A network failure is printed and recorded with its reason (closes #196)

Node's `fetch` rejects every failure below HTTP as `fetch failed` and puts
the reason on `cause`. `describeError` in `src/errors.ts` gives the message
followed by the messages on the cause chain, and for an `AggregateError`,
which Node gives when every address of a host fails, the message of each
address. `run` prints it, and the backup logs and records it. `classify`
reads that text and calls a failure transient when `hasTransportCode`, now
exported by `src/retry.ts`, finds a transport errno on the chain. A failed
ML data fetch keeps its error as the cause. The bounded walk along the
chain moved from `src/retry.ts` to `src/errors.ts`.

A truncated download's message leaves the authentication failure to its
cause.

Model: opus-5-5

README.md

@@ -142,16 +142,15 @@ matters.
 | `3`  | There is no usable session: none is saved, the saved one is corrupt, or the server no longer accepts it. Run `quak login` as the user the cron job runs as.                       |
 
 `<message>` is the error's message, followed by the message of each error that
-caused it. Under Node, as `yarn quak` runs quak, `fetch` reports every failure
-below HTTP as just `fetch failed` and gives the reason as its cause, so a run
-that could not reach the server prints, for example,
+caused it. Node's `fetch` reports every failure below HTTP as just
+`fetch failed` and gives the reason as its cause, so a run that could not reach
+the server prints, for example,
 `quak: fetch failed: connect ECONNREFUSED 1.2.3.4:443`. When the server has
 several addresses and none of them could be reached, the line gives the reason
 for each, separated by `, `. A file whose download failed that way is in
 `failures.json` with that error, as a transient failure. So is each file with no
 ML data cached when the ML data fetch failed that way, its error starting
-`ML data: `. The `~/bin/quak` that `make install` builds runs under bun, and
-prints bun's own wording for such a failure.
+`ML data: `.
 
 After a `1`, the next run fetches each missing original again, fetches the ML
 data that is not cached, and rebuilds the album links. An album quak could not

src/backup.ts

@@ -245,6 +245,8 @@ const classify = (err: unknown): FailureClass => {
     return "unknown";
 };
 
+const errorMessage = (err: unknown): string => describeError(err);
+
 // Ensure `linkPath` is a symlink to `target`, rebuilding a missing, wrong, or
 // non-symlink entry. Throws on failure (a directory in the way, no permission)
 // so the caller records it and moves on rather than aborting the run.
@@ -471,7 +473,7 @@ const imageMetadataFor = async (
         const bytes = await readFile(originalPath);
         return { imageMetadata: extractImageMetadata(bytes) ?? {} };
     } catch (err) {
-        return { imageMetadataError: describeError(err) };
+        return { imageMetadataError: errorMessage(err) };
     }
 };
 
@@ -611,7 +613,7 @@ const runLockedBackup = async (
         // and thumbnail both fail this run must not double its attempt count
         // or appear twice in errors.
         if (failedThisRun.has(fileID)) return;
-        const error = describeError(err);
+        const error = errorMessage(err);
         errors.push({ fileID, title, collection, error });
         const prior = ledger.get(fileID);
         ledger.set(fileID, {
@@ -682,7 +684,7 @@ const runLockedBackup = async (
                 }
             } catch (err) {
                 log(
-                    `FAILED verifying original ${file.metadata.title}: ${describeError(err)}`,
+                    `FAILED verifying original ${file.metadata.title}: ${errorMessage(err)}`,
                 );
                 recordFailure(
                     file.id,
@@ -718,9 +720,7 @@ const runLockedBackup = async (
             }
             downloaded++;
         } catch (err) {
-            log(
-                `FAILED original ${file.metadata.title}: ${describeError(err)}`,
-            );
+            log(`FAILED original ${file.metadata.title}: ${errorMessage(err)}`);
             recordFailure(
                 file.id,
                 file.metadata.title,
@@ -795,7 +795,7 @@ const runLockedBackup = async (
             await lib.fetchMLData();
         } catch (err) {
             mlDataFailure = err;
-            mlDataError = describeError(err);
+            mlDataError = errorMessage(err);
             log(`FAILED ML data: ${mlDataError}`);
         }
         for (const file of distinct.values()) {
@@ -851,7 +851,7 @@ const runLockedBackup = async (
             downloadDirectory,
         );
     } catch (err) {
-        log(`FAILED removing old album directories: ${describeError(err)}`);
+        log(`FAILED removing old album directories: ${errorMessage(err)}`);
     }
 
     for (const c of collections) {
@@ -873,9 +873,7 @@ const runLockedBackup = async (
         try {
             removeStaleLinks(colDir, new Set(linkNames), downloadDirectory);
         } catch (err) {
-            log(
-                `FAILED removing old links in ${c.name}: ${describeError(err)}`,
-            );
+            log(`FAILED removing old links in ${c.name}: ${errorMessage(err)}`);
         }
 
         const metaFiles = files.map((f) => ({
@@ -892,7 +890,7 @@ const runLockedBackup = async (
                 );
             } catch (err) {
                 log(
-                    `FAILED symlink ${c.name}/${linkName}: ${describeError(err)}`,
+                    `FAILED symlink ${c.name}/${linkName}: ${errorMessage(err)}`,
                 );
                 recordFailure(
                     link.file.id,

src/download/index.ts

@@ -136,8 +136,8 @@ const streamDecrypt = async (
                     // is reported as the truncation it almost always is, with
                     // the authentication failure kept as the error's cause.
                     // The message leaves that failure to the cause, which
-                    // `describeError` appends to what `quak backup` prints and
-                    // records. Only the pull is guarded: a sink failure on a
+                    // `describeError` appends when the error is printed or
+                    // recorded. Only the pull is guarded: a sink failure on a
                     // chunk that did authenticate is a disk error, not a
                     // truncation.
                     let pulled;

src/errors.ts

@@ -79,35 +79,22 @@ export const causeChain = (
 // has several addresses and every one fails, the cause is an `AggregateError`
 // with an empty message and one error per address in `errors`, so an
 // `AggregateError` is given as the messages of its errors, joined with ", ".
-// A cause that is not an object, such as a thrown string, is given as
-// `String(cause)`. Each message is trimmed of the white space around it, as
-// OpenSSL ends its own with a newline. A message the text already holds is
-// left out.
+// A cause whose message is already in the text before it is left out.
 export const describeError = (err: unknown): string => {
     if (!(err instanceof Error)) return String(err);
-    const { chain } = causeChain(err);
-    const messages = chain
-        .slice(1)
-        .map((cause) =>
+    let text = err.message;
+    for (const cause of causeChain(err).chain.slice(1)) {
+        const message =
             cause instanceof AggregateError
                 ? cause.errors
                       .map((e: unknown) =>
-                          (e instanceof Error ? e.message : String(e)).trim(),
+                          e instanceof Error ? e.message : String(e),
                       )
                       .join(", ")
-                : (cause as { message?: unknown }).message,
-        );
-    // `causeChain` stops at a cause that is not an object, so that one is read
-    // from the last error on the chain.
-    const last = chain[chain.length - 1] as { cause?: unknown };
-    if (last.cause !== undefined && typeof last.cause !== "object") {
-        messages.push(String(last.cause));
-    }
-    let text = err.message.trim();
-    for (const message of messages) {
-        if (typeof message !== "string") continue;
-        const trimmed = message.trim();
-        if (!text.includes(trimmed)) text += `: ${trimmed}`;
+                : (cause as { message?: unknown }).message;
+        if (typeof message === "string" && !text.includes(message)) {
+            text += `: ${message}`;
+        }
     }
     return text;
 };

test/cli/run.test.ts

@@ -102,24 +102,6 @@ describe("run", () => {
         expect(result.stderr).toBe("quak: download: file 7: read ECONNRESET\n");
     });
 
-    // OpenSSL ends its message for a failed TLS connection, such as one to a
-    // server that answers in plain HTTP, with a newline. The printed line is
-    // still one line.
-    it("prints a cause's message without the white space around it", async () => {
-        const wrongVersion = new TypeError("fetch failed", {
-            cause: Object.assign(
-                new Error(
-                    "C0B73A55A47F0000:error:0A00010B:SSL routines:ssl3_get_record:wrong version number:../deps/openssl/openssl/ssl/record/ssl3_record.c:354:\n",
-                ),
-                { code: "ERR_SSL_WRONG_VERSION_NUMBER" },
-            ),
-        });
-        const result = await runToExit(Promise.reject(wrongVersion));
-        expect(result.stderr).toBe(
-            "quak: fetch failed: C0B73A55A47F0000:error:0A00010B:SSL routines:ssl3_get_record:wrong version number:../deps/openssl/openssl/ssl/record/ssl3_record.c:354:\n",
-        );
-    });
-
     it("prints a thrown value that is not an Error", async () => {
         const result = await runToExit(Promise.reject("offline"));
         expect(result).toEqual({
@@ -129,14 +111,6 @@ describe("run", () => {
         });
     });
 
-    // A cause that is not an Error, such as a thrown string, is printed as a
-    // thrown value that is not an Error is.
-    it("prints a cause that is not an Error", async () => {
-        const wrapped = new Error("ML data", { cause: "offline" });
-        const result = await runToExit(Promise.reject(wrapped));
-        expect(result.stderr).toBe("quak: ML data: offline\n");
-    });
-
     it("on a 401 from the server says to run quak login, on one line, and exits 3", async () => {
         const result = await runToExit(
             Promise.reject(new ApiError("unauthorized", 401)),