Use anyhow more idiomatically (#31052)

https://github.com/zed-industries/zed/issues/30972 brought up another
case where our context is not enough to track the actual source of the
issue: we get a general top-level error without inner error.

The reason for this was `.ok_or_else(|| anyhow!("failed to read HEAD
SHA"))?; ` on the top level.

The PR finally reworks the way we use anyhow to reduce such issues (or
at least make it simpler to bubble them up later in a fix).
On top of that, uses a few more anyhow methods for better readability.

* `.ok_or_else(|| anyhow!("..."))`, `map_err` and other similar error
conversion/option reporting cases are replaced with `context` and
`with_context` calls
* in addition to that, various `anyhow!("failed to do ...")` are
stripped with `.context("Doing ...")` messages instead to remove the
parasitic `failed to` text
* `anyhow::ensure!` is used instead of `if ... { return Err(...); }`
calls
* `anyhow::bail!` is used instead of `return Err(anyhow!(...));`

Release Notes:

- N/A

crates/eval/src/eval.rs

@@ -11,7 +11,6 @@ use instance::{ExampleInstance, JudgeOutput, RunOutput, run_git};
 pub(crate) use tool_metrics::*;
 
 use ::fs::RealFs;
-use anyhow::anyhow;
 use clap::Parser;
 use client::{Client, ProxySettings, UserStore};
 use collections::{HashMap, HashSet};
@@ -255,13 +254,10 @@ fn main() {
 
                         let actual_origin =
                             run_git(&repo_path, &["remote", "get-url", "origin"]).await?;
-                        if actual_origin != repo_url {
-                            return Err(anyhow!(
-                                "remote origin {} does not match expected origin {}",
-                                actual_origin,
-                                repo_url,
-                            ));
-                        }
+                        anyhow::ensure!(
+                            actual_origin == repo_url,
+                            "remote origin {actual_origin} does not match expected origin {repo_url}"
+                        );
                     }
                 }
             }
@@ -467,7 +463,7 @@ pub fn find_model(
 
     match matching_models.as_slice() {
         [model] => Ok(model.clone()),
-        [] => Err(anyhow!(
+        [] => anyhow::bail!(
             "No language model with ID {}/{} was available. Available models: {}",
             provider_id,
             model_id,
@@ -476,15 +472,15 @@ pub fn find_model(
                 .map(|model| format!("{}/{}", model.provider_id().0, model.id().0))
                 .collect::<Vec<_>>()
                 .join(", ")
-        )),
-        _ => Err(anyhow!(
+        ),
+        _ => anyhow::bail!(
             "Multiple language models with ID {} available - use `--provider` to choose one of: {:?}",
             model_id,
             matching_models
                 .iter()
                 .map(|model| model.provider_id().0)
                 .collect::<Vec<_>>()
-        )),
+        ),
     }
 }
 

crates/eval/src/example.rs

@@ -177,12 +177,10 @@ impl ExampleContext {
 
     fn log_assertion<T>(&mut self, result: Result<T>, message: String) -> Result<T> {
         if let Some(max) = self.meta.max_assertions {
-            if self.assertions.run_count() > max {
-                return Err(anyhow!(
-                    "More assertions were run than the stated max_assertions of {}",
-                    max
-                ));
-            }
+            anyhow::ensure!(
+                self.assertions.run_count() <= max,
+                "More assertions were run than the stated max_assertions of {max}"
+            );
         }
 
         self.assertions.ran.push(RanAssertion {
@@ -319,7 +317,7 @@ impl ExampleContext {
                     }
                 }
                 _ = self.app.background_executor().timer(THREAD_EVENT_TIMEOUT).fuse() => {
-                    return Err(anyhow!("Agentic loop stalled - waited {:?} without any events", THREAD_EVENT_TIMEOUT));
+                    anyhow::bail!("Agentic loop stalled - waited {THREAD_EVENT_TIMEOUT:?} without any events");
                 }
             }
         }

crates/eval/src/explorer.rs

@@ -1,4 +1,4 @@
-use anyhow::{Context, Result, anyhow};
+use anyhow::{Context as _, Result};
 use clap::Parser;
 use serde_json::{Value, json};
 use std::fs;
@@ -57,7 +57,7 @@ fn inject_thread_data(template: String, threads_data: Value) -> Result<String> {
     let injection_marker = "let threadsData = window.threadsData || { threads: [dummyThread] };";
     template
         .find(injection_marker)
-        .ok_or_else(|| anyhow!("Could not find the thread injection point in the template"))?;
+        .context("Could not find the thread injection point in the template")?;
 
     let threads_json = serde_json::to_string_pretty(&threads_data)
         .context("Failed to serialize threads data to JSON")?;

crates/eval/src/ids.rs

@@ -1,4 +1,4 @@
-use anyhow::{Result, anyhow};
+use anyhow::{Context as _, Result};
 use std::fs;
 use std::path::{Path, PathBuf};
 use uuid::Uuid;
@@ -11,7 +11,7 @@ pub fn get_or_create_id(path: &Path) -> Result<String> {
         }
     }
     let new_id = Uuid::new_v4().to_string();
-    fs::create_dir_all(path.parent().ok_or_else(|| anyhow!("invalid id path"))?)?;
+    fs::create_dir_all(path.parent().context("invalid id path")?)?;
     fs::write(path, &new_id)?;
     Ok(new_id)
 }

crates/eval/src/instance.rs

@@ -1,5 +1,5 @@
 use agent::{Message, MessageSegment, SerializedThread, ThreadStore};
-use anyhow::{Context, Result, anyhow, bail};
+use anyhow::{Context as _, Result, anyhow, bail};
 use assistant_tool::ToolWorkingSet;
 use client::proto::LspWorkProgress;
 use futures::channel::mpsc;
@@ -285,7 +285,7 @@ impl ExampleInstance {
 
                 diagnostics_before = query_lsp_diagnostics(project.clone(), cx).await?;
                 if diagnostics_before.is_some() && language_server.allow_preexisting_diagnostics {
-                    return Err(anyhow!("Example has pre-existing diagnostics. If you want to run this example regardless, set `allow_preexisting_diagnostics` to `true` in `base.toml`"));
+                    anyhow::bail!("Example has pre-existing diagnostics. If you want to run this example regardless, set `allow_preexisting_diagnostics` to `true` in `base.toml`");
                 }
 
                 Some(LanguageServerState {
@@ -296,9 +296,7 @@ impl ExampleInstance {
                 None
             };
 
-            if std::env::var("ZED_EVAL_SETUP_ONLY").is_ok() {
-                return Err(anyhow!("Setup only mode"));
-            }
+            anyhow::ensure!(std::env::var("ZED_EVAL_SETUP_ONLY").is_err(), "Setup only mode");
 
             let last_diff_file_path = this.run_directory.join("last.diff");
 
@@ -710,7 +708,7 @@ pub fn wait_for_lang_server(
                 anyhow::Ok(())
             },
             _ = timeout.fuse() => {
-                Err(anyhow!("LSP wait timed out after 5 minutes"))
+                anyhow::bail!("LSP wait timed out after 5 minutes");
             }
         };
         drop(subscriptions);
@@ -808,18 +806,16 @@ pub async fn run_git(repo_path: &Path, args: &[&str]) -> Result<String> {
         .output()
         .await?;
 
-    if output.status.success() {
-        Ok(String::from_utf8(output.stdout)?.trim().to_string())
-    } else {
-        Err(anyhow!(
-            "`git {}` within `{}` failed with status: {}\nstderr:\n{}\nstdout:\n{}",
-            args.join(" "),
-            repo_path.display(),
-            output.status,
-            String::from_utf8_lossy(&output.stderr),
-            String::from_utf8_lossy(&output.stdout),
-        ))
-    }
+    anyhow::ensure!(
+        output.status.success(),
+        "`git {}` within `{}` failed with status: {}\nstderr:\n{}\nstdout:\n{}",
+        args.join(" "),
+        repo_path.display(),
+        output.status,
+        String::from_utf8_lossy(&output.stderr),
+        String::from_utf8_lossy(&output.stdout),
+    );
+    Ok(String::from_utf8(output.stdout)?.trim().to_string())
 }
 
 fn messages_to_markdown<'a>(message_iter: impl IntoIterator<Item = &'a Message>) -> String {
@@ -881,9 +877,7 @@ pub async fn send_language_model_request(
                         full_response.push_str(&chunk_str);
                     }
                     Err(err) => {
-                        return Err(anyhow!(
-                            "Error receiving response from language model: {err}"
-                        ));
+                        anyhow::bail!("Error receiving response from language model: {err}");
                     }
                 }
             }