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/git/src/blame.rs

@@ -1,6 +1,6 @@
 use crate::commit::get_messages;
 use crate::{GitRemote, Oid};
-use anyhow::{Context as _, Result, anyhow};
+use anyhow::{Context as _, Result};
 use collections::{HashMap, HashSet};
 use futures::AsyncWriteExt;
 use gpui::SharedString;
@@ -80,7 +80,7 @@ async fn run_git_blame(
         .stdout(Stdio::piped())
         .stderr(Stdio::piped())
         .spawn()
-        .map_err(|e| anyhow!("Failed to start git blame process: {}", e))?;
+        .context("starting git blame process")?;
 
     let stdin = child
         .stdin
@@ -92,10 +92,7 @@ async fn run_git_blame(
     }
     stdin.flush().await?;
 
-    let output = child
-        .output()
-        .await
-        .map_err(|e| anyhow!("Failed to read git blame output: {}", e))?;
+    let output = child.output().await.context("reading git blame output")?;
 
     if !output.status.success() {
         let stderr = String::from_utf8_lossy(&output.stderr);
@@ -103,7 +100,7 @@ async fn run_git_blame(
         if trimmed == GIT_BLAME_NO_COMMIT_ERROR || trimmed.contains(GIT_BLAME_NO_PATH) {
             return Ok(String::new());
         }
-        return Err(anyhow!("git blame process failed: {}", stderr));
+        anyhow::bail!("git blame process failed: {stderr}");
     }
 
     Ok(String::from_utf8(output.stdout)?)
@@ -144,21 +141,21 @@ impl BlameEntry {
         let sha = parts
             .next()
             .and_then(|line| line.parse::<Oid>().ok())
-            .ok_or_else(|| anyhow!("failed to parse sha"))?;
+            .context("parsing sha")?;
 
         let original_line_number = parts
             .next()
             .and_then(|line| line.parse::<u32>().ok())
-            .ok_or_else(|| anyhow!("Failed to parse original line number"))?;
+            .context("parsing original line number")?;
         let final_line_number = parts
             .next()
             .and_then(|line| line.parse::<u32>().ok())
-            .ok_or_else(|| anyhow!("Failed to parse final line number"))?;
+            .context("parsing final line number")?;
 
         let line_count = parts
             .next()
             .and_then(|line| line.parse::<u32>().ok())
-            .ok_or_else(|| anyhow!("Failed to parse final line number"))?;
+            .context("parsing line count")?;
 
         let start_line = final_line_number.saturating_sub(1);
         let end_line = start_line + line_count;

crates/git/src/git.rs

@@ -7,7 +7,7 @@ pub mod status;
 
 pub use crate::hosting_provider::*;
 pub use crate::remote::*;
-use anyhow::{Context as _, Result, anyhow};
+use anyhow::{Context as _, Result};
 pub use git2 as libgit;
 use gpui::action_with_deprecated_aliases;
 use gpui::actions;
@@ -99,7 +99,7 @@ impl FromStr for Oid {
 
     fn from_str(s: &str) -> std::prelude::v1::Result<Self, Self::Err> {
         libgit::Oid::from_str(s)
-            .map_err(|error| anyhow!("failed to parse git oid: {}", error))
+            .context("parsing git oid")
             .map(Self)
     }
 }

crates/git/src/repository.rs

@@ -477,7 +477,7 @@ impl GitRepository for RealGitRepository {
                 .stdout(Stdio::piped())
                 .stderr(Stdio::piped())
                 .output()
-                .map_err(|e| anyhow!("Failed to start git show process: {e}"))?;
+                .context("starting git show process")?;
 
             let show_stdout = String::from_utf8_lossy(&show_output.stdout);
             let mut lines = show_stdout.split('\n');
@@ -491,7 +491,7 @@ impl GitRepository for RealGitRepository {
                 .stdout(Stdio::piped())
                 .stderr(Stdio::piped())
                 .spawn()
-                .map_err(|e| anyhow!("Failed to start git cat-file process: {e}"))?;
+                .context("starting git cat-file process")?;
 
             use std::io::Write as _;
             let mut files = Vec::<CommitFile>::new();
@@ -578,12 +578,11 @@ impl GitRepository for RealGitRepository {
                 .args(["reset", mode_flag, &commit])
                 .output()
                 .await?;
-            if !output.status.success() {
-                return Err(anyhow!(
-                    "Failed to reset:\n{}",
-                    String::from_utf8_lossy(&output.stderr)
-                ));
-            }
+            anyhow::ensure!(
+                output.status.success(),
+                "Failed to reset:\n{}",
+                String::from_utf8_lossy(&output.stderr),
+            );
             Ok(())
         }
         .boxed()
@@ -609,12 +608,11 @@ impl GitRepository for RealGitRepository {
                 .args(paths.iter().map(|path| path.as_ref()))
                 .output()
                 .await?;
-            if !output.status.success() {
-                return Err(anyhow!(
-                    "Failed to checkout files:\n{}",
-                    String::from_utf8_lossy(&output.stderr)
-                ));
-            }
+            anyhow::ensure!(
+                output.status.success(),
+                "Failed to checkout files:\n{}",
+                String::from_utf8_lossy(&output.stderr),
+            );
             Ok(())
         }
         .boxed()
@@ -707,12 +705,11 @@ impl GitRepository for RealGitRepository {
                         .output()
                         .await?;
 
-                    if !output.status.success() {
-                        return Err(anyhow!(
-                            "Failed to stage:\n{}",
-                            String::from_utf8_lossy(&output.stderr)
-                        ));
-                    }
+                    anyhow::ensure!(
+                        output.status.success(),
+                        "Failed to stage:\n{}",
+                        String::from_utf8_lossy(&output.stderr)
+                    );
                 } else {
                     let output = new_smol_command(&git_binary_path)
                         .current_dir(&working_directory)
@@ -721,13 +718,11 @@ impl GitRepository for RealGitRepository {
                         .arg(path.to_unix_style())
                         .output()
                         .await?;
-
-                    if !output.status.success() {
-                        return Err(anyhow!(
-                            "Failed to unstage:\n{}",
-                            String::from_utf8_lossy(&output.stderr)
-                        ));
-                    }
+                    anyhow::ensure!(
+                        output.status.success(),
+                        "Failed to unstage:\n{}",
+                        String::from_utf8_lossy(&output.stderr)
+                    );
                 }
 
                 Ok(())
@@ -761,7 +756,7 @@ impl GitRepository for RealGitRepository {
                 let stdin = process
                     .stdin
                     .take()
-                    .ok_or_else(|| anyhow!("no stdin for git cat-file subprocess"))?;
+                    .context("no stdin for git cat-file subprocess")?;
                 let mut stdin = BufWriter::new(stdin);
                 for rev in &revs {
                     write!(&mut stdin, "{rev}\n")?;
@@ -813,7 +808,7 @@ impl GitRepository for RealGitRepository {
                     stdout.parse()
                 } else {
                     let stderr = String::from_utf8_lossy(&output.stderr);
-                    Err(anyhow!("git status failed: {}", stderr))
+                    anyhow::bail!("git status failed: {stderr}");
                 }
             })
             .boxed()
@@ -849,12 +844,11 @@ impl GitRepository for RealGitRepository {
                     .output()
                     .await?;
 
-                if !output.status.success() {
-                    return Err(anyhow!(
-                        "Failed to git git branches:\n{}",
-                        String::from_utf8_lossy(&output.stderr)
-                    ));
-                }
+                anyhow::ensure!(
+                    output.status.success(),
+                    "Failed to git git branches:\n{}",
+                    String::from_utf8_lossy(&output.stderr)
+                );
 
                 let input = String::from_utf8_lossy(&output.stdout);
 
@@ -903,7 +897,7 @@ impl GitRepository for RealGitRepository {
                     branch.set_upstream(Some(&name))?;
                     branch
                 } else {
-                    return Err(anyhow!("Branch not found"));
+                    anyhow::bail!("Branch not found");
                 };
 
                 let revision = branch.get();
@@ -912,7 +906,7 @@ impl GitRepository for RealGitRepository {
                 repo.set_head(
                     revision
                         .name()
-                        .ok_or_else(|| anyhow!("Branch name could not be retrieved"))?,
+                        .context("Branch name could not be retrieved")?,
                 )?;
                 Ok(())
             })
@@ -970,12 +964,11 @@ impl GitRepository for RealGitRepository {
                     .output()
                     .await?;
 
-                if !output.status.success() {
-                    return Err(anyhow!(
-                        "Failed to run git diff:\n{}",
-                        String::from_utf8_lossy(&output.stderr)
-                    ));
-                }
+                anyhow::ensure!(
+                    output.status.success(),
+                    "Failed to run git diff:\n{}",
+                    String::from_utf8_lossy(&output.stderr)
+                );
                 Ok(String::from_utf8_lossy(&output.stdout).to_string())
             })
             .boxed()
@@ -998,13 +991,11 @@ impl GitRepository for RealGitRepository {
                         .args(paths.iter().map(|p| p.to_unix_style()))
                         .output()
                         .await?;
-
-                    if !output.status.success() {
-                        return Err(anyhow!(
-                            "Failed to stage paths:\n{}",
-                            String::from_utf8_lossy(&output.stderr)
-                        ));
-                    }
+                    anyhow::ensure!(
+                        output.status.success(),
+                        "Failed to stage paths:\n{}",
+                        String::from_utf8_lossy(&output.stderr),
+                    );
                 }
                 Ok(())
             })
@@ -1030,12 +1021,11 @@ impl GitRepository for RealGitRepository {
                         .output()
                         .await?;
 
-                    if !output.status.success() {
-                        return Err(anyhow!(
-                            "Failed to unstage:\n{}",
-                            String::from_utf8_lossy(&output.stderr)
-                        ));
-                    }
+                    anyhow::ensure!(
+                        output.status.success(),
+                        "Failed to unstage:\n{}",
+                        String::from_utf8_lossy(&output.stderr),
+                    );
                 }
                 Ok(())
             })
@@ -1069,12 +1059,11 @@ impl GitRepository for RealGitRepository {
 
                 let output = cmd.output().await?;
 
-                if !output.status.success() {
-                    return Err(anyhow!(
-                        "Failed to commit:\n{}",
-                        String::from_utf8_lossy(&output.stderr)
-                    ));
-                }
+                anyhow::ensure!(
+                    output.status.success(),
+                    "Failed to commit:\n{}",
+                    String::from_utf8_lossy(&output.stderr)
+                );
                 Ok(())
             })
             .boxed()
@@ -1190,22 +1179,19 @@ impl GitRepository for RealGitRepository {
                     .output()
                     .await?;
 
-                if output.status.success() {
-                    let remote_names = String::from_utf8_lossy(&output.stdout)
-                        .split('\n')
-                        .filter(|name| !name.is_empty())
-                        .map(|name| Remote {
-                            name: name.trim().to_string().into(),
-                        })
-                        .collect();
-
-                    return Ok(remote_names);
-                } else {
-                    return Err(anyhow!(
-                        "Failed to get remotes:\n{}",
-                        String::from_utf8_lossy(&output.stderr)
-                    ));
-                }
+                anyhow::ensure!(
+                    output.status.success(),
+                    "Failed to get remotes:\n{}",
+                    String::from_utf8_lossy(&output.stderr)
+                );
+                let remote_names = String::from_utf8_lossy(&output.stdout)
+                    .split('\n')
+                    .filter(|name| !name.is_empty())
+                    .map(|name| Remote {
+                        name: name.trim().to_string().into(),
+                    })
+                    .collect();
+                Ok(remote_names)
             })
             .boxed()
     }
@@ -1222,11 +1208,11 @@ impl GitRepository for RealGitRepository {
                         .args(args)
                         .output()
                         .await?;
-                    if output.status.success() {
-                        Ok(String::from_utf8(output.stdout)?)
-                    } else {
-                        Err(anyhow!(String::from_utf8_lossy(&output.stderr).to_string()))
-                    }
+                    anyhow::ensure!(
+                        output.status.success(),
+                        String::from_utf8_lossy(&output.stderr).to_string()
+                    );
+                    Ok(String::from_utf8(output.stdout)?)
                 };
 
                 let head = git_cmd(&["rev-parse", "HEAD"])
@@ -1504,14 +1490,14 @@ impl GitBinary {
     {
         let mut command = self.build_command(args);
         let output = command.output().await?;
-        if output.status.success() {
-            Ok(String::from_utf8(output.stdout)?)
-        } else {
-            Err(anyhow!(GitBinaryCommandError {
+        anyhow::ensure!(
+            output.status.success(),
+            GitBinaryCommandError {
                 stdout: String::from_utf8_lossy(&output.stdout).to_string(),
                 status: output.status,
-            }))
-        }
+            }
+        );
+        Ok(String::from_utf8(output.stdout)?)
     }
 
     fn build_command<S>(&self, args: impl IntoIterator<Item = S>) -> smol::process::Command
@@ -1545,14 +1531,15 @@ async fn run_git_command(
     if env.contains_key("GIT_ASKPASS") {
         let git_process = command.spawn()?;
         let output = git_process.output().await?;
-        if !output.status.success() {
-            Err(anyhow!("{}", String::from_utf8_lossy(&output.stderr)))
-        } else {
-            Ok(RemoteCommandOutput {
-                stdout: String::from_utf8_lossy(&output.stdout).to_string(),
-                stderr: String::from_utf8_lossy(&output.stderr).to_string(),
-            })
-        }
+        anyhow::ensure!(
+            output.status.success(),
+            "{}",
+            String::from_utf8_lossy(&output.stderr)
+        );
+        Ok(RemoteCommandOutput {
+            stdout: String::from_utf8_lossy(&output.stdout).to_string(),
+            stderr: String::from_utf8_lossy(&output.stderr).to_string(),
+        })
     } else {
         let ask_pass = AskPassSession::new(executor, ask_pass).await?;
         command
@@ -1568,7 +1555,7 @@ async fn run_git_command(
 async fn run_askpass_command(
     mut ask_pass: AskPassSession,
     git_process: smol::process::Child,
-) -> std::result::Result<RemoteCommandOutput, anyhow::Error> {
+) -> anyhow::Result<RemoteCommandOutput> {
     select_biased! {
         result = ask_pass.run().fuse() => {
             match result {
@@ -1582,17 +1569,15 @@ async fn run_askpass_command(
         }
         output = git_process.output().fuse() => {
             let output = output?;
-            if !output.status.success() {
-                Err(anyhow!(
-                    "{}",
-                    String::from_utf8_lossy(&output.stderr)
-                ))
-            } else {
-                Ok(RemoteCommandOutput {
-                    stdout: String::from_utf8_lossy(&output.stdout).to_string(),
-                    stderr: String::from_utf8_lossy(&output.stderr).to_string(),
-                })
-            }
+            anyhow::ensure!(
+                output.status.success(),
+                "{}",
+                String::from_utf8_lossy(&output.stderr)
+            );
+            Ok(RemoteCommandOutput {
+                stdout: String::from_utf8_lossy(&output.stdout).to_string(),
+                stderr: String::from_utf8_lossy(&output.stderr).to_string(),
+            })
         }
     }
 }
@@ -1752,12 +1737,8 @@ fn parse_upstream_track(upstream_track: &str) -> Result<UpstreamTracking> {
         }));
     }
 
-    let upstream_track = upstream_track
-        .strip_prefix("[")
-        .ok_or_else(|| anyhow!("missing ["))?;
-    let upstream_track = upstream_track
-        .strip_suffix("]")
-        .ok_or_else(|| anyhow!("missing ["))?;
+    let upstream_track = upstream_track.strip_prefix("[").context("missing [")?;
+    let upstream_track = upstream_track.strip_suffix("]").context("missing [")?;
     let mut ahead: u32 = 0;
     let mut behind: u32 = 0;
     for component in upstream_track.split(", ") {

crates/git/src/status.rs

@@ -1,5 +1,5 @@
 use crate::repository::RepoPath;
-use anyhow::{Result, anyhow};
+use anyhow::Result;
 use serde::{Deserialize, Serialize};
 use std::{path::Path, str::FromStr, sync::Arc};
 use util::ResultExt;
@@ -241,7 +241,7 @@ impl StatusCode {
             b'R' => Ok(StatusCode::Renamed),
             b'C' => Ok(StatusCode::Copied),
             b' ' => Ok(StatusCode::Unmodified),
-            _ => Err(anyhow!("Invalid status code: {byte}")),
+            _ => anyhow::bail!("Invalid status code: {byte}"),
         }
     }
 
@@ -286,7 +286,7 @@ impl UnmergedStatusCode {
             b'A' => Ok(UnmergedStatusCode::Added),
             b'D' => Ok(UnmergedStatusCode::Deleted),
             b'U' => Ok(UnmergedStatusCode::Updated),
-            _ => Err(anyhow!("Invalid unmerged status code: {byte}")),
+            _ => anyhow::bail!("Invalid unmerged status code: {byte}"),
         }
     }
 }