feat: improve error handling with contextual error messages

Mubashwer · Mubashwer · commit c0cc51091a9c · 2025-07-17T02:28:20.000+10:00
- Migrate from Box&lt;dyn Error&gt; to anyhow for better error handling
- Add contextual error messages throughout the codebase using anyhow::Context
- Use bail! macro for cleaner error creation
- Provide more helpful error messages for git command failures
- Add specific context for team member and mob session operations
- Update test expectations to match new error message format

Users now get more informative error messages with context about what operation failed and why.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -23,6 +23,7 @@ name = "git-mob"
 path = "src/main.rs"
 
 [dependencies]
+anyhow = "1.0"
 clap = { version = "4.5.39", features = ["derive"] }
 inquire = "0.7.5"
 path-clean = "1.0.1"
diff --git a/src/commands/mob.rs b/src/commands/mob.rs
@@ -1,5 +1,6 @@
 use crate::Result;
 use crate::repositories::{MobSessionRepo, TeamMemberRepo};
+use anyhow::bail;
 use clap::{Parser, arg};
 use inquire::MultiSelect;
 use std::io::Write;
@@ -72,9 +73,7 @@ impl Mob {
             Some([]) => {
                 let team_members = team_member_repo.list(false)?;
                 if team_members.is_empty() {
-                    return Err(
-                        "No team member(s) found. At least one team member must be added".into(),
-                    );
+                    bail!("No team member(s) found. At least one team member must be added");
                 }
 
                 let result = MultiSelect::new("Select active co-author(s):", team_members)
@@ -100,7 +99,7 @@ impl Mob {
                             mob_repo.add_coauthor(&team_member)?;
                             coauthors.push(team_member);
                         }
-                        None => return Err(format!("No team member found with key: {key}").into()),
+                        None => bail!("No team member found with key: {key}"),
                     }
                 }
 
diff --git a/src/commands/setup.rs b/src/commands/setup.rs
@@ -1,4 +1,5 @@
 use crate::Result;
+use anyhow::bail;
 use clap::Parser;
 use path_clean::PathClean;
 use std::{
@@ -40,11 +41,10 @@ impl Setup {
         let hooks_dir = match Self::get_hooks_dir("--global")? {
             Some(hooks_dir) => hooks_dir,
             None => {
-                let new_hooks_dir = env::home_dir()
-                    .ok_or("Failed to get home directory")?
-                    .join(".git")
-                    .join("hooks")
-                    .clean();
+                let Some(home_dir) = env::home_dir() else {
+                    bail!("Failed to get home directory");
+                };
+                let new_hooks_dir = home_dir.join(".git").join("hooks").clean();
 
                 Self::set_global_hooks_dir(out, &new_hooks_dir)?;
 
@@ -73,7 +73,7 @@ impl Setup {
     fn handle_local(&self, out: &mut impl Write) -> Result<()> {
         let hooks_dir = match Self::get_hooks_dir("--local")? {
             Some(hooks_dir) => hooks_dir,
-            None => return Err("Local githooks directory is not set".into()),
+            None => bail!("Local githooks directory is not set"),
         };
 
         let prepare_commit_msg_path = hooks_dir.join("prepare-commit-msg").clean();
@@ -108,7 +108,9 @@ impl Setup {
             return Ok(Some(hooks_dir));
         }
 
-        let mut expanded_hooks_dir = env::home_dir().ok_or("Failed to get home directory")?;
+        let Some(mut expanded_hooks_dir) = env::home_dir() else {
+            bail!("Failed to get home directory");
+        };
         expanded_hooks_dir.extend(hooks_dir.components().skip(1));
         Ok(Some(expanded_hooks_dir.clean()))
     }
@@ -120,7 +122,7 @@ impl Setup {
             .status()?;
 
         if !status.success() {
-            return Err(format!("Failed to set global githooks directory to {path_str}").into());
+            bail!("Failed to set global githooks directory to {path_str}");
         }
 
         writeln!(out, "Set global githooks directory: {path_str}")?;
diff --git a/src/commands/team_member.rs b/src/commands/team_member.rs
@@ -1,5 +1,6 @@
 use crate::Result;
 use crate::repositories::TeamMemberRepo;
+use anyhow::bail;
 use clap::{Parser, arg};
 use std::io::Write;
 
@@ -32,7 +33,7 @@ impl TeamMember {
         if let Some(key) = self.delete.as_deref() {
             match team_member_repo.get(key)? {
                 Some(_) => team_member_repo.remove(key)?,
-                None => return Err(format!("No team member found with key: {key}").into()),
+                None => bail!("No team member found with key: {key}"),
             }
         }
         if self.list {
diff --git a/src/helpers.rs b/src/helpers.rs
@@ -1,4 +1,5 @@
 use crate::Result;
+use anyhow::Context;
 use std::process::Command;
 
 pub struct CmdOutput {
@@ -19,7 +20,9 @@ pub struct StdCommandRunner;
 
 impl CommandRunner for StdCommandRunner {
     fn execute(&self, program: &str, args: &[&str]) -> Result<CmdOutput> {
-        let output = Command::new(program).args(args).output()?;
+        let output = Command::new(program).args(args).output().with_context(|| {
+            format!("Failed to execute command: {} {}", program, args.join(" "))
+        })?;
 
         Ok(CmdOutput {
             stdout: output.stdout,
diff --git a/src/lib.rs b/src/lib.rs
@@ -1,4 +1,4 @@
-pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
+pub type Result<T> = anyhow::Result<T>;
 
 pub mod cli;
 mod commands;
diff --git a/src/repositories/mob_session_repo.rs b/src/repositories/mob_session_repo.rs
@@ -1,5 +1,6 @@
 use crate::Result;
 use crate::helpers::{CmdOutput, CommandRunner};
+use anyhow::{Context, bail};
 
 #[cfg(test)]
 use mockall::{automock, predicate::*};
@@ -23,8 +24,8 @@ impl<Cmd: CommandRunner> GitConfigMobRepo<Cmd> {
 
     fn git_config_error<T>(output: &CmdOutput) -> Result<T> {
         match output.status_code {
-            Some(code) => Err(format!("Git config command exited with status code: {code}").into()),
-            None => Err("Git config command terminated by signal".into()),
+            Some(code) => bail!("Git config command exited with status code: {code}"),
+            None => bail!("Git config command terminated by signal"),
         }
     }
 }
@@ -35,10 +36,12 @@ impl<Cmd: CommandRunner> MobSessionRepo for GitConfigMobRepo<Cmd> {
 
         let output = self
             .command_runner
-            .execute("git", &["config", "--global", "--get-all", &full_key])?;
+            .execute("git", &["config", "--global", "--get-all", &full_key])
+            .context("Failed to list coauthors from git config")?;
 
         match output.status_code {
-            Some(Self::EXIT_CODE_SUCCESS) => Ok(String::from_utf8(output.stdout)?
+            Some(Self::EXIT_CODE_SUCCESS) => Ok(String::from_utf8(output.stdout)
+                .context("Failed to parse git config output as UTF-8")?
                 .lines()
                 .map(|x| x.into())
                 .collect()),
@@ -52,7 +55,8 @@ impl<Cmd: CommandRunner> MobSessionRepo for GitConfigMobRepo<Cmd> {
 
         let output = self
             .command_runner
-            .execute("git", &["config", "--global", "--add", &full_key, coauthor])?;
+            .execute("git", &["config", "--global", "--add", &full_key, coauthor])
+            .with_context(|| format!("Failed to add coauthor '{coauthor}' to git config"))?;
 
         match output.status_code {
             Some(Self::EXIT_CODE_SUCCESS) => Ok(()),
@@ -68,7 +72,8 @@ impl<Cmd: CommandRunner> MobSessionRepo for GitConfigMobRepo<Cmd> {
 
         let output = self
             .command_runner
-            .execute("git", &["config", "--global", "--remove-section", &section])?;
+            .execute("git", &["config", "--global", "--remove-section", &section])
+            .context("Failed to clear mob session from git config")?;
 
         match output.status_code {
             Some(Self::EXIT_CODE_SUCCESS) => Ok(()),
diff --git a/src/repositories/team_member_repo.rs b/src/repositories/team_member_repo.rs
@@ -1,5 +1,6 @@
 use crate::Result;
 use crate::helpers::{CmdOutput, CommandRunner};
+use anyhow::{Context, bail};
 
 #[cfg(test)]
 use mockall::{automock, predicate::*};
@@ -24,8 +25,8 @@ impl<Cmd: CommandRunner> GitConfigTeamMemberRepo<Cmd> {
 
     fn git_config_error<T>(output: &CmdOutput) -> Result<T> {
         match output.status_code {
-            Some(code) => Err(format!("Git config command exited with status code: {code}").into()),
-            None => Err("Git config command terminated by signal".into()),
+            Some(code) => bail!("Git config command exited with status code: {code}"),
+            None => bail!("Git config command terminated by signal"),
         }
     }
 }
@@ -35,23 +36,28 @@ impl<Cmd: CommandRunner> TeamMemberRepo for GitConfigTeamMemberRepo<Cmd> {
         let section = Self::COAUTHORS_SECTION;
         let search_regex = format!("^{section}\\.");
 
-        let output = self.command_runner.execute(
-            "git",
-            &["config", "--global", "--get-regexp", &search_regex],
-        )?;
+        let output = self
+            .command_runner
+            .execute(
+                "git",
+                &["config", "--global", "--get-regexp", &search_regex],
+            )
+            .context("Failed to list team members from git config")?;
 
         match output.status_code {
-            Some(Self::EXIT_CODE_SUCCESS) => String::from_utf8(output.stdout)?
+            Some(Self::EXIT_CODE_SUCCESS) => String::from_utf8(output.stdout)
+                .context("Failed to parse git config output as UTF-8")?
                 .lines()
                 .map(|x| {
                     let delimiter = if show_keys {
                         format!("{section}.")
                     } else {
                         " ".to_owned()
                     };
-                    x.split_once(&delimiter)
-                        .ok_or(format!("Failed to split string: '{x}'").into())
-                        .map(|(_, team_member)| team_member.to_owned())
+                    let Some((_, team_member)) = x.split_once(&delimiter) else {
+                        bail!("Failed to split git config line: '{x}'");
+                    };
+                    Ok(team_member.to_owned())
                 })
                 .collect(),
 
@@ -65,12 +71,16 @@ impl<Cmd: CommandRunner> TeamMemberRepo for GitConfigTeamMemberRepo<Cmd> {
 
         let output = self
             .command_runner
-            .execute("git", &["config", "--global", &full_key])?;
+            .execute("git", &["config", "--global", &full_key])
+            .with_context(|| format!("Failed to get team member '{key}' from git config"))?;
 
         match output.status_code {
-            Some(Self::EXIT_CODE_SUCCESS) => {
-                Ok(Some(String::from_utf8(output.stdout)?.trim().into()))
-            }
+            Some(Self::EXIT_CODE_SUCCESS) => Ok(Some(
+                String::from_utf8(output.stdout)
+                    .context("Failed to parse git config output as UTF-8")?
+                    .trim()
+                    .into(),
+            )),
             Some(Self::EXIT_CODE_CONFIG_INVALID_KEY) => Ok(None),
             _ => Self::git_config_error(&output),
         }
@@ -81,7 +91,8 @@ impl<Cmd: CommandRunner> TeamMemberRepo for GitConfigTeamMemberRepo<Cmd> {
 
         let output = self
             .command_runner
-            .execute("git", &["config", "--global", "--unset-all", &full_key])?;
+            .execute("git", &["config", "--global", "--unset-all", &full_key])
+            .with_context(|| format!("Failed to remove team member '{key}' from git config"))?;
 
         match output.status_code {
             Some(Self::EXIT_CODE_SUCCESS) => Ok(()),
@@ -94,11 +105,14 @@ impl<Cmd: CommandRunner> TeamMemberRepo for GitConfigTeamMemberRepo<Cmd> {
 
         let output = self
             .command_runner
-            .execute("git", &["config", "--global", &full_key, team_member])?;
+            .execute("git", &["config", "--global", &full_key, team_member])
+            .with_context(|| format!("Failed to add team member '{key}' to git config"))?;
 
         match output.status_code {
             Some(Self::EXIT_CODE_SUCCESS) => Ok(()),
-            Some(Self::EXIT_CODE_CONFIG_INVALID_KEY) => Err(format!("Invalid key: {key}").into()),
+            Some(Self::EXIT_CODE_CONFIG_INVALID_KEY) => {
+                bail!("Invalid key: {key}")
+            }
             _ => Self::git_config_error(&output),
         }
     }
diff --git a/tests/mob.rs b/tests/mob.rs
@@ -44,7 +44,7 @@ fn test_mob_with_by_key_when_team_member_not_found(
         .assert()
         .failure()
         .stderr(predicate::str::diff(
-            "Error: \"No team member found with key: jk\"\n",
+            "Error: No team member found with key: jk\n",
         ));
 
     Ok(())
@@ -61,7 +61,7 @@ fn test_mob_with_multiselect_given_no_team_members_added(
         .assert()
         .failure()
         .stderr(predicate::str::diff(
-            "Error: \"No team member(s) found. At least one team member must be added\"\n",
+            "Error: No team member(s) found. At least one team member must be added\n",
         ));
 
     Ok(())
diff --git a/tests/setup.rs b/tests/setup.rs
@@ -190,7 +190,7 @@ fn test_setup_given_invalid_git_config_global_path(
         .assert()
         .failure()
         .stderr(predicate::str::contains(
-            "Error: \"Failed to set global githooks directory to",
+            "Error: Failed to set global githooks directory to",
         ));
 
     Ok(())
@@ -203,7 +203,7 @@ fn test_setup_local_given_hooks_dir_not_set(ctx: TestContextRepo) -> Result<(),
         .args(["mob", "setup", "--local"])
         .assert()
         .failure()
-        .stderr("Error: \"Local githooks directory is not set\"\n");
+        .stderr("Error: Local githooks directory is not set\n");
 
     Ok(())
 }
diff --git a/tests/team_member.rs b/tests/team_member.rs
@@ -65,7 +65,7 @@ fn test_add_member_with_invalid_key(ctx: TestContextCli) -> Result<(), Box<dyn E
         .assert()
         .failure()
         .stderr(predicate::str::diff(
-            "Error: \"Invalid key: invalid_key_with_underscore\"\n",
+            "Error: Invalid key: invalid_key_with_underscore\n",
         ));
 
     Ok(())
@@ -139,7 +139,7 @@ fn test_delete_member_when_member_not_found(ctx: TestContextCli) -> Result<(), B
         .assert()
         .failure()
         .stderr(predicate::str::diff(
-            "Error: \"No team member found with key: lm\"\n",
+            "Error: No team member found with key: lm\n",
         ));
 
     Ok(())

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,6 @@`
`1`	`1`	`use crate::Result;`
`2`	`2`	`use crate::repositories::{MobSessionRepo, TeamMemberRepo};`
	`3`	`+use anyhow::bail;`
`3`	`4`	`use clap::{Parser, arg};`
`4`	`5`	`use inquire::MultiSelect;`
`5`	`6`	`use std::io::Write;`
`@@ -72,9 +73,7 @@ impl Mob {`
`72`	`73`	`Some([]) => {`
`73`	`74`	`let team_members = team_member_repo.list(false)?;`
`74`	`75`	`if team_members.is_empty() {`
`75`		`- return Err(`
`76`		`- "No team member(s) found. At least one team member must be added".into(),`
`77`		`- );`
	`76`	`+ bail!("No team member(s) found. At least one team member must be added");`
`78`	`77`	`}`
`79`	`78`
`80`	`79`	`let result = MultiSelect::new("Select active co-author(s):", team_members)`
`@@ -100,7 +99,7 @@ impl Mob {`
`100`	`99`	`mob_repo.add_coauthor(&team_member)?;`
`101`	`100`	`coauthors.push(team_member);`
`102`	`101`	`}`
`103`		`- None => return Err(format!("No team member found with key: {key}").into()),`
	`102`	`+ None => bail!("No team member found with key: {key}"),`
`104`	`103`	`}`
`105`	`104`	`}`
`106`	`105`
Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,6 @@`
`1`	`1`	`use crate::Result;`
`2`	`2`	`use crate::repositories::TeamMemberRepo;`
	`3`	`+use anyhow::bail;`
`3`	`4`	`use clap::{Parser, arg};`
`4`	`5`	`use std::io::Write;`
`5`	`6`
`@@ -32,7 +33,7 @@ impl TeamMember {`
`32`	`33`	`if let Some(key) = self.delete.as_deref() {`
`33`	`34`	`match team_member_repo.get(key)? {`
`34`	`35`	`Some(_) => team_member_repo.remove(key)?,`
`35`		`- None => return Err(format!("No team member found with key: {key}").into()),`
	`36`	`+ None => bail!("No team member found with key: {key}"),`
`36`	`37`	`}`
`37`	`38`	`}`
`38`	`39`	`if self.list {`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;`
	`1`	`+pub type Result<T> = anyhow::Result<T>;`
`2`	`2`
`3`	`3`	`pub mod cli;`
`4`	`4`	`mod commands;`