app.py: str(e) instead of "{}".format(e)aevri/str_e

We're not implementing __format__ anywhere, so there's no reason to
prefer format() over the more conventional conversion with str().

In one case no conversion is needed at all, so remove it.

In another case the conversion is better done in the called function
(_notify), not where the function is called.

For the _message case, there are quite a few places that might need
fixing up, so that is left for later work.

Note that SubprocessError is a vanilla subclass of Exception:
https://github.com/python/cpython/blob/bafa8487f77fa076de3a06755399daf81cb75598/Lib/subprocess.py#L96

4 files changed, 7 insertions, 7 deletions

diff --git a/buildstream/_frontend/app.py b/buildstream/_frontend/app.py
index c1a5e57b7..67fcc8370 100644
--- a/buildstream/_frontend/app.py
+++ b/buildstream/_frontend/app.py
@@ -272,7 +272,7 @@ class App():
                     self._message(MessageType.FAIL, session_name, elapsed=elapsed)
 
                     # Notify session failure
-                    self._notify("{} failed".format(session_name), "{}".format(e))
+                    self._notify("{} failed".format(session_name), e)
 
                 if self._started:
                     self._print_summary()
@@ -431,7 +431,7 @@ class App():
     #
     def _notify(self, title, text):
         if self.interactive:
-            self.notify(title, text)
+            self.notify(str(title), str(text))
 
     # Local message propagator
     #
@@ -658,7 +658,7 @@ class App():
     #
     def _error_exit(self, error, prefix=None):
         click.echo("", err=True)
-        main_error = "{}".format(error)
+        main_error = str(error)
         if prefix is not None:
             main_error = "{}: {}".format(prefix, main_error)
 
@@ -666,7 +666,7 @@ class App():
         if error.detail:
             indent = " " * INDENT
             detail = '\n' + indent + indent.join(error.detail.splitlines(True))
-            click.echo("{}".format(detail), err=True)
+            click.echo(detail, err=True)
 
         sys.exit(-1)
 
diff --git a/buildstream/_frontend/widget.py b/buildstream/_frontend/widget.py
index 15bd9cf79..45be6d136 100644
--- a/buildstream/_frontend/widget.py
+++ b/buildstream/_frontend/widget.py
@@ -486,7 +486,7 @@ class LogLine(Widget):
         values["Session Start"] = starttime.strftime('%A, %d-%m-%Y at %H:%M:%S')
         values["Project"] = "{} ({})".format(project.name, project.directory)
         values["Targets"] = ", ".join([t.name for t in stream.targets])
-        values["Cache Usage"] = "{}".format(context.get_cache_usage())
+        values["Cache Usage"] = str(context.get_cache_usage())
         text += self._format_values(values)
 
         # User configurations
diff --git a/buildstream/_stream.py b/buildstream/_stream.py
index 4a21f5002..3276b4081 100644
--- a/buildstream/_stream.py
+++ b/buildstream/_stream.py
@@ -553,7 +553,7 @@ class Stream():
             try:
                 self._artifacts.remove(ref, defer_prune=True)
             except CASCacheError as e:
-                self._message(MessageType.WARN, "{}".format(e))
+                self._message(MessageType.WARN, str(e))
                 continue
 
             self._message(MessageType.INFO, "Removed: {}".format(ref))
diff --git a/buildstream/sandbox/_sandboxchroot.py b/buildstream/sandbox/_sandboxchroot.py
index 71422476a..7266a00e3 100644
--- a/buildstream/sandbox/_sandboxchroot.py
+++ b/buildstream/sandbox/_sandboxchroot.py
@@ -188,7 +188,7 @@ class SandboxChroot(Sandbox):
             # Exceptions in preexec_fn are simply reported as
             # 'Exception occurred in preexec_fn', turn these into
             # a more readable message.
-            if '{}'.format(e) == 'Exception occurred in preexec_fn.':
+            if str(e) == 'Exception occurred in preexec_fn.':
                 raise SandboxError('Could not chroot into {} or chdir into {}. '
                                    'Ensure you are root and that the relevant directory exists.'
                                    .format(rootfs, cwd)) from e