Improve error reporting

src/decman/__init__.py

@@ -23,33 +23,35 @@ def sh(sh_cmd: str,
     env = os.environ.copy()
     for var, val in env_overrides.items():
         env[var] = val
-    try:
 
     if user is None:
+        try:
             subprocess.run(sh_cmd, shell=True, check=True, env=env)
+        except subprocess.CalledProcessError as e:
+            raise decman.error.UserFacingError(
+                f"Running user defined shell command '{sh_cmd}' failed."
+            ) from e
     else:
+        try:
             uid = pwd.getpwnam(user).pw_uid
             gid = pwd.getpwnam(user).pw_gid
+        except KeyError as e:
+            raise decman.error.UserFacingError(
+                f"Running user defined shell command failed because the user {user} doesn't exist."
+            ) from e
 
-            with subprocess.Popen(sh_cmd,
+        with subprocess.Popen(sh_cmd, shell=True, group=gid, user=uid,
-                                  shell=True,
-                                  group=gid,
-                                  user=uid,
                               env=env) as process:
             if process.wait() != 0:
                 raise decman.error.UserFacingError(
-                        f"Running user shell command '{sh_cmd}' as {user} failed."
+                    f"Running user shell command '{sh_cmd}' as {user} failed.")
-                    )
-    except (subprocess.CalledProcessError, KeyError) as e:
-        raise decman.error.UserFacingError(
-            f"Running user shell command '{sh_cmd}' failed.") from e
 
 
-def cmd(command: list[str],
+def prg(command: list[str],
         user: typing.Optional[str] = None,
         env_overrides: typing.Optional[dict[str, str]] = None):
     """
-    Shortcut for running a command.
+    Shortcut for running a program.
     """
     if env_overrides is None:
         env_overrides = {}
@@ -58,21 +60,26 @@ def cmd(command: list[str],
     for var, val in env_overrides.items():
         env[var] = val
 
-    try:
     if user is None:
+        try:
             subprocess.run(command, check=True, env=env)
+        except subprocess.CalledProcessError as e:
+            raise decman.error.UserFacingError(
+                f"Running user defined program '{command}' failed.") from e
     else:
+        try:
             uid = pwd.getpwnam(user).pw_uid
             gid = pwd.getpwnam(user).pw_gid
+        except KeyError as e:
+            raise decman.error.UserFacingError(
+                f"Running user defined program failed because the user {user} doesn't exist."
+            ) from e
 
         with subprocess.Popen(command, group=gid, user=uid,
                               env=env) as process:
             if process.wait() != 0:
                 raise decman.error.UserFacingError(
-                        f"Running user command '{command}' as {user} failed.")
+                    f"Running user program '{command}' as {user} failed.")
-    except (subprocess.CalledProcessError, KeyError) as e:
-        raise decman.error.UserFacingError(
-            f"Running user command '{command}' failed.") from e
 
 
 class File:

src/decman/lib/__init__.py

@@ -182,7 +182,8 @@ class Store:
             with open(path, "wt", encoding="utf-8") as file:
                 json.dump(d, file)
         except OSError as e:
-            raise err.UserFacingError("Failed to save store.") from e
+            print_error(f"{e}")
+            raise err.UserFacingError("Failed to save decman store.") from e
 
     @staticmethod
     def restore() -> "Store":
@@ -220,9 +221,13 @@ class Store:
 
             return store
         except json.JSONDecodeError as e:
-            raise err.UserFacingError("Failed to parse state json.") from e
+            print_error(f"{e}")
+            raise err.UserFacingError(
+                "Failed to parse decman store json.") from e
         except OSError as e:
-            raise err.UserFacingError("Failed to read saved store.") from e
+            print_error(f"{e}")
+            raise err.UserFacingError(
+                "Failed to read saved decman store.") from e
 
 
 class Source:
@@ -302,6 +307,7 @@ class Source:
                     file.copy_to(target, variables)
                     print_debug(f"Installing file to {target}.")
                 except OSError as e:
+                    print_error(f"{e}")
                     raise err.UserFacingError(
                         f"Failed to install file to {target}.") from e
 
@@ -312,6 +318,7 @@ class Source:
                     print_debug(f"Installing directory to {target}.")
                     directory.copy_to(target, variables)
                 except OSError as e:
+                    print_error(f"{e}")
                     raise err.UserFacingError(
                         f"Failed to install directory to {target}.") from e
 
@@ -543,7 +550,7 @@ class Pacman:
                     for line in output]
         except IndexError as error:
             raise err.UserFacingError(
-                f"Failed to get foreign packages from pacman output. Output: {output}"
+                f"Failed to parse foreign packages from pacman output. Output: {output}"
             ) from error
 
     def install(self, packages: list[str]):
@@ -553,7 +560,8 @@ class Pacman:
         try:
             subprocess.run(conf.commands.install_pkgs(packages), check=True)
         except subprocess.CalledProcessError as error:
-            raise err.UserFacingError("Failed to install packages.") from error
+            raise err.UserFacingError(
+                "Failed to install packages using pacman.") from error
 
     def install_dependencies(self, deps: list[str]):
         """
@@ -563,7 +571,8 @@ class Pacman:
             subprocess.run(conf.commands.install_deps(deps), check=True)
         except subprocess.CalledProcessError as error:
             raise err.UserFacingError(
-                "Failed to install dependency packages.") from error
+                "Failed to install packages as dependencies using pacman."
+            ) from error
 
     def install_files(self, files: list[str], as_explicit: list[str]):
         """
@@ -577,8 +586,11 @@ class Pacman:
                 check=True,
                 capture_output=conf.suppress_command_output)
         except subprocess.CalledProcessError as error:
+            if conf.suppress_command_output:
+                print_error("Output:")
+                print_continuation(error.output)
             raise err.UserFacingError(
-                "Failed to install foreign packages.") from error
+                "Failed to install package files using pacman.") from error
 
     def upgrade(self):
         """
@@ -587,7 +599,8 @@ class Pacman:
         try:
             subprocess.run(conf.commands.upgrade(), check=True)
         except subprocess.CalledProcessError as error:
-            raise err.UserFacingError("Failed to update packages.") from error
+            raise err.UserFacingError(
+                "Failed to upgrade packages using pacman.") from error
 
     def remove(self, packages: list[str]):
         """
@@ -596,7 +609,8 @@ class Pacman:
         try:
             subprocess.run(conf.commands.remove(packages), check=True)
         except subprocess.CalledProcessError as error:
-            raise err.UserFacingError("Failed to remove packages.") from error
+            raise err.UserFacingError(
+                "Failed to remove packages using pacman.") from error
 
 
 class Systemd:
@@ -615,7 +629,7 @@ class Systemd:
             subprocess.run(conf.commands.enable_units(units), check=True)
         except subprocess.CalledProcessError as error:
             raise err.UserFacingError(
-                "Failed to enable systemd units.") from error
+                f"Failed to enable systemd units: {units}") from error
         self.state.enabled_systemd_units += units
 
     def disable_units(self, units: list[str]):
@@ -626,7 +640,7 @@ class Systemd:
             subprocess.run(conf.commands.disable_units(units), check=True)
         except subprocess.CalledProcessError as error:
             raise err.UserFacingError(
-                "Failed to disable systemd units.") from error
+                f"Failed to disable systemd units: {units}") from error
         for unit in units:
             try:
                 self.state.enabled_systemd_units.remove(unit)
@@ -646,10 +660,10 @@ class Systemd:
                                   user=uid) as process:
                 if process.wait() != 0:
                     raise err.UserFacingError(
-                        f"Failed to enable systemd units for {user}.")
+                        f"Failed to enable systemd units: {units} for {user}.")
         except KeyError as error:
             raise err.UserFacingError(
-                f"Failed to enable systemd units because user '{user}' doesn't exist."
+                f"Failed to enable systemd units because user {user} doesn't exist."
             ) from error
         for unit in units:
             self.state.enabled_user_systemd_units.append((user, unit))
@@ -667,10 +681,11 @@ class Systemd:
                                   user=uid) as process:
                 if process.wait() != 0:
                     raise err.UserFacingError(
-                        f"Failed to disable systemd units for {user}.")
+                        f"Failed to disable systemd units: {units} for {user}."
+                    )
         except KeyError as error:
             raise err.UserFacingError(
-                f"Failed to disable systemd units because user '{user}' doesn't exist."
+                f"Failed to disable systemd units because user {user} doesn't exist."
             ) from error
 
         for unit in units:

src/decman/lib/aur.py

@@ -324,8 +324,10 @@ class ExtendedPackageSearch:
 
                 l.print_debug("Request completed.")
             except (requests.RequestException, KeyError) as e:
+                l.print_error(f"{e}")
                 raise err.UserFacingError(
-                    "Failed to fetch package information from AUR RPC.") from e
+                    f"Failed to fetch package information for {packages} from AUR RPC."
+                ) from e
 
     def get_package_info(self, package: str) -> typing.Optional[PackageInfo]:
         """
@@ -379,8 +381,10 @@ class ExtendedPackageSearch:
 
             return info
         except (requests.RequestException, KeyError) as e:
+            l.print_error(f"{e}")
             raise err.UserFacingError(
-                "Failed to fetch package information from AUR RPC.") from e
+                f"Failed to fetch package information for {package} from AUR RPC."
+            ) from e
 
     def find_provider(
             self, stripped_dependency: str) -> typing.Optional[PackageInfo]:
@@ -452,8 +456,10 @@ class ExtendedPackageSearch:
 
             return self._choose_provider(stripped_dependency, results, "AUR")
         except (requests.RequestException, KeyError) as e:
+            l.print_error(f"{e}")
             raise err.UserFacingError(
-                "Failed to fetch package information from AUR RPC.") from e
+                f"Failed to search for {stripped_dependency} from AUR RPC."
+            ) from e
 
     def _choose_provider(self, dep: str, possible_providers: list[str],
                          where: str) -> typing.Optional[PackageInfo]:
@@ -569,7 +575,9 @@ class ForeignPackageManager:
 
             info = self._search.get_package_info(pkg)
             if info is None:
-                raise err.UserFacingError(f"Failed to find package: {pkg}.")
+                raise err.UserFacingError(
+                    f"Failed to find '{pkg}' from AUR or user provided packages."
+                )
 
             if self.should_upgrade_package(pkg, ver, info.version,
                                            upgrade_devel):
@@ -650,6 +658,7 @@ class ForeignPackageManager:
 
                     builder.build_packages(pkgbase, packages, force)
         except (subprocess.CalledProcessError, OSError) as e:
+            l.print_error(f"{e}")
             raise err.UserFacingError("Failed to build packages.") from e
 
         packages_to_install = list(resolved_dependencies.foreign_pkgs)
@@ -792,7 +801,9 @@ class ForeignPackageManager:
             )
             return should_upgrade
         except (ValueError, subprocess.CalledProcessError) as error:
-            raise err.UserFacingError("Failed to compare versions.") from error
+            l.print_error(f"{error}")
+            raise err.UserFacingError(
+                "Failed to compare versions using vercmp.") from error
 
 
 class PackageBuilder:
@@ -1058,7 +1069,7 @@ class PackageBuilder:
 
         if len(matches) != 1:
             raise err.UserFacingError(
-                f"Failed to build package '{pkgname}', because the pkg file cannot be determined."
+                f"Failed to build package '{pkgname}', because the pkg file cannot be determined. Possible files are: {matches}"
             )
 
         return matches[0]
@@ -1100,6 +1111,9 @@ class PackageBuilder:
                 raise err.UserFacingError("Building aborted.")
 
         except subprocess.CalledProcessError as error:
+            if conf.suppress_command_output:
+                l.print_error("Output:")
+                l.print_continuation(error.output)
             raise err.UserFacingError(
                 f"Failed to clone and review PKGBUILD from {git_url}"
             ) from error