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/sqlez/src/connection.rs

@@ -6,7 +6,7 @@ use std::{
     ptr,
 };
 
-use anyhow::{Result, anyhow};
+use anyhow::Result;
 use libsqlite3_sys::*;
 
 pub struct Connection {
@@ -199,11 +199,7 @@ impl Connection {
                 )
             };
 
-            Err(anyhow!(
-                "Sqlite call failed with code {} and message: {:?}",
-                code as isize,
-                message
-            ))
+            anyhow::bail!("Sqlite call failed with code {code} and message: {message:?}")
         }
     }
 

crates/sqlez/src/migrations.rs

@@ -6,7 +6,7 @@
 
 use std::ffi::CString;
 
-use anyhow::{Context as _, Result, anyhow};
+use anyhow::{Context as _, Result};
 use indoc::{formatdoc, indoc};
 use libsqlite3_sys::sqlite3_exec;
 
@@ -69,14 +69,14 @@ impl Connection {
                         // Migration already run. Continue
                         continue;
                     } else {
-                        return Err(anyhow!(formatdoc! {"
-                            Migration changed for {} at step {}
+                        anyhow::bail!(formatdoc! {"
+                            Migration changed for {domain} at step {index}
 
                             Stored migration:
-                            {}
+                            {completed_migration}
 
                             Proposed migration:
-                            {}", domain, index, completed_migration, migration}));
+                            {migration}"});
                     }
                 }
 

crates/sqlez/src/savepoint.rs

@@ -78,7 +78,7 @@ mod tests {
 
             assert!(
                 connection
-                    .with_savepoint("second", || -> Result<Option<()>, anyhow::Error> {
+                    .with_savepoint("second", || -> anyhow::Result<Option<()>> {
                         connection.exec_bound("INSERT INTO text(text, idx) VALUES (?, ?)")?((
                             save2_text, 2,
                         ))?;

crates/sqlez/src/statement.rs

@@ -2,7 +2,7 @@ use std::ffi::{CStr, CString, c_int};
 use std::marker::PhantomData;
 use std::{ptr, slice, str};
 
-use anyhow::{Context, Result, anyhow, bail};
+use anyhow::{Context as _, Result, bail};
 use libsqlite3_sys::*;
 
 use crate::bindable::{Bind, Column};
@@ -126,7 +126,7 @@ impl<'a> Statement<'a> {
         if any_succeed {
             Ok(())
         } else {
-            Err(anyhow!("Failed to bind parameters"))
+            anyhow::bail!("Failed to bind parameters")
         }
     }
 
@@ -261,7 +261,7 @@ impl<'a> Statement<'a> {
             SQLITE_TEXT => Ok(SqlType::Text),
             SQLITE_BLOB => Ok(SqlType::Blob),
             SQLITE_NULL => Ok(SqlType::Null),
-            _ => Err(anyhow!("Column type returned was incorrect ")),
+            _ => anyhow::bail!("Column type returned was incorrect"),
         }
     }
 
@@ -282,7 +282,7 @@ impl<'a> Statement<'a> {
                         self.step()
                     }
                 }
-                SQLITE_MISUSE => Err(anyhow!("Statement step returned SQLITE_MISUSE")),
+                SQLITE_MISUSE => anyhow::bail!("Statement step returned SQLITE_MISUSE"),
                 _other_error => {
                     self.connection.last_error()?;
                     unreachable!("Step returned error code and last error failed to catch it");
@@ -328,16 +328,16 @@ impl<'a> Statement<'a> {
             callback: impl FnOnce(&mut Statement) -> Result<R>,
         ) -> Result<R> {
             println!("{:?}", std::any::type_name::<R>());
-            if this.step()? != StepResult::Row {
-                return Err(anyhow!("single called with query that returns no rows."));
-            }
+            anyhow::ensure!(
+                this.step()? == StepResult::Row,
+                "single called with query that returns no rows."
+            );
             let result = callback(this)?;
 
-            if this.step()? != StepResult::Done {
-                return Err(anyhow!(
-                    "single called with a query that returns more than one row."
-                ));
-            }
+            anyhow::ensure!(
+                this.step()? == StepResult::Done,
+                "single called with a query that returns more than one row."
+            );
 
             Ok(result)
         }
@@ -366,11 +366,10 @@ impl<'a> Statement<'a> {
                 .map(|r| Some(r))
                 .context("Failed to parse row result")?;
 
-            if this.step().context("Second step call")? != StepResult::Done {
-                return Err(anyhow!(
-                    "maybe called with a query that returns more than one row."
-                ));
-            }
+            anyhow::ensure!(
+                this.step().context("Second step call")? == StepResult::Done,
+                "maybe called with a query that returns more than one row."
+            );
 
             Ok(result)
         }