answer 4

On git hub, I found the answer for this problem. There was a small couple of line script I created, chmodded it, then ran it. It worked perfectly! Here is the script:

cargo install --list | 
awk '/^\w/ { print $1 }' | 
while read x; do cargo install "$x"; done

I didn't change a thing. Make sure you run it from $HOME/.cargo One of the best, shortest answers I have ever found!

Charmaincharmaine

Wha- This just cargo install's the packages you've already cargo install'd. Is there are package you were using that was out of date? – Prologize

Answer 5

The problem I figured was that I wasn't running the command in the correct directory.

1. After running the "cargo new <proj_name>"
2. you need to cd into your <proj_name> directory/folder and
3. then execute "cargo run" command.

Note: I tried running "cargo run <proj_name>" to see if it could run from outside the folder, but failed. I believe the cargo is looking in current directory for pom file.

Richter

Answer 6

The issue lies in executing the command in the wrong directory.
Following the "cargo new project_name --bin" command,
it is essential to navigate or change the directory ("cd") into the "project_name" directory before running the subsequent command, which is triggering the error.

Tenter

Answer 7

Windows 10

I tried all the steps here and it didn't work.

1. I created a project LearnRust with the recommended command:

   cargo new LearnRust --bin

2. I change directory (CD) to the LearnRust directory

3. I did the cargo run & cargo build, both work but F5 to debug the app fails with the error: Could not find Cargo.toml even though the file is in the directory!

In the Rust VsCode instructions it says:

To start debugging, you will first need to install one of two language extension with debugging support:

Microsoft C++ (ms-vscode.cpptools) – on Windows
Code LLDB (vadimcn.vscode-lldb) – on macOS/Linux

If you forget to install one of these extensions rust-analyzer will provide a notification with links to the VS Code Marketplace when you try to start a debug session.

The notification didn't appear for me and it's misleading that it says need to install one of two language extensions however since it also said If you forget to install one of these extensions I decided to install the "CodeLLDB" VsCode Extension by Vadim Chugunov as well as the C++.

launch.json

{
    "version": "0.2.0",
    "configurations": [
      {
        "name": "Debug",
        "type": "lldb",
        "request": "launch",
        "program": "${workspaceFolder}/target/debug/LearnRust.exe",
        "args": [],
        "cwd": "${workspaceFolder}",
        "preLaunchTask": "cargo build",
        "stopOnEntry": false,
        "sourceLanguages": ["rust"]
      }
    ]
  }

tasks.json

{
    "version": "2.0.0",
    "tasks": [
        {
            "type": "cargo",
            "command": "build",
            "problemMatcher": [
                "$rustc"
            ],
            "group": "build",
            "label": "rust: cargo build"
        }
    ]
}

F5 and it works:

Tip:

When you make code changes you need to cargo build otherwise you end up debugging assembly code, not the .rs file.

Forehanded

This answer looks tangential at best. OP's issue is not in regards to debugging but rather predicated on a git repository and resolved by fixing a path dependency. Just because your solution addresses a "Could not find Cargo.toml" error doesn't mean its related. Perhaps you should post this as an answer to some separate question more focused on vscode debugging; crafting the question yourself if there's not one already out there. – Prologize

I appreciate your advice - as you can see first time Rust user - feel free to edit - I'm just trying to help others who follow the standard default tutorial and hit this error and on google get this page as the first result. There's many questions on here that have different root causes. – Forehanded

To prove it I just gave @YvonManzi a badge for his post that doesn't specifically answer this question with upvotes now doubling the accepted answer. – Forehanded

Funny you mention that since it also has a comment suggesting that it should be a separate Q&A. Though you have a point; the cat's already out of the bag with the existing answers not really focusing on the original problem. – Prologize

Answer 8

It worked after i executed those *.sh under program/scripts ( then cargo build-bp again )

Trampoline